1
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Bang RS, Verster L, Hong H, Pal L, Velev OD. Colloidal Engineering of Microplastic Capture with Biodegradable Soft Dendritic "Microcleaners". Langmuir 2024; 40:5923-5933. [PMID: 38428025 DOI: 10.1021/acs.langmuir.3c03869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2024]
Abstract
The introduction of colloidal principles that enable efficient microplastic collection from aquatic environments is a goal of great environmental importance. Here, we present a novel method of microplastic (MP) collection using biodegradable hydrogel soft dendritic colloids (hSDCs). These dendritic colloids have abundant nanofibrils and a large surface area, which provide an abundance of interfacial interactions and excellent networking capabilities, allowing for the capture of plastic particles and other contaminants. Here, we show how the polymer composition and morphology of the hSDCs can impact the capture of microplastics modeled by latex microbeads. Additionally, we use colloidal DLVO theory to interpret the capture efficiencies of microbeads of different sizes and surface functional groups. The results demonstrate the microplastic remediation efficiency of hydrogel dendricolloids and highlight the primary factors involved in the microbead interactions and adsorption. On a practical level, the results show that the development of environmentally benign microcleaners based on naturally sourced materials could present a sustainable solution for microplastic cleanup.
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Affiliation(s)
- Rachel S Bang
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Lucille Verster
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
- Department of Forest Biomaterials, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Haeleen Hong
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Lokendra Pal
- Department of Forest Biomaterials, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
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2
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Saha T, Mukherjee S, Dickey MD, Velev OD. Harvesting and manipulating sweat and interstitial fluid in microfluidic devices. Lab Chip 2024; 24:1244-1265. [PMID: 38197332 DOI: 10.1039/d3lc00874f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Microfluidic devices began to be used to facilitate sweat and interstitial fluid (ISF) sensing in the mid-2010s. Since then, numerous prototypes involving microfluidics have been developed in different form factors for sensing biomarkers found in these fluids under in vitro, ex vivo, and in vivo (on-body) settings. These devices transport and manipulate biofluids using microfluidic channels composed of silicone, polymer, paper, or fiber. Fluid flow transport and sample management can be achieved by controlling the flow rate, surface morphology of the channel, and rate of fluid evaporation. Although many devices have been developed for estimating sweat rate, electrolyte, and metabolite levels, only a handful have been able to proceed beyond laboratory testing and reach the stage of clinical trials and commercialization. To further this technology, this review reports on the utilization of microfluidics towards sweat and ISF management and transport. The review is distinguished from other recent reviews by focusing on microfluidic principles of sweat and ISF generation, transport, extraction, and management. Challenges and prospects are highlighted, with a discussion on how to transition such prototypes towards personalized healthcare monitoring systems.
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Affiliation(s)
- Tamoghna Saha
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Sneha Mukherjee
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Michael D Dickey
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
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3
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Agate S, Williams A, Dougherty J, Velev OD, Pal L. Polymer Color Intelligence: Effect of Materials, Instruments, and Measurement Techniques - A Review. ACS Omega 2023; 8:23257-23270. [PMID: 37426280 PMCID: PMC10324080 DOI: 10.1021/acsomega.2c08252] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 05/24/2023] [Indexed: 07/11/2023]
Abstract
Transparent polymers and plastics are used to create molded parts and films for many applications. The colors of these products are of great importance for the suppliers, manufacturers, and end-users. However, for simplicity of the processing, the plastics are produced in the form of small pellets or granules. The predictive measurement of the color of such materials is a challenging process and needs consideration of a complex set of factors. A combination of color measurement systems in transmittance and reflectance modes need to be used for such materials, along with the techniques for minimizing the artifacts based on surface texture and particle sizes. This article provides an extensive overview and discussion of the various factors that can affect the perceptive colors and the methods used for the characterization of the colors and minimizing the measuring artifacts.
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Affiliation(s)
- Sachin Agate
- Department
of Forest Biomaterials, North Carolina State
University, Raleigh, North Carolina 27695, United States
| | - Austin Williams
- Department
of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Joseph Dougherty
- Eastman
Chemical Company, 200 S Wilcox Dr, Kingsport, Tennessee 37660, United States
| | - Orlin D. Velev
- Department
of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Lokendra Pal
- Department
of Forest Biomaterials, North Carolina State
University, Raleigh, North Carolina 27695, United States
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4
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Dorsey MA, Velev OD, Hall CK. Computational investigation of the phase behavior of colloidal squares with offset magnetic dipoles. Soft Matter 2023. [PMID: 37249009 DOI: 10.1039/d3sm00081h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Colloidal particles with anisotropic shapes and interactions display rich phase behavior and have potential as structural bases for materials with controllable properties. In this paper, we explore the self-assembling characteristics of a new class of particles that have been shown experimentally to form reconfigurable structures: microscopic cube-shaped colloids with a magnetic dipole that is transversely offset from the particle's center of mass. We have performed in silico simulations of the dynamics of large numbers of dipolar squares in two-dimensions using discontinuous molecular dynamics (DMD). We use a coarse-grain method where the dipolar microcubes are represented by a group of four hard circles bonded together to create a rigid square in two-dimensions and two opposite charges are embedded within the square to represent a magnetic dipole. Annealing, or "slow-cooling", simulations are conducted to determine the equilibrium structures. Systems of dipolar squares tend to assemble into one of two different types of conformations: either single- or double-stranded assemblies, each with unique structures and phase diagrams in the temperature-density plane. Single-stranded assemblies form highly interconnected percolated, or gel-like, networks. In contrast, double stranded assemblies tend to form globally-aligned nematic states at high densities, although this is not seen consistently in all runs. The phase behavior of systems of dipolar squares depends not only on the system's temperature and density, but also on the type of dipole embedded within the square and on the relative number of squares with an opposite "handedness" that are present within the system.
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Affiliation(s)
- Matthew A Dorsey
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27606, USA.
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27606, USA.
| | - Carol K Hall
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27606, USA.
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5
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Basu A, Okello LB, Castellanos N, Roh S, Velev OD. Assembly and manipulation of responsive and flexible colloidal structures by magnetic and capillary interactions. Soft Matter 2023; 19:2466-2485. [PMID: 36946137 DOI: 10.1039/d3sm00090g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The long-ranged interactions induced by magnetic fields and capillary forces in multiphasic fluid-particle systems facilitate the assembly of a rich variety of colloidal structures and materials. We review here the diverse structures assembled from isotropic and anisotropic particles by independently or jointly using magnetic and capillary interactions. The use of magnetic fields is one of the most efficient means of assembling and manipulating paramagnetic particles. By tuning the field strength and configuration or by changing the particle characteristics, the magnetic interactions, dynamics, and responsiveness of the assemblies can be precisely controlled. Concurrently, the capillary forces originating at the fluid-fluid interfaces can serve as means of reconfigurable binding in soft matter systems, such as Pickering emulsions, novel responsive capillary gels, and composites for 3D printing. We further discuss how magnetic forces can be used as an auxiliary parameter along with the capillary forces to assemble particles at fluid interfaces or in the bulk. Finally, we present examples how these interactions can be used jointly in magnetically responsive foams, gels, and pastes for 3D printing. The multiphasic particle gels for 3D printing open new opportunities for making of magnetically reconfigurable and "active" structures.
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Affiliation(s)
- Abhirup Basu
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Lilian B Okello
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Natasha Castellanos
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Sangchul Roh
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
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6
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Bang RS, Roh S, Williams AH, Stoyanov SD, Velev OD. Fluid Flow Templating of Polymeric Soft Matter with Diverse Morphologies. Adv Mater 2023; 35:e2211438. [PMID: 36840467 DOI: 10.1002/adma.202211438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 02/16/2023] [Indexed: 06/18/2023]
Abstract
It is challenging to find a conventional nanofabrication technique that can consistently produce soft polymeric matter of high surface area and nanoscale morphology in a way that is scalable, versatile, and easily tunable. Here, the capabilities of a universal method for fabricating diverse nano- and micro-scale morphologies based on polymer precipitation templated by the fluid streamlines in multiphasic flow are explored. It is shown that while the procedure is operationally simple, various combinations of its intertwined mechanisms can controllably and reproducibly lead to the formation of an extraordinary wide range of colloidal morphologies. By systematically investigating the process conditions, 12 distinct classes of polymer micro- and nano-structures including particles, rods, ribbons, nanosheets, and soft dendritic colloids (dendricolloids) are identified. The outcomes are interpreted by delineating the physical processes into three stages: hydrodynamic shear, capillary and mechanical breakup, and polymer precipitation rate. The insights into the underlying fundamental mechanisms provide guidance toward developing a versatile and scalable nanofabrication platform. It is verified that the liquid shear-based technique is versatile and works well with many chemically diverse polymers and biopolymers, showing potential as a universal tool for simple and scalable nanofabrication of many morphologically distinct soft matter classes.
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Affiliation(s)
- Rachel S Bang
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Sangchul Roh
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Austin H Williams
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Simeon D Stoyanov
- Food, Chemical, and Biotechnology cluster, Singapore Institute of Technology, 10 Dover Drive, Singapore, Singapore, 138683, Singapore
- Physical Chemistry and Soft Matter, Wageningen University and Research, Stippeneng 4, Wageningen, 6708 WE, Netherlands
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
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7
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Bang RS, Bergman M, Li T, Mukherjee F, Alshehri AS, Abbott NL, Crook NC, Velev OD, Hall CK, You F. An integrated chemical engineering approach to understanding microplastics. AIChE J 2023. [DOI: 10.1002/aic.18020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Rachel S. Bang
- Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh NC USA
| | - Michael Bergman
- Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh NC USA
| | - Tianyu Li
- Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh NC USA
| | - Fiona Mukherjee
- Robert F. Smith School of Chemical and Biomolecular Engineering Cornell University Ithaca NY USA
- Department of Chemistry and Chemical Biology Cornell University Ithaca NY USA
| | - Abdulelah S. Alshehri
- Robert F. Smith School of Chemical and Biomolecular Engineering Cornell University Ithaca NY USA
- Department of Chemical Engineering, College of Engineering King Saud University Riyadh Saudi Arabia
| | - Nicholas L. Abbott
- Robert F. Smith School of Chemical and Biomolecular Engineering Cornell University Ithaca NY USA
- Department of Chemistry and Chemical Biology Cornell University Ithaca NY USA
| | - Nathan C. Crook
- Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh NC USA
| | - Orlin D. Velev
- Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh NC USA
| | - Carol K. Hall
- Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh NC USA
| | - Fengqi You
- Robert F. Smith School of Chemical and Biomolecular Engineering Cornell University Ithaca NY USA
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8
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Williams AH, Roh S, Kotb Y, Velev OD. Superhydrophobic and Anti‐Icing Coatings Made of Hierarchically Nanofibrillated Polymer Colloids. Macromol Rapid Commun 2022. [DOI: 10.1002/marc.202270067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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9
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Williams AH, Roh S, Kotb Y, Velev OD. Superhydrophobic and Anti‐Icing Coatings Made of Hierarchically Nanofibrillated Polymer Colloids. Macromol Rapid Commun 2022; 43:e2200513. [DOI: 10.1002/marc.202200513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/05/2022] [Indexed: 11/10/2022]
Affiliation(s)
- Austin H. Williams
- Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh NC 27695 USA
| | - Sangchul Roh
- Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh NC 27695 USA
| | - Yosra Kotb
- Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh NC 27695 USA
| | - Orlin D. Velev
- Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh NC 27695 USA
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10
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Conner CG, McAndrew J, Menegatti S, Velev OD. An accelerated antibody aggregation test based on time sequenced dynamic light scattering. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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11
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Saha T, Songkakul T, Knisely CT, Yokus MA, Daniele MA, Dickey MD, Bozkurt A, Velev OD. Wireless Wearable Electrochemical Sensing Platform with Zero-Power Osmotic Sweat Extraction for Continuous Lactate Monitoring. ACS Sens 2022; 7:2037-2048. [PMID: 35820167 DOI: 10.1021/acssensors.2c00830] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Wearable and wireless monitoring of biomarkers such as lactate in sweat can provide a deeper understanding of a subject's metabolic stressors, cardiovascular health, and physiological response to exercise. However, the state-of-the-art wearable and wireless electrochemical systems rely on active sweat released either via high-exertion exercise, electrical stimulation (such as iontophoresis requiring electrical power), or chemical stimulation (such as by delivering pilocarpine or carbachol inside skin), to extract sweat under low-perspiring conditions such as at rest. Here, we present a continuous sweat lactate monitoring platform combining a hydrogel for osmotic sweat extraction, with a paper microfluidic channel for facilitating sweat transport and management, a screen-printed electrochemical lactate sensor, and a custom-built wireless wearable potentiostat system. Osmosis enables zero-electrical power sweat extraction at rest, while continuous evaporation at the end of a paper channel allows long-term sensing from fresh sweat. The positioning of the lactate sensors provides near-instantaneous sensing at low sweat volume, and the custom-designed potentiostat supports continuous monitoring with ultra-low power consumption. For a proof of concept, the prototype system was evaluated for continuous measurement of sweat lactate across a range of physiological activities with changing lactate concentrations and sweat rates: for 2 h at the resting state, 1 h during medium-intensity exercise, and 30 min during high-intensity exercise. Overall, this wearable system holds the potential of providing comprehensive and long-term continuous analysis of sweat lactate trends in the human body during rest and under exercising conditions.
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Affiliation(s)
- Tamoghna Saha
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Tanner Songkakul
- Department of Electrical & Computer Engineering, North Carolina State University, 890 Oval Drive, Raleigh, North Carolina 27695, United States
| | - Charles T Knisely
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Murat A Yokus
- Department of Electrical & Computer Engineering, North Carolina State University, 890 Oval Drive, Raleigh, North Carolina 27695, United States
| | - Michael A Daniele
- Department of Electrical & Computer Engineering, North Carolina State University, 890 Oval Drive, Raleigh, North Carolina 27695, United States.,Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina at Chapel Hill, 911 Oval Drive, Raleigh, North Carolina 27695, United States
| | - Michael D Dickey
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Alper Bozkurt
- Department of Electrical & Computer Engineering, North Carolina State University, 890 Oval Drive, Raleigh, North Carolina 27695, United States
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
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12
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Williams SJ, Islam S, Velev OD. Light scattering of colloidal suspensions: formation and stability in bourbon whiskeys. J Institute Brewing 2022. [DOI: 10.1002/jib.689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Stuart J. Williams
- Department of Mechanical Engineering University of Louisville Louisville KY USA
| | - Sabina Islam
- Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh NC USA
| | - Orlin D. Velev
- Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh NC USA
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13
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Abstract
![]()
The antinoroviral
effect of copper ions is well known, yet most
of this work has previously been conducted in copper and copper alloy
surfaces, not copper ions in solution. In this work, we characterized
the effects that Cu ions have on human norovirus capsids’ and
surrogates’ integrity to explain empirical data, indicating
virus inactivation by copper alloy surfaces, and as means of developing
novel metal ion-based virucides. Comparatively high concentrations
of Cu(II) ions (>10 mM) had little effect on the infectivity of
human
norovirus surrogates, so we used sodium ascorbate as a reducing agent
to generate unstable Cu(I) ions from solutions of copper bromide.
We found that significantly lower concentrations of monovalent copper
ions (∼0.1 mM) compared to divalent copper ions cause capsid
protein damage that prevents human norovirus capsids from binding
to cell receptors in vitro and induce a greater than
4-log reduction in infectivity of Tulane virus, a human norovirus
surrogate. Further, these Cu(I) solutions caused reduction of GII.4
norovirus from stool in suspension, producing about a 2-log reduction
of virus as measured by a reverse transcriptase-quantitative polymerase
chain reaction. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis
(SDS-PAGE) data indicate substantial major capsid protein cleavage
of both GI.7 and GII.4 norovirus capsids, and TEM images show the
complete loss of capsid integrity of GI.7 norovirus. GII.4 virus-like
particles (VLPs) were less susceptible to inactivation by copper ion
treatments than GI.7 VLPs based upon receptor binding and SDS-PAGE
analysis of viral capsids. The combined data demonstrate that stabilized
Cu(I) ion solutions show promise as highly effective noroviral disinfectants
in solution that can potentially be utilized at low concentrations
for inactivation of human noroviruses.
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Affiliation(s)
- Brittany S. Mertens
- Department of Chemical and Biomolecular Engineering, NC State University, Raleigh, North Carolina 27606, United States
| | - Matthew D. Moore
- Department of Food, Bioprocessing, and Nutrition Sciences, NC State University, Raleigh, North Carolina 27606, United States
- Department of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Lee-Ann Jaykus
- Department of Food, Bioprocessing, and Nutrition Sciences, NC State University, Raleigh, North Carolina 27606, United States
| | - Orlin D. Velev
- Department of Chemical and Biomolecular Engineering, NC State University, Raleigh, North Carolina 27606, United States
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14
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Ewins EJ, Han K, Bharti B, Robinson T, Velev OD, Dimova R. Controlled adhesion, membrane pinning and vesicle transport by Janus particles. Chem Commun (Camb) 2022; 58:3055-3058. [PMID: 35166272 DOI: 10.1039/d1cc07026f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The interactions between biomembranes and particles are key to many applications, but the lack of controllable model systems to study them limits the progress in their research. Here, we describe how Janus polystyrene microparticles, half coated with iron, can be partially engulfed by artificial cells, namely giant vesicles, with the goals to control and investigate their adhesion and degree of encapsulation. The interaction between the Janus particles and these model cell membrane systems is mediated by electrostatic charge, offering a further mode of modulation in addition to the iron patches. The ferromagnetic particle coatings also enable manipulation and transport of the vesicles by magnetic fields.
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Affiliation(s)
- Eleanor J Ewins
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany.
| | - Koohee Han
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Bhuvnesh Bharti
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Tom Robinson
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany.
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Rumiana Dimova
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany.
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15
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Tyagi P, Agate S, Velev OD, Lucia L, Pal L. A Critical Review of the Performance and Soil Biodegradability Profiles of Biobased Natural and Chemically Synthesized Polymers in Industrial Applications. Environ Sci Technol 2022; 56:2071-2095. [PMID: 35077140 DOI: 10.1021/acs.est.1c04710] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
This review explores biobased polymers for industrial applications, their end fate, and most importantly, origin and key aspects enabling soil biodegradation. The physicochemical properties of biobased synthetic and natural polymers and the primary factors governing degradation are explored. Current and future biobased systems and factors allowing for equivalent comparisons of degradation and possible sources for engineering improved biodegradation are reviewed. Factors impacting ultraviolet (UV) stability of biopolymers have been described including methods to enhance photoresistance and impact on biodegradation. It discusses end-fate of biopolymers in soil and impact of residues on soil health. A limited number of studies examine side effects (e.g., microbial toxicity) from soil biodegradation of composites and biopolymers. Currently available standards for biodegradation and composting have been described with limitations and scope for improvements. Finally, design considerations and implications for sustainable polymers used, under consideration, and to be considered within the context of a rational biodegradable strategy are elaborated.
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Affiliation(s)
- Preeti Tyagi
- Department of Forest Biomaterials, North Carolina State University, 431 Dan Allen Dr., Raleigh, North Carolina 27695, United States
- Global Breakthrough Packaging Group, Mars Wrigley, Chicago, Illinois 60642, United States
| | - Sachin Agate
- Department of Forest Biomaterials, North Carolina State University, 431 Dan Allen Dr., Raleigh, North Carolina 27695, United States
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, North Carolina 27695, United States
| | - Lucian Lucia
- Department of Forest Biomaterials, North Carolina State University, 431 Dan Allen Dr., Raleigh, North Carolina 27695, United States
| | - Lokendra Pal
- Department of Forest Biomaterials, North Carolina State University, 431 Dan Allen Dr., Raleigh, North Carolina 27695, United States
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16
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Williams AH, Hebert AM, Boehm RC, Huddleston ME, Jenkins MR, Velev OD, Nelson MT. Bioscaffold Stiffness Mediates Aerosolized Nanoparticle Uptake in Lung Epithelial Cells. ACS Appl Mater Interfaces 2021; 13:50643-50656. [PMID: 34668373 DOI: 10.1021/acsami.1c09701] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In this study, highly porous, ultrasoft polymeric mats mimicking human tissues were formed from novel polyurethane soft dendritic colloids (PU SDCs). PU SDCs have a unique fibrillar morphology controlled by antisolvent precipitation. When filtered from suspension, PU SDCs form mechanically robust nonwoven mats. The stiffness of the SDC mats can be tuned for physiological relevance. The unique physiochemical characteristics of the PU SDC particles dictate the mechanical properties resulting in tunable elastic moduli ranging from 200 to 800 kPa. The human lung A549 cells cultured on both stiff and soft PU SDC membranes were found to be viable, capable of supporting the air-liquid interface (ALI) cell culture, and maintained barrier integrity. Furthermore, A549 cellular viability and uptake efficiency of aerosolized tannic acid-coated gold nanoparticles (Ta-Au) was found to depend on elastic modulus and culture conditions. Ta-Au nanoparticle uptake was twofold and fourfold greater on soft PU SDCs, when cultured at submerged and ALI conditions, respectively. The significant increase in endocytosed Ta-Au resulted in a 20% decrease in viability, and a 4-fold increase in IL-8 cytokine secretion when cultured on soft PU SDCs at ALI. Common tissue culture materials exhibit super-physiological elastic moduli, a factor found to be critical in analyzing nanomaterial cellular interactions and biological responses.
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Affiliation(s)
- Austin H Williams
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Adrien M Hebert
- Air Force Research Laboratory, 711th Human Performance Wing, Wright-Patterson AFB, Ohio 45433, United States
| | - Robert C Boehm
- Air Force Research Laboratory, 711th Human Performance Wing, Wright-Patterson AFB, Ohio 45433, United States
| | - Mary E Huddleston
- Air Force Research Laboratory, 711th Human Performance Wing, Wright-Patterson AFB, Ohio 45433, United States
- UES, Inc., Dayton, Ohio 45432, United States
| | - Meghan R Jenkins
- Air Force Research Laboratory, 711th Human Performance Wing, Wright-Patterson AFB, Ohio 45433, United States
- UES, Inc., Dayton, Ohio 45432, United States
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - M Tyler Nelson
- Air Force Research Laboratory, 711th Human Performance Wing, Wright-Patterson AFB, Ohio 45433, United States
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17
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Saha T, Fang J, Yokus MA, Mukherjee S, Bozkurt A, Daniele MA, Dickey MD, Velev OD. A Wearable Patch for Prolonged Sweat Lactate Harvesting and Sensing. Annu Int Conf IEEE Eng Med Biol Soc 2021; 2021:6863-6866. [PMID: 34892683 DOI: 10.1109/embc46164.2021.9630881] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Operating at low sweat rates, such as those experienced by humans at rest, is still an unmet need for state-of-the-art wearable sweat harvesting and testing devices for lactate. Here, we report the on-skin performance of a non-invasive wearable sweat sampling patch that can harvest sweat at rest, during exercise, and post-exercise. The patch simultaneously uses osmosis and evaporation for long-term (several hours) sampling of sweat. Osmotic sweat withdrawal is achieved by skin-interfacing a hydrogel containing a concentrated solute. The gel interfaces with a paper strip that transports the fluid via wicking and evaporation. Proof of concept results show that the patch was able to sample sweat during resting and post-exercise conditions, where the lactate concentration was successfully quantified. The patch detected the increase in sweat lactate levels during medium level exercise. Blood lactate remained invariant with exercise as expected. We also developed a continuous sensing version of the patch by including enzymatic electrochemical sensors. Such a battery-free, passive, wearable sweat sampling patch can potentially provide useful information about the human metabolic activity.
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18
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Kotb Y, Cagnard A, Houston KR, Khan SA, Hsiao LC, Velev OD. What makes epoxy-phenolic coatings on metals ubiquitous: Surface energetics and molecular adhesion characteristics. J Colloid Interface Sci 2021; 608:634-643. [PMID: 34628322 DOI: 10.1016/j.jcis.2021.09.091] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/16/2021] [Accepted: 09/17/2021] [Indexed: 11/29/2022]
Abstract
HYPOTHESIS Wetting characteristics of epoxy and phenolic resins on metals depend on the molecular interactions between resins' functional groups and metal surface. Those interactions affect the practical adhesion strength of epoxy-phenolic coatings on metals. Estimation of the theoretical adhesion energies can reveal this system's microscopic adhesion mechanisms. EXPERIMENTS Adhesion is estimated theoretically based on resins' wettability on metals, and experimentally through pull-off adhesion testing of cured coatings. The effect of various functional groups on adhesion is decoupled using epoxy and phenolic resins with different functionalities. To assess the impact of the metal passivation on adhesion, tinplated and tin-free steel substrates are used. Differences in their surface chemical composition and polarity are investigated using XPS. FINDINGS Theoretical adhesion results reveal a superior adhesion of epoxy compared to phenolic resins. Moreover, epoxy resins having a higher content of epoxide-to-hydroxyl groups show improved theoretical and practical adhesion. The importance of epoxides in driving resins' initial adhesion on metals is attributed to the formation of direct chemical bonds with active hydrogen on metal surfaces. The adhesion of coatings on tin-free steel is found to be higher than on tinplated steel. This is associated to the increased hydroxyl fraction on tin-free steel surface leading to more hydrogen bonds formation.
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Affiliation(s)
- Yosra Kotb
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | | | | | - Saad A Khan
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Lilian C Hsiao
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
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19
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Castellanos NI, Bharti B, Velev OD. Field-Driven Reversible Alignment and Gelation of Magneto-Responsive Soft Anisotropic Microbeads. J Phys Chem B 2021; 125:7900-7910. [PMID: 34253016 DOI: 10.1021/acs.jpcb.1c03158] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Magnetic fields offer untethered control over the assembly, dynamics, and reconfiguration of colloidal particles. However, synthesizing "soft" colloidal particles with switchable magnetic dipole moment remains a challenge, primarily due to strong coupling of the dipoles of the adjacent nanoparticles. In this article, we present a way to overcome this fundamental challenge based on a strategy to synthesize soft microbeads with tunable residual dipole moment. The microbeads are composed of a polydimethylsiloxane (PDMS) matrix with internally embedded magnetic nanoparticles (MNPs). The distribution and orientation of the MNPs within the PDMS bead matrix is controlled by an external magnetic field during the synthesis process, thus allowing for the preparation of anisotropic PDMS microbeads with internal magnetically aligned nanoparticle chains. We study and present the differences in magnetic interactions between microbeads containing magnetically aligned MNPs and microbeads with randomly distributed MNPs. The interparticle interactions in a suspension of microbeads with embedded aligned MNP chains result in the spontaneous formation of percolated networks due to residual magnetization. We proved the tunability of the structure by applying magnetization, demagnetization, and remagnetization cycles that evoke formation, breakup, and reformation of 2D percolated networks. The mechanical response of the microbead suspension was quantified by oscillatory rheology and correlated to the propensity for network formation by the magnetic microbeads. We also experimentally correlated the 2D alignment of the microbeads to the direction of earth's magnetic field. Overall, the results prove that the soft magnetic microbeads enable a rich variety of structures and can serve as an experimental toolbox for modeling interactions in dipolar systems leading to various percolated networks, novel magneto-rheological materials, and smart gels.
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Affiliation(s)
- Natasha I Castellanos
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Bhuvnesh Bharti
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
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20
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Saha T, Fang J, Mukherjee S, Dickey MD, Velev OD. Wearable Osmotic-Capillary Patch for Prolonged Sweat Harvesting and Sensing. ACS Appl Mater Interfaces 2021; 13:8071-8081. [PMID: 33587589 DOI: 10.1021/acsami.0c22730] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Biomarkers in sweat are a largely untapped source of health information. Most of the currently available sweat harvesting and testing devices are incapable of operating under low-sweat rates such as those experienced by humans at rest. Here we analyze the in vitro and in vivo sampling of sweat through osmosis via the use of a hydrogel interfaced with the skin, without need for active perspiration. The hydrogel also interfaces with paper-based microfluidics to transport the fluid via capillary forces toward a testing zone and then evaporation pad. We show that the hydrogel solute content and area of the evaporation pad regulate the long-term extraction of sweat and its associated biomarkers. The results indicate that the platform can sample biomarkers from a model skin system continuously for approximately 12 h. On-skin testing of the platform on both resting and exercising human subjects confirms that it can sample sweat lactate directly from the surface of skin. The results highlight that lactate in sweat increases with exercise and as a direct result of muscle activity. Implementation of such new principles for sweat fluid harvesting and management via wearable patch devices can contribute toward the advancement of next generation wearables.
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Affiliation(s)
- Tamoghna Saha
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Jennifer Fang
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Sneha Mukherjee
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Michael D Dickey
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
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21
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Stine JS, Harper BJ, Conner CG, Velev OD, Harper SL. In Vivo Toxicity Assessment of Chitosan-Coated Lignin Nanoparticles in Embryonic Zebrafish ( Danio rerio). Nanomaterials (Basel) 2021; 11:E111. [PMID: 33418857 PMCID: PMC7825063 DOI: 10.3390/nano11010111] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 12/30/2020] [Accepted: 01/01/2021] [Indexed: 02/04/2023]
Abstract
Lignin is the second most abundant biopolymer on Earth after cellulose. Since lignin breaks down in the environment naturally, lignin nanoparticles may serve as biodegradable carriers of biocidal actives with minimal environmental footprint compared to conventional antimicrobial formulations. Here, a lignin nanoparticle (LNP) coated with chitosan was engineered. Previous studies show both lignin and chitosan to exhibit antimicrobial properties. Another study showed that adding a chitosan coating can improve the adsorption of LNPs to biological samples by electrostatic adherence to oppositely charged surfaces. Our objective was to determine if these engineered particles would elicit toxicological responses, utilizing embryonic zebrafish toxicity assays. Zebrafish were exposed to nanoparticles with an intact chorionic membrane and with the chorion enzymatically removed to allow for direct contact of particles with the developing embryo. Both mortality and sublethal endpoints were analyzed. Mortality rates were significantly greater for chitosan-coated LNPs (Ch-LNPs) compared to plain LNPs and control groups. Significant sublethal endpoints were observed in groups exposed to Ch-LNPs with chorionic membranes intact. Our study indicated that engineered Ch-LNP formulations at high concentrations were more toxic than plain LNPs. Further study is warranted to fully understand the mechanisms of Ch-LNP toxicity.
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Affiliation(s)
- Jared S. Stine
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA;
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA;
| | - Bryan J. Harper
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA;
| | - Cathryn G. Conner
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA; (C.G.C.); (O.D.V.)
| | - Orlin D. Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA; (C.G.C.); (O.D.V.)
| | - Stacey L. Harper
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA;
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA;
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22
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Han K, Shields CW, Bharti B, Arratia PE, Velev OD. Active Reversible Swimming of Magnetically Assembled "Microscallops" in Non-Newtonian Fluids. Langmuir 2020; 36:7148-7154. [PMID: 32011137 DOI: 10.1021/acs.langmuir.9b03698] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Miniaturized devices capable of active swimming at low Reynolds numbers are of fundamental importance and possess potential biomedical utility. The design of colloidal microswimmers requires not only miniaturizing reconfigurable structures but also understanding their interactions with media at low Reynolds numbers. We investigate the dynamics of "microscallops" made of asymmetric magnetic cubes, which are assembled and actuated using magnetic fields. One approach to achieving directional propulsion is to break the symmetry of the viscous forces by coupling the reciprocal motions of such microswimmers with the nonlinear rheology inherent in non-Newtonian fluids. When placed in shear-thinning fluids, the local viscosity gradient resulting from nonuniform shear stresses exerted by time-asymmetric strokes of the microscallops generates propulsive thrust through an effect we term "self-viscophoresis". Surprisingly, we found that the direction of propulsion changes with the size and structure of these assemblies. We analyze the origins of their directional propulsion and explain the variable propulsion direction in terms of multiple counterbalancing domains of shear dissipation around the microscale structures. The principles governing the locomotion of these microswimmers may be extended to other reconfigurable microbots assembled from colloidal-scale units.
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Affiliation(s)
- Koohee Han
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Charles Wyatt Shields
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80303, United States
| | - Bhuvnesh Bharti
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Paulo E Arratia
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
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23
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Carrithers AD, Brown MJ, Rashed MZ, Islam S, Velev OD, Williams SJ. Multiscale Self-Assembly of Distinctive Weblike Structures from Evaporated Drops of Dilute American Whiskeys. ACS Nano 2020; 14:5417-5425. [PMID: 32208622 DOI: 10.1021/acsnano.9b08984] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
When a sessile droplet of a complex mixture evaporates, its nonvolatile components may deposit into various patterns. One such phenomena, the coffee ring effect, has been a topic of interest for several decades. Here, we identify what we believe to be a fascinating phenomenon of droplet pattern deposition for another well-known beverage-what we have termed a "whiskey web". Nanoscale agglomerates were generated in diluted American whiskeys (20-25% alcohol by volume), which later stratified as microwebs on the liquid-air interface during evaporation. The web's strandlike features result from monolayer collapse, and the resulting pattern is a function of the intrinsic molecular constituents of the whiskey. Data suggest that, for our conditions (diluted 1.0 μL drops evaporated on cleaned glass substrates), whiskey webs were unique to diluted American whiskey; however, similar structures were generated with other whiskeys under different conditions. Further, each product forms their own distinct pattern, demonstrating that this phenomenon could be used for sample analysis and counterfeit identification.
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Affiliation(s)
- Adam D Carrithers
- Department of Mechanical Engineering, University of Louisville, Louisville, Kentucky 40292, United States
| | - Martin J Brown
- Department of Mechanical Engineering, University of Louisville, Louisville, Kentucky 40292, United States
| | - Mohamed Z Rashed
- Department of Mechanical Engineering, University of Louisville, Louisville, Kentucky 40292, United States
| | - Sabina Islam
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
| | - Stuart J Williams
- Department of Mechanical Engineering, University of Louisville, Louisville, Kentucky 40292, United States
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24
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Shay T, Saha T, Dickey MD, Velev OD. Principles of long-term fluids handling in paper-based wearables with capillary-evaporative transport. Biomicrofluidics 2020; 14:034112. [PMID: 32566070 PMCID: PMC7286699 DOI: 10.1063/5.0010417] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 05/11/2020] [Indexed: 05/24/2023]
Abstract
We construct and investigate paper-based microfluidic devices, which model long-term fluid harvesting, transport, sensing, and analysis in new wearables for sweat analysis. Such devices can continuously wick fluid mimicking sweat and dispose of it on evaporation pads. We characterize and analyze how the action of capillarity and evaporation can cooperatively be used to transport and process sweat mimics containing dissolved salts and model analytes. The results point out that non-invasive osmotic extraction combined with paper microfluidics and evaporative disposal can enable sweat collection and monitoring for durations longer than 10 days. We model the fluid flow in the new capillary-evaporative devices and identify the parameters enabling their long-term operation. We show that the transport rates are sufficiently large to handle natural sweat rates, while we envision that such handling can be interfaced with osmotic harvesting of sweat, a concept that we demonstrated recently. Finally, we illustrate that the salt film deposited at the evaporation pad would eventually lead to cessation of the process but at the same time will preserve a record of analytes that may be used for long-term biomarker monitoring in sweat. These principles can be implemented in future platforms for wearable skin-interfacing assays or electronic biomarker monitors.
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25
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Islam S, Velev OD. Mechanism and control of "coffee-ring erosion" phenomena in structurally colored ionomer films. Soft Matter 2020; 16:2683-2694. [PMID: 32026917 DOI: 10.1039/c9sm02457c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ionomer polyesters have polymer backbones functionalized with charged groups that make them water-dispersible. Despite the widespread use of ionomer polymers in environmentally friendly coatings without volatile organic solvents, the fundamental understanding of their film formation properties is still limited. In the study, we deposited polyester nanofilms of brilliant structural colors and correlated the macroscale optical properties to the microscale thickness of the thin films. We found that sessile water droplets deposited on these films drive the formation of a rich variety of structures by an evaporation-induced effect of "coffee-ring erosion". The ionomers spontaneously get partially re-dispersed in the form of nanoparticles in the sessile droplets and driven by convective evaporation flows, become redistributed in multiple colorful ring patterns. By using the structural colors as means to follow the polymer redistribution, we characterized further the coffee-ring patterns and found that the generated patterns are dictated by polymer composition but are mostly independent on molecular weight. As expected by colloidal theory, this phenomenon was suppressed in presence of electrolytes. Furthermore, we show that the integrity of these thin polyester films can be significantly improved by thermal densification without any further chemical curing.
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Affiliation(s)
- Sabina Islam
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
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26
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Roh S, Williams AH, Bang RS, Stoyanov SD, Velev OD. Soft dendritic microparticles with unusual adhesion and structuring properties. Nat Mater 2019; 18:1315-1320. [PMID: 31611673 DOI: 10.1038/s41563-019-0508-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 09/13/2019] [Indexed: 06/10/2023]
Abstract
The interplay between morphology, excluded volume and adhesivity of particles critically determines the physical properties of numerous soft materials and coatings1-6. Branched particles2 or nanofibres3, nanofibrillated cellulose4 or fumed silica5 can enhance the structure-building abilities of colloids, whose adhesion may also be increased by capillarity or binding agents6. Nonetheless, alternative mechanisms of strong adhesion found in nature involve fibrillar mats with numerous subcontacts (contact splitting)7-11 as seen in the feet of gecko lizards and spider webs12-17. Here, we describe the fabrication of hierarchically structured polymeric microparticles having branched nanofibre coronas with a dendritic morphology. Polymer precipitation in highly turbulent flow results in microparticles with fractal branching and nanofibrillar contact splitting that exhibit gelation at very low volume fractions, strong interparticle adhesion and binding into coatings and non-woven sheets. These soft dendritic particles also have potential advantages for food, personal care or pharmaceutical product formulations.
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Affiliation(s)
- Sangchul Roh
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA
| | - Austin H Williams
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA
| | - Rachel S Bang
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA
| | - Simeon D Stoyanov
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA
- Physical Chemistry and Soft Matter, Wageningen University, Wageningen, the Netherlands
- Department of Mechanical Engineering, University College London, London, UK
- Unilever Research and Development, Vlaardingen, the Netherlands
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA.
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27
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Ma F, Zhang A, Chang D, Velev OD, Wiltberger K, Kshirsagar R. Real-time monitoring and control of CHO cell apoptosis by in situ multifrequency scanning dielectric spectroscopy. Process Biochem 2019. [DOI: 10.1016/j.procbio.2019.02.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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28
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Rohde RC, Basu A, Okello LB, Barbee MH, Zhang Y, Velev OD, Nelson A, Craig SL. Mechanochromic composite elastomers for additive manufacturing and low strain mechanophore activation. Polym Chem 2019. [DOI: 10.1039/c9py01053j] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Composite silicone inks provide access to 3D-printable elastomers that are mechanochemically active at lower strains that single component analogs.
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Affiliation(s)
| | - Amrita Basu
- Department of Chemistry
- University of Washington
- Seattle
- USA
| | - Lilian B. Okello
- Department of Chemical and Biomolecular Engineering
- North Carolina State University
- Raleigh
- USA
| | | | - Yudi Zhang
- Department of Chemistry
- Duke University
- Durham
- USA
| | - Orlin D. Velev
- Department of Chemical and Biomolecular Engineering
- North Carolina State University
- Raleigh
- USA
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29
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Rutkevičius M, Allred S, Velev OD, Velikov KP. Stabilization of oil continuous emulsions with colloidal particles from water-insoluble plant proteins. Food Hydrocoll 2018. [DOI: 10.1016/j.foodhyd.2018.04.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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30
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Affiliation(s)
- Sangchul Roh
- Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh North Carolina
| | - Orlin D. Velev
- Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh North Carolina
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31
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Nix CE, Harper BJ, Conner CG, Richter AP, Velev OD, Harper SL. Toxicological Assessment of a Lignin Core Nanoparticle Doped with Silver as an Alternative to Conventional Silver Core Nanoparticles. Antibiotics (Basel) 2018; 7:E40. [PMID: 29734649 PMCID: PMC6023088 DOI: 10.3390/antibiotics7020040] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 04/27/2018] [Accepted: 05/02/2018] [Indexed: 01/09/2023] Open
Abstract
Elevated levels of silver in the environment are anticipated with an increase in silver nanoparticle (AgNP) production and use in consumer products. To potentially reduce the burden of silver ion release from conventional solid core AgNPs, a lignin-core particle doped with silver ions and surface-stabilized with a polycationic electrolyte layer was engineered. Our objective was to determine whether any of the formulation components elicit toxicological responses using embryonic zebrafish. Ionic silver and free surface stabilizer were the most toxic constituents, although when associated separately or together with the lignin core particles, the toxicity of the formulations decreased significantly. The overall toxicity of lignin formulations containing silver was similar to other studies on a silver mass basis, and led to a significantly higher prevalence of uninflated swim bladder and yolk sac edema. Comparative analysis of dialyzed samples which had leached their loosely bound Ag⁺, showed a significant increase in mortality immediately after dialysis, in addition to eliciting significant increases in types of sublethal responses relative to the freshly prepared non-dialyzed samples. ICP-OES/MS analysis indicated that silver ion release from the particle into solution was continuous, and the rate of release differed when the surface stabilizer was not present. Overall, our study indicates that the lignin core is an effective alternative to conventional solid core AgNPs for potentially reducing the burden of silver released into the environment from a variety of consumer products.
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Affiliation(s)
- Cassandra E Nix
- Department of Environmental & Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA.
| | - Bryan J Harper
- Department of Environmental & Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA.
| | - Cathryn G Conner
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27606, USA.
| | - Alexander P Richter
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27606, USA.
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27606, USA.
| | - Stacey L Harper
- Department of Environmental & Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA.
- Oregon Nanoscience and Microtechnologies Institute, Corvallis, OR 97330, USA.
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA.
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32
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Abstract
Soft and stretchable materials play an important role in the emerging fields of soft robotics, human-machine interfaces, and stretchable electronics. Hydrogels are compelling materials because they are soft, chemically tunable, biocompatible, and ionically conductive. Hydrogels have been used as components of skin mountable sensors, such as electrocardiogram (ECG) electrodes, and show promise in emerging devices as stretchable, transparent electrodes. Ultimately, these types of devices interface the hydrogel with rigid metallic electrodes to connect with electronic circuitry. Here, we show it is possible to interface hydrogel with liquid metal (eutectic gallium indium, EGaIn) electrodes to create completely soft and deformable electrodes that provide low resistance traces through the gel without altering its mechanical properties. As a case study, we created and tested electrodes for ECG monitoring. ECG electrodes require low impedance at biomedically relevant frequencies (1-50 Hz). Potentiostatic electrochemical impedance spectroscopy measurements show that capacitive effects at the hydrogel-EGaIn interface dominate the impedance at these low frequencies, yet can be reduced by interfacing the metal with acidic or basic hydrogels that remove the native oxide skin from the metal. Increasing the ionic strength of the hydrogel also helps in lowering the impedance of the metal-hydrogel electrodes. The resulting devices have signal-to-noise ratios that exceed commercial ECG electrodes. The softness of these hydrogels can be modified without compromising the electrical properties to create truly soft electrodes. Interfacing liquid metal conductors with hydrogels represents a potential strategy of creating soft electrodes for various bioelectronic applications, e-skins, and next-generation soft robotics.
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Affiliation(s)
- Tim Shay
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, USA.
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33
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Islam S, Inglefield DL, Velev OD. Revisiting the colloidal fundamentals of water-dispersible polyesters: interactions and self-assembly of polymer nanoaggregates in water. Soft Matter 2018; 14:2118-2130. [PMID: 29488992 DOI: 10.1039/c7sm02536j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Water-dispersible sulfopolyesters are a major class of film-forming and solution-modifying polymers, which are routinely used in applications such as inks, adhesives, coatings, and personal care products. Since these polyesters are designed to be used as waterborne dispersions, understanding their colloidal interactions in dispersions is critical for their application. By using a range of commercially available water-dispersible sulfopolyesters as a model system, we investigated the relationship between their molecular composition, colloidal interactions, and phase equilibria. We established how these polyesters undergo different molecular configurations and nanoaggregated states, depending on the nature of the liquid medium. For example, the polyesters are in a solvated molecular form in certain organic solvents, whereas they self-assemble into compact nanoaggregates in water. We found that the interactions of these nanoaggregates follow the classical DLVO theory of critical colloidal coagulation where the stability of these nanoparticles is extremely sensitive to multivalent electrolytes (i.e., Ccrit ∝ z-6). By using static, dynamic, and electrophoretic light scattering, we correlate their nanoscale intermolecular and interparticle interactions with corresponding macroscale phase behavior in both organic medium and water, based on the theoretical framework of second virial coefficients. We present a model for nanoaggregate formation in water based on the critical surface charge density of these nanoparticles. Such fundamental understanding of colloidal interactions could be used to efficiently control and improve the colloidal stability and film-formation ability of these polyesters and may enable the design of novel high-performance surfactant-free waterborne dispersion systems.
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Affiliation(s)
- Sabina Islam
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
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Han K, Shields CW, Diwakar NM, Bharti B, López GP, Velev OD. Sequence-encoded colloidal origami and microbot assemblies from patchy magnetic cubes. Sci Adv 2017; 3:e1701108. [PMID: 28798960 PMCID: PMC5544397 DOI: 10.1126/sciadv.1701108] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 06/30/2017] [Indexed: 05/19/2023]
Abstract
Colloidal-scale assemblies that reconfigure on demand may serve as the next generation of soft "microbots," artificial muscles, and other biomimetic devices. This requires the precise arrangement of particles into structures that are preprogrammed to reversibly change shape when actuated by external fields. The design and making of colloidal-scale assemblies with encoded directional particle-particle interactions remain a major challenge. We show how assemblies of metallodielectric patchy microcubes can be engineered to store energy through magnetic polarization and release it on demand by microscale reconfiguration. The dynamic pattern of folding and reconfiguration of the chain-like assemblies can be encoded in the sequence of the cube orientation. The residual polarization of the metallic facets on the microcubes leads to local interactions between the neighboring particles, which is directed by the conformational restrictions of their shape after harvesting energy from external magnetic fields. These structures can also be directionally moved, steered, and maneuvered by global forces from external magnetic fields. We illustrate these capabilities by examples of assemblies of specific sequences that can be actuated, reoriented, and spatially maneuvered to perform microscale operations such as capturing and transporting live cells, acting as prototypes of microbots, micromixers, and other active microstructures.
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Affiliation(s)
- Koohee Han
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695–7905, USA
- Research Triangle Materials Research Science and Engineering Center, Durham, NC 27708, USA
| | - C. Wyatt Shields
- Research Triangle Materials Research Science and Engineering Center, Durham, NC 27708, USA
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Nidhi M. Diwakar
- Research Triangle Materials Research Science and Engineering Center, Durham, NC 27708, USA
| | - Bhuvnesh Bharti
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695–7905, USA
- Research Triangle Materials Research Science and Engineering Center, Durham, NC 27708, USA
| | - Gabriel P. López
- Research Triangle Materials Research Science and Engineering Center, Durham, NC 27708, USA
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
- Corresponding author. (O.D.V.); (G.P.L.)
| | - Orlin D. Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695–7905, USA
- Research Triangle Materials Research Science and Engineering Center, Durham, NC 27708, USA
- Corresponding author. (O.D.V.); (G.P.L.)
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Roh S, Parekh DP, Bharti B, Stoyanov SD, Velev OD. 3D Printing by Multiphase Silicone/Water Capillary Inks. Adv Mater 2017; 29. [PMID: 28590510 DOI: 10.1002/adma.201701554] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Revised: 04/17/2017] [Indexed: 05/09/2023]
Abstract
3D printing of polymers is accomplished easily with thermoplastics as the extruded hot melt solidifies rapidly during the printing process. Printing with liquid polymer precursors is more challenging due to their longer curing times. One curable liquid polymer of specific interest is polydimethylsiloxane (PDMS). This study demonstrates a new efficient technique for 3D printing with PDMS by using a capillary suspension ink containing PDMS in the form of both precured microbeads and uncured liquid precursor, dispersed in water as continuous medium. The PDMS microbeads are held together in thixotropic granular paste by capillary attraction induced by the liquid precursor. These capillary suspensions possess high storage moduli and yield stresses that are needed for direct ink writing. They could be 3D printed and cured both in air and under water. The resulting PDMS structures are remarkably elastic, flexible, and extensible. As the ink is made of porous, biocompatible silicone that can be printed directly inside aqueous medium, it can be used in 3D printed biomedical products, or in applications such as direct printing of bioscaffolds on live tissue. This study demonstrates a number of examples using the high softness, elasticity, and resilience of these 3D printed structures.
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Affiliation(s)
- Sangchul Roh
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Dishit P Parekh
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Bhuvnesh Bharti
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Simeon D Stoyanov
- Physical Chemistry and Soft Matter, Wageningen University, Wageningen, 6708, WE, The Netherlands
- Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
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Chang D, Fox R, Hicks E, Ferguson R, Chang K, Osborne D, Hu W, Velev OD. Investigation of interfacial properties of pure and mixed poloxamers for surfactant-mediated shear protection of mammalian cells. Colloids Surf B Biointerfaces 2017; 156:358-365. [DOI: 10.1016/j.colsurfb.2017.05.040] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 05/10/2017] [Accepted: 05/13/2017] [Indexed: 11/27/2022]
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Bernal OI, Bharti B, Flickinger MC, Velev OD. Fabrication of Photoreactive Biocomposite Coatings via Electric Field-Assisted Assembly of Cyanobacteria. Langmuir 2017; 33:5304-5313. [PMID: 28481540 DOI: 10.1021/acs.langmuir.7b00335] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We report how dielectrophoresis (DEP) can be used as a tool for the fabrication of biocomposite coatings of photoreactive cyanobacteria (Synechococcus PCC7002) on flexible polyester sheets (PEs). The PE substrates were precoated by a layer-by-layer assembled film of charged polyelectrolytes. In excellent agreement between experimental data and numerical simulations, the directed assembly process driven by external electric field results in the formation of 1D chains and 2D sheets by the cells. The preassembled cyanobacteria chains and arrays became deposited on the substrate and remained in place after the electric field was turned off due to the electrostatic attraction between the negatively charged cell surfaces and the positively charged polyelectrolyte-coated PE. The DEP-assisted packing of cyanobacteria is close to the maximal surface coverage of ∼70% estimated from convectively assembled monolayers. Confocal laser scanning microscopy and spectrophotometry confirm that the photosynthetic pigment integrity of the Synechococcus cells is preserved after DEP immobilization. The significant decrease of the light scattering and the enhanced transmittance of these field-assembled cyanobacteria coatings demonstrate reduced self-shading compared to suspension cultures. Thus, we achieved the assembly of structured cyanobacteria coatings that optimize cell surface coverage and preserve cell viability after immobilization. This is a step toward the development of flexible multilayered cell-based photoabsorbing biomaterials that can serve as components of "biomimetic leaves" for utilizing solar energy to recycle CO2 into fuels or chemicals.
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Affiliation(s)
| | - Bhuvnesh Bharti
- Cain Department of Chemical Engineering, Louisiana State University , Baton Rouge, Louisiana 70803, United States
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Rutkowski DM, Velev OD, Klapp SHL, Hall CK. Simulation study on the structural properties of colloidal particles with offset dipoles. Soft Matter 2017; 13:3134-3146. [PMID: 28397900 DOI: 10.1039/c7sm00226b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A major research theme in materials science is determining how the self-assembly of new generations of colloidal particles of complex shape and surface charge is guided by their interparticle interactions. In this paper, we describe results from quasi-2D Monte Carlo simulations of systems of colloidal particles with offset transversely-oriented extended dipole-like charge distributions interacting via an intermediate-ranged Yukawa potential. The systems are cooled slowly through an annealing procedure during which the temperature is lowered in discrete steps, allowing the system to equilibrate. We perform ground state calculations for two, three and four particles at several shifts of the dipole vector from the particle center. We create state diagrams in the plane spanned by the temperature and the area fraction outlining the boundaries between fluid, string-fluid and percolated states at various values of the shift. Remarkably we find that the effective cooling rate in our simulations has an impact on the structures formed, with chains being more prevalent if the system is cooled quickly and cyclic structures more prevalent if the system is cooled slowly. As the dipole is further shifted from the center, there is an increased tendency to assemble into small cyclic structures at intermediate temperatures. These systems further self-assemble into open lattice-like arrangements at very low temperatures. The novel structures identified might be useful for photonic applications, new types of porous media for filtration and catalysis, and gel matrices with unusual properties.
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Affiliation(s)
- David M Rutkowski
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, USA.
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Schmauch MM, Mishra SR, Evans BA, Velev OD, Tracy JB. Chained Iron Microparticles for Directionally Controlled Actuation of Soft Robots. ACS Appl Mater Interfaces 2017; 9:11895-11901. [PMID: 28349697 DOI: 10.1021/acsami.7b01209] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Magnetic field-directed self-assembly of magnetic particles in chains is useful for developing directionally responsive materials for applications in soft robotics. Using materials with greater complexity allows advanced functions, while still using simple device architectures. Elastomer films containing chained magnetic microparticles were prepared through solvent casting and formed into magnetically actuated lifters, accordions, valves, and pumps. Chaining both enhances actuation and imparts a directional response. Cantilevers used as lifters were able to lift up to 50 times the mass of the polymer film. We introduce the "specific torque", the torque per field per mass of magnetic particles, as a figure of merit for assessing and comparing the performance of lifters and related devices. Devices in this work generated specific torques of 68 Nm/kgT, which is significantly higher than in previously reported actuators. Applying magnetic fields to folded accordion structures caused extension and compression, depending on the accordion's orientation. In peristaltic pumps comprised of composite tubes containing embedded chains, magnetic fields caused a section of the tube to pinch closed where the field was applied. These results will facilitate both the further development of soft robots based on chained magnetic particles and efforts to engineer materials with higher specific torque.
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Affiliation(s)
- Marissa M Schmauch
- Department of Chemistry and Biochemistry, University of Tulsa , Tulsa, Oklahoma 74104, United States
| | | | - Benjamin A Evans
- Department of Physics, Elon University , Elon, North Carolina 27244, United States
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Koo HJ, Velev OD. Design and characterization of hydrogel-based microfluidic devices with biomimetic solute transport networks. Biomicrofluidics 2017; 11:024104. [PMID: 28396708 PMCID: PMC5367088 DOI: 10.1063/1.4978617] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Accepted: 03/02/2017] [Indexed: 05/26/2023]
Abstract
Hydrogel could serve as a matrix material of new classes of solar cells and photoreactors with embedded microfluidic networks. These devices mimic the structure and function of plant leaves, which are a natural soft matter based microfluidic system. These unusual microfluidic-hydrogel devices with fluid-penetrable medium operate on the basis of convective-diffusive mechanism, where the liquid is transported between the non-connected channels via molecular permeation through the hydrogel. We define three key designs of such hydrogel devices, having linear, T-shaped, and branched channels and report results of numerical simulation of the process of their infusion with solute carried by the incoming fluid. The computational procedure takes into account both pressure-driven convection and concentration gradient-driven diffusion in the permeable gel matrix. We define the criteria for evaluation of the fluid infusion rate, uniformity, solute loss by outflow and overall performance. The T-shaped channel network was identified as the most efficient one and was improved further by investigating the effect of the channel-end secondary branches. Our parallel experimental data on the pattern of solute infusions are in excellent agreement with the simulation. These network designs can be applied to a broad range of novel microfluidic materials and soft matter devices with distributed microchannel networks.
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Affiliation(s)
- Hyung-Jun Koo
- Department of Chemical and Biomolecular Engineering, Seoul National University of Science and Technology , Seoul 139-743, South Korea
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695, USA
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Abstract
This paper describes a technique that utilizes the osmotic properties of hydrogels to passively draw fluid through a membrane and pass it along to a microfluidic network for sensing purposes. This technique may enable non-invasive collection and manipulation of sweat for biosensing. To demonstrate the concept, thin hydrogel discs equilibrated in saline or glycerol were integrated with a microfluidic device. The hydrogel interfaces with a water-permeable membrane. The high concentration of solute in the hydrogel creates an osmotic pressure difference across the membrane, driving fluid flow through the membrane and into the device. The release of solute from the hydrogel autonomously pumps the fluid into an adjacent microfluidic channel. The flowrate of liquid drawn through the membrane is controlled by the osmotic pressure of the hydrogel and its interfacial contact area with the membrane. The flowrate gradually decreases over time as the continuous influx of withdrawn fluid dilutes the concentrated solute in the hydrogel. Initial testing has shown the device can pump accurate levels of glucose across the membrane and through a microchannel to a reservoir with a glucose sensor. Sensors and electrodes can be implemented in future microfluidic devices operating on these principles to test for other bioanalytes in sweat.
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Affiliation(s)
- Tim Shay
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, USA.
| | - Michael D Dickey
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, USA.
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, USA.
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Siebman C, Velev OD, Slaveykova VI. Alternating Current-Dielectrophoresis Collection and Chaining of Phytoplankton on Chip: Comparison of Individual Species and Artificial Communities. Biosensors (Basel) 2017; 7:E4. [PMID: 28067772 PMCID: PMC5371777 DOI: 10.3390/bios7010004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 12/21/2016] [Accepted: 12/28/2016] [Indexed: 01/26/2023]
Abstract
The capability of alternating current (AC) dielectrophoresis (DEP) for on-chip capture and chaining of the three species representative of freshwater phytoplankton was evaluated. The effects of the AC field intensity, frequency and duration on the chaining efficiency and chain lengths of green alga Chlamydomonas reinhardtii, cyanobacterium Synechocystis sp. and diatom Cyclotella meneghiniana were characterized systematically. C. reinhardtii showed an increase of the chaining efficiency from 100 Hz to 500 kHz at all field intensities; C. meneghiniana presented a decrease of chaining efficiency from 100 Hz to 1 kHz followed by a significant increase from 1 kHz to 500 kHz, while Synechocystis sp. exhibited low chaining tendency at all frequencies and all field intensities. The experimentally-determined DEP response and cell alignment of each microorganism were in agreement with their effective polarizability. Mixtures of cells in equal proportion or 10-times excess of Synechocystis sp. showed important differences in terms of chaining efficiency and length of the chains compared with the results obtained when the cells were alone in suspension. While a constant degree of chaining was observed with the mixture of C. reinhardtii and C. meneghiniana, the presence of Synechocystis sp. in each mixture suppressed the formation of chains for the two other phytoplankton species. All of these results prove the potential of DEP to discriminate different phytoplankton species depending on their effective polarizability and to enable their manipulation, such as specific collection or separation in freshwater.
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Affiliation(s)
- Coralie Siebman
- Environmental Biogeochemistry and Ecotoxicology, Department F.-A. Forel for Environmental and Aquatic Sciences, Earth and Environmental Science, Faculty of Sciences, University of Geneva, 66 Boulevard Carl-Vogt, CH-1211 Genève 4, Switzerland.
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, USA.
| | - Vera I Slaveykova
- Environmental Biogeochemistry and Ecotoxicology, Department F.-A. Forel for Environmental and Aquatic Sciences, Earth and Environmental Science, Faculty of Sciences, University of Geneva, 66 Boulevard Carl-Vogt, CH-1211 Genève 4, Switzerland.
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Bharti B, Rutkowski D, Han K, Kumar AU, Hall CK, Velev OD. Capillary Bridging as a Tool for Assembling Discrete Clusters of Patchy Particles. J Am Chem Soc 2016; 138:14948-14953. [DOI: 10.1021/jacs.6b08017] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bhuvnesh Bharti
- Department
of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
- Cain
Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - David Rutkowski
- Department
of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Koohee Han
- Department
of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Aakash Umesh Kumar
- Department
of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Carol K. Hall
- Department
of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Orlin D. Velev
- Department
of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
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Bharti B, Kogler F, Hall CK, Klapp SHL, Velev OD. Multidirectional colloidal assembly in concurrent electric and magnetic fields. Soft Matter 2016; 12:7747-58. [PMID: 27537850 DOI: 10.1039/c6sm01475e] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Dipolar interactions between nano- and micron sized colloids lead to their assembly into domains with well-defined local order. The particles with a single dipole induced by an external field assemble into linear chains and clusters. However, to achieve the formation of multidirectionally organized nano- or microassemblies with tunable physical characteristics, more sophisticated interaction tools are needed. Here we demonstrate that such complex interactions can be introduced in the form of two independent, non-interacting dipoles (double-dipoles) within a microparticle. We show how this can be achieved by the simultaneous application of alternating current (AC)-electric field and uniform magnetic field to dispersions of superparamagnetic microspheres. Depending on their timing and intensity, concurrent electric and magnetic fields lead to the formation of bidirectional particle chains, colloidal networks, and discrete crystals. We investigate the mechanistic details of the assembly process, and identify and classify the non-equilibrium states formed. The morphologies of different experimental states are in excellent correlation with our theoretical predictions based on Brownian dynamics simulations combined with a structural analysis based on local energy parameters. This novel methodology of introducing and interpreting double-dipolar particle interactions may assist in the assembly of colloidal coatings, dynamically reconfigurable particle networks, and bidirectional active structures.
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Affiliation(s)
- Bhuvnesh Bharti
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
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Tian T, Blanco E, Smoukov SK, Velev OD, Velikov KP. Dissolution behaviour of ferric pyrophosphate and its mixtures with soluble pyrophosphates: Potential strategy for increasing iron bioavailability. Food Chem 2016; 208:97-102. [DOI: 10.1016/j.foodchem.2016.03.078] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 03/03/2016] [Accepted: 03/22/2016] [Indexed: 11/26/2022]
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Blanco E, Smoukov SK, Velev OD, Velikov KP. Organic-inorganic patchy particles as a versatile platform for fluid-in-fluid dispersion stabilisation. Faraday Discuss 2016; 191:73-88. [PMID: 27442153 DOI: 10.1039/c6fd00036c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We present a new class of organic-inorganic patchy particles for the efficient stabilization of Pickering foams and emulsions. Using solvent-based heterogeneous precipitation, we decorate inorganic silica particles with discrete domains of water insoluble plant protein (zein). By varying the extent of protein coverage on the silica surface, we tune the pH-dependent interactions of the particles and the interfaces. We observe an optimum foam stabilization, which is attributed to the creation of a slightly positive low effective surface potential from positively charged protein patches and the negatively charged silica surface. The effect of surface coverage on foam stability is in line with the predicted low interfacial potential of the patchy particles in water, which determines the energy of particle adsorption. In emulsions, the increase of the protein amount on the silica particles causes a progressive bridging of the oil droplets into a close-packing configuration due to gelation of the protein patches. Protein-based organic-inorganic surface heterogeneous particles represent a new versatile platform for the stabilization of fluid-in-fluid dispersions and as precursors for the assembly of advanced functional materials.
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Affiliation(s)
- E Blanco
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, USA.
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Richter AP, Bharti B, Armstrong HB, Brown JS, Plemmons D, Paunov VN, Stoyanov SD, Velev OD. Synthesis and Characterization of Biodegradable Lignin Nanoparticles with Tunable Surface Properties. Langmuir 2016; 32:6468-77. [PMID: 27268077 DOI: 10.1021/acs.langmuir.6b01088] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Lignin nanoparticles can serve as biodegradable carriers of biocidal actives with minimal environmental footprint. Here we describe the colloidal synthesis and interfacial design of nanoparticles with tunable surface properties using two different lignin precursors, Kraft (Indulin AT) lignin and Organosolv (high-purity lignin). The green synthesis process is based on flash precipitation of dissolved lignin polymer, which enabled the formation of nanoparticles in the size range of 45-250 nm. The size evolution of the two types of lignin particles is fitted on the basis of modified diffusive growth kinetics and mass balance dependencies. The surface properties of the nanoparticles are fine-tuned by coating them with a cationic polyelectrolyte, poly(diallyldimethylammonium chloride). We analyze how the colloidal stability and dispersion properties of these two types of nanoparticles vary as a function of pH and salinities. The data show that the properties of the nanoparticles are governed by the type of lignin used and the presence of polyelectrolyte surface coating. The coating allows the control of the nanoparticles' surface charge and the extension of their stability into strongly basic regimes, facilitating their potential application at extreme pH conditions.
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Affiliation(s)
- Alexander P Richter
- Department of Chemical and Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695, United States
- BENANOVA Incorporated, Raleigh, North Carolina 27606, United States
| | - Bhuvnesh Bharti
- Department of Chemical and Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695, United States
| | - Hinton B Armstrong
- Department of Chemical and Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695, United States
- BENANOVA Incorporated, Raleigh, North Carolina 27606, United States
| | - Joseph S Brown
- Department of Chemical and Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695, United States
| | - Dayne Plemmons
- Department of Chemical and Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695, United States
| | | | - Simeon D Stoyanov
- Physical Chemistry and Soft Matter, Wageningen University , 6708 PB Wageningen, The Netherlands
- Department of Mechanical Engineering, University College London , Torrington Place, London, WC1E 7JE, U.K
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695, United States
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Rutkowski DM, Velev OD, Klapp SHL, Hall CK. The effect of charge separation on the phase behavior of dipolar colloidal rods. Soft Matter 2016; 12:4932-4943. [PMID: 27151445 DOI: 10.1039/c6sm00317f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Colloids with anisotropic shape and charge distribution can assemble into a variety of structures that could find use as novel materials for optical, photonic, electronic and structural applications. Because experimental characterization of the many possible types of multi-shape and multipolar colloidal particles that could form useful structures is difficult, the search for novel colloidal materials can be enhanced by simulations of colloidal particle assembly. We have simulated a system of dipolar colloidal rods at fixed aspect ratio using discontinuous molecular dynamics (DMD) to investigate how the charge separation of an embedded dipole affects the types of assemblies that occur. Each dipolar rod is modeled as several overlapping spheres fixed in an elongated shape to represent excluded volume and two smaller, embedded spheres to represent the charges that make up the extended dipole. Large charge separations predominately form structures where the rods link head-to-tail while small charge separations predominately form structures where the rods stack side-by-side. Rods with small charge separations tend to form dense aggregates while rods with large charge separations tend to form coarse gel-like structures. Structural phase boundaries between fluid, string-fluid, and "gel" (networked) phases are mapped out and characterized as to whether they have global head-to-tail or global side-by-side order. A structural coarsening transition is observed for particles with large charge separations in which the head-tail networks thicken as temperature is lowered due to an increased tendency to form side-by-side structures. Triangularly connected networks form at small charge separations; these may be useful for encapsulating smaller particles.
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Affiliation(s)
- David M Rutkowski
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
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Morales D, Podolsky I, Mailen RW, Shay T, Dickey MD, Velev OD. Ionoprinted Multi-Responsive Hydrogel Actuators. Micromachines (Basel) 2016; 7:E98. [PMID: 30404273 PMCID: PMC6190308 DOI: 10.3390/mi7060098] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 11/23/2022]
Abstract
We report multi-responsive and double-folding bilayer hydrogel sheet actuators, whose directional bending response is tuned by modulating the solvent quality and temperature and where locally crosslinked regions, induced by ionoprinting, enable the actuators to invert their bending axis. The sheets are made multi-responsive by combining two stimuli responsive gels that incur opposing and complementary swelling and shrinking responses to the same stimulus. The lower critical solution temperature (LCST) can be tuned to specific temperatures depending on the EtOH concentration, enabling the actuators to change direction isothermally. Higher EtOH concentrations cause upper critical solution temperature (UCST) behavior in the poly(N-isopropylacrylamide) (pNIPAAm) gel networks, which can induce an amplifying effect during bilayer bending. External ionoprints reliably and repeatedly invert the gel bilayer bending axis between water and EtOH. Placing the ionoprint at the gel/gel interface can lead to opposite shape conformations, but with no clear trend in the bending behavior. We hypothesize that this is due to the ionoprint passing through the neutral axis of the bilayer during shrinking in hot water. Finally, we demonstrate the ability of the actuators to achieve shapes unique to the specific external conditions towards developing more responsive and adaptive soft actuator devices.
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Affiliation(s)
- Daniel Morales
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Igor Podolsky
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Russell W Mailen
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Timothy Shay
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Michael D Dickey
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
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Morales D, Bharti B, Dickey MD, Velev OD. Bending of Responsive Hydrogel Sheets Guided by Field-Assembled Microparticle Endoskeleton Structures. Small 2016; 12:2283-2290. [PMID: 26969914 DOI: 10.1002/smll.201600037] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 02/17/2016] [Indexed: 06/05/2023]
Abstract
Hydrogel composites that respond to stimuli can form the basis of new classes of biomimetic actuators and soft robotic components. Common latex microspheres can be assembled and patterned by AC electric fields within a soft thermoresponsive hydrogel. The field-oriented particle chains act as endoskeletal structures, which guide the macroscopic bending pattern of the actuators.
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Affiliation(s)
- Daniel Morales
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695-7905, USA
| | - Bhuvnesh Bharti
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695-7905, USA
| | - Michael D Dickey
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695-7905, USA
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695-7905, USA
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