1
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Jana S, Nevskyi O, Höche H, Trottenberg L, Siemes E, Enderlein J, Fürstenberg A, Wöll D. Local Water Content in Polymer Gels Measured with Super-Resolved Fluorescence Lifetime Imaging. Angew Chem Int Ed Engl 2024; 63:e202318421. [PMID: 38165135 DOI: 10.1002/anie.202318421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 12/21/2023] [Accepted: 01/02/2024] [Indexed: 01/03/2024]
Abstract
Water molecules play an important role in the structure, function, and dynamics of (bio-) materials. A direct access to the number of water molecules in nanoscopic volumes can thus give new molecular insights into materials and allow for fine-tuning their properties in sophisticated applications. The determination of the local water content has become possible by the finding that H2 O quenches the fluorescence of red-emitting dyes. Since deuterated water, D2 O, does not induce significant fluorescence quenching, fluorescence lifetime measurements performed in different H2 O/D2 O-ratios yield the local water concentration. We combined this effect with the recently developed fluorescence lifetime single molecule localization microscopy imaging (FL-SMLM) in order to nanoscopically determine the local water content in microgels, i.e. soft hydrogel particles consisting of a cross-linked polymer swollen in water. The change in water content of thermo-responsive microgels when changing from their swollen state at room temperature to a collapsed state at elevated temperature could be analyzed. A clear decrease in water content was found that was, to our surprise, rather uniform throughout the entire microgel volume. Only a slightly higher water content around the dye was found in the periphery with respect to the center of the swollen microgels.
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Affiliation(s)
- Sankar Jana
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52074, Aachen, Germany
| | - Oleksii Nevskyi
- Third Institute of Physics - Biophysics, Georg August University, 37077, Göttingen, Germany
| | - Hannah Höche
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52074, Aachen, Germany
| | - Leon Trottenberg
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52074, Aachen, Germany
| | - Eric Siemes
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52074, Aachen, Germany
| | - Jörg Enderlein
- Third Institute of Physics - Biophysics, Georg August University, 37077, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), Georg August University, 37077, Göttingen, Germany
| | - Alexandre Fürstenberg
- Department of Physical Chemistry and Department of Inorganic and Analytical Chemistry, University of Geneva, 1211, Geneva, Switzerland
| | - Dominik Wöll
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52074, Aachen, Germany
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2
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Akgonullu DZ, Murray BS, Connell SD, Fang Y, Linter B, Sarkar A. Synthetic and biopolymeric microgels: Review of similarities and difference in behaviour in bulk phases and at interfaces. Adv Colloid Interface Sci 2023; 320:102983. [PMID: 37690329 DOI: 10.1016/j.cis.2023.102983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 08/12/2023] [Accepted: 08/14/2023] [Indexed: 09/12/2023]
Abstract
This review discusses the current knowledge of interfacial and bulk interactions of biopolymeric microgels in relation to the well-established properties of synthetic microgels for applications as viscosity modifiers and Pickering stabilisers. We present a timeline showing the key milestones in designing microgels and their bulk/ interfacial performance. Poly(N-isopropylacrylamide) (pNIPAM) microgels have remained as the protagonist in the synthetic microgel domain whilst proteins or polysaccharides have been primarily used to fabricate biopolymeric microgels. Bulk properties of microgel dispersions are dominated by the volume fraction (ϕ) of the microgel particles, but ϕ is difficult to pinpoint, as addressed by many theoretical models. By evaluating recent experimental studies over the last five years, we find an increasing focus on the analysis of microgel elasticity as a key parameter in modulating their packing at the interfaces, within the provinces of both synthetic and biopolymeric systems. Production methods and physiochemical factors shown to influence microgel swelling in the aqueous phase can have a significant impact on their bulk as well as interfacial performance. Compared to synthetic microgels, biopolymer microgels show a greater tendency for polydispersity and aggregation and do not appear to have a core-corona structure. Comprehensive studies of biopolymeric microgels are still lacking, for example, to accurately determine their inter- and intra- particle interactions, whilst a wider variety of techniques need to be applied in order to allow comparisons to real systems of practical usage.
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Affiliation(s)
- Daisy Z Akgonullu
- Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, UK
| | - Brent S Murray
- Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, UK
| | - Simon D Connell
- Molecular and Nanoscale Physics Group, School of Physics and Astronomy, University of Leeds, UK
| | - Yuan Fang
- PepsiCo, Valhalla, New York, NY, USA
| | | | - Anwesha Sarkar
- Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, UK.
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3
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Maity S, Gaur D, Mishra B, Dubey NC, Tripathi BP. Bactericidal and biocatalytic temperature responsive microgel based self-cleaning membranes for water purification. J Colloid Interface Sci 2023; 642:129-144. [PMID: 37003009 DOI: 10.1016/j.jcis.2023.03.095] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/01/2023] [Accepted: 03/15/2023] [Indexed: 03/31/2023]
Abstract
The present study focuses on creating an antimicrobial and biocatalytic smart gating membrane by synthesizing unique core-shell microgels. The core-shell microgels are synthesized by grafting short chains of poly(ethylenimine) (PEI) onto a poly((N-isopropyl acrylamide)-co-glycidyl methacrylate)) (P(NIPAm-co-GMA)) core. Subsequently, the produced microgels are utilized as a substrate for synthesizing and stabilizing silver nanoparticles (Ag NPs) through an in-situ approach. These Ag NPs immobilized microgels are then suction filtered over a polyethylene terephthalate (PET) track-etched support to create cross-linked composite microgel membranes (CMMs). After structural and permeation characterization of the prepared CMMs, the laccase enzyme is then covalently grafted to the surface of the membrane and tested for its effectiveness in degrading Reactive red-120 dye. The laccase immobilized biocatalytic CMMs show effective degradation of the Reactive red-120 by 71%, 48%, and 34% at pH 3, 4, and 5, respectively. Furthermore, the immobilized laccase enzyme showed better activity and stability in terms of thermal, pH, and storage compared to the free laccase, leading to increased reusability. The unique combination of Ag NPs and laccase on a thermoresponsive microgel support resulted in a responsive self-cleaning membrane with excellent antimicrobial and dye degradation capabilities for environmentally friendly separation technology.
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4
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Papadopoulou-Fermeli N, Lagopati N, Pippa N, Sakellis E, Boukos N, Gorgoulis VG, Gazouli M, Pavlatou EA. Composite Nanoarchitectonics of Photoactivated Titania-Based Materials with Anticancer Properties. Pharmaceutics 2022; 15:pharmaceutics15010135. [PMID: 36678763 PMCID: PMC9864881 DOI: 10.3390/pharmaceutics15010135] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/23/2022] [Accepted: 12/26/2022] [Indexed: 01/04/2023] Open
Abstract
The synthesis of titania-based composite materials with anticancer potential under visible-light irradiation is the aim of this study. In specific, titanium dioxide (TiO2) nanoparticles (NPs) chemically modified with silver were embedded in a stimuli-responsive microgel (a crosslinked interpenetrating network (IP) network that was synthesized by poly (N-Isopropylacrylamide) and linear chains of polyacrylic acid sodium salt, forming composite particles. The ultimate goal of this research, and for our future plans, is to develop a drug-delivery system that uses optical fibers that could efficiently photoactivate NPs, targeting cancer cells. The produced Ag-TiO2 NPs, the microgel and the composite materials were characterized through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), micro-Raman spectroscopy, ultraviolet-visible spectroscopy (UV-Vis), dynamic light scattering (DLS) and transmission electron microscopy (TEM). Our results indicated that Ag-TiO2 NPs were successfully embedded within the thermoresponsive microgel. Either Ag-TiO2 NPs or the composite materials exhibited high photocatalytic degradation efficiency on the pollutant rhodamine B and significant anticancer potential under visible-light irradiation.
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Affiliation(s)
- Nefeli Papadopoulou-Fermeli
- Laboratory of General Chemistry, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, 15789 Zografou, Greece
| | - Nefeli Lagopati
- Laboratory of General Chemistry, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, 15789 Zografou, Greece
- Laboratory of Biology, Department of Basic Medical Sciences, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
- Laboratory of Histology-Embryology, Molecular Carcinogenesis Group, Department of Basic Medical Sciences, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Natassa Pippa
- Section of Pharmaceutical Technology, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, 15771 Athens, Greece
| | - Elias Sakellis
- Institute of Nanoscience and Nanotechnology, National Center for Scientific Research “Demokritos”, 15310 Agia Paraskevi, Greece
| | - Nikos Boukos
- Institute of Nanoscience and Nanotechnology, National Center for Scientific Research “Demokritos”, 15310 Agia Paraskevi, Greece
| | - Vassilis G. Gorgoulis
- Laboratory of Histology-Embryology, Molecular Carcinogenesis Group, Department of Basic Medical Sciences, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
- Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece
- Clinical Molecular Pathology, Medical School, University of Dundee, Dundee DD1 9SY, UK
- Molecular and Clinical Cancer Sciences, Manchester Cancer Research Centre, Manchester Academic Health Sciences Centre, University of Manchester, Manchester M20 4GJ, UK
- Center for New Biotechnologies and Precision Medicine, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
- Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7YH, UK
| | - Maria Gazouli
- Laboratory of Biology, Department of Basic Medical Sciences, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
- School of Science and Technology, Hellenic Open University, 26335 Patra, Greece
| | - Evangelia A. Pavlatou
- Laboratory of General Chemistry, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, 15789 Zografou, Greece
- Correspondence: ; Tel.: +30-210-772-3110
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5
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Vialetto J, Ramakrishna SN, Isa L. In situ imaging of the three-dimensional shape of soft responsive particles at fluid interfaces by atomic force microscopy. SCIENCE ADVANCES 2022; 8:eabq2019. [PMID: 36351021 PMCID: PMC9645722 DOI: 10.1126/sciadv.abq2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The reconfiguration of individual soft and deformable particles upon adsorption at a fluid interface underpins many aspects of their dynamics and interactions, ultimately regulating the properties of monolayers of relevance for applications. In this work, we demonstrate that atomic force microscopy can be used for the in situ reconstruction of the three-dimensional conformation of model poly(N-isopropylacrylamide) microgels adsorbed at an oil-water interface. We image the particle topography from both sides of the interface to characterize its in-plane deformation and to visualize the occurrence of asymmetric swelling in the two fluids. In addition, the technique enables investigating different fluid phases and particle architectures, as well as studying the effect of temperature variations on particle conformation in situ. We envisage that these results open up an exciting range of possibilities to provide microscopic insights into the single-particle behavior of soft objects at fluid interfaces and into the resulting macroscopic material properties.
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Affiliation(s)
| | | | - Lucio Isa
- Corresponding author. (J.V.); (S.N.R.); (L.I.)
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6
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Yurdasiper A, Şahiner A, Gökçe EH. Preparation of thermoresponsive triclosan poly (N-isopropylacrylamide) nanogels and evaluation of antibacterial efficacy on Cutibacterium acnes. J Drug Deliv Sci Technol 2022. [DOI: 10.1016/j.jddst.2022.103734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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7
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Scotti A, Schulte MF, Lopez CG, Crassous JJ, Bochenek S, Richtering W. How Softness Matters in Soft Nanogels and Nanogel Assemblies. Chem Rev 2022; 122:11675-11700. [PMID: 35671377 DOI: 10.1021/acs.chemrev.2c00035] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Softness plays a key role in determining the macroscopic properties of colloidal systems, from synthetic nanogels to biological macromolecules, from viruses to star polymers. However, we are missing a way to quantify what the term "softness" means in nanoscience. Having quantitative parameters is fundamental to compare different systems and understand what the consequences of softness on the macroscopic properties are. Here, we propose different quantities that can be measured using scattering methods and microscopy experiments. On the basis of these quantities, we review the recent literature on micro- and nanogels, i.e. cross-linked polymer networks swollen in water, a widely used model system for soft colloids. Applying our criteria, we address the question what makes a nanomaterial soft? We discuss and introduce general criteria to quantify the different definitions of softness for an individual compressible colloid. This is done in terms of the energetic cost associated with the deformation and the capability of the colloid to isotropically deswell. Then, concentrated solutions of soft colloids are considered. New definitions of softness and new parameters, which depend on the particle-to-particle interactions, are introduced in terms of faceting and interpenetration. The influence of the different synthetic routes on the softness of nanogels is discussed. Concentrated solutions of nanogels are considered and we review the recent results in the literature concerning the phase behavior and flow properties of nanogels both in three and two dimensions, in the light of the different parameters we defined. The aim of this review is to look at the results on micro- and nanogels in a more quantitative way that allow us to explain the reported properties in terms of differences in colloidal softness. Furthermore, this review can give researchers dealing with soft colloids quantitative methods to define unambiguously which softness matters in their compound.
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Affiliation(s)
- Andrea Scotti
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany, European Union
| | - M Friederike Schulte
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany, European Union
| | - Carlos G Lopez
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany, European Union
| | - Jérôme J Crassous
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany, European Union
| | - Steffen Bochenek
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany, European Union
| | - Walter Richtering
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany, European Union
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8
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Schulte MF, Izak-Nau E, Braun S, Pich A, Richtering W, Göstl R. Microgels react to force: mechanical properties, syntheses, and force-activated functions. Chem Soc Rev 2022; 51:2939-2956. [PMID: 35319064 DOI: 10.1039/d2cs00011c] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Microgels are colloidal polymer networks with high molar mass and properties between rigid particles, flexible macromolecules, and micellar aggregates. Their unique stimuli-responsiveness in conjunction with their colloidal phase behavior render them useful for many applications ranging from engineering to biomedicine. In many scenarios either the microgel's mechanical properties or its interactions with mechanical force play an important role. Here, we firstly explain microgel mechanical properties and how these are measured by atomic force microscopy (AFM), then we equip the reader with the synthetic background to understand how specific architectures and chemical functionalities enable these mechanical properties, and eventually we elucidate how the interaction of force with microgels can lead to the activation of latent functionality. Since the interaction of microgels with force is a multiscale and multidisciplinary subject, we introduce and interconnect the different research areas that contribute to the understanding of this emerging field in this Tutorial Review.
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Affiliation(s)
- M Friederike Schulte
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany.
| | - Emilia Izak-Nau
- DWI - Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52056 Aachen, Germany.
| | - Susanne Braun
- DWI - Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52056 Aachen, Germany. .,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Andrij Pich
- DWI - Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52056 Aachen, Germany. .,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.,Maastricht University, Aachen Maastricht Institute for Biobased Materials (AMIBM), Brightlands Chemelot Campus, 6167 RD Geleen, The Netherlands
| | - Walter Richtering
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany.
| | - Robert Göstl
- DWI - Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52056 Aachen, Germany.
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9
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Santi M, Saha P, Walkowiak JJ, Rubner J, Wessling M, Pich A. In-Line Characterization of the Temperature-Responsive Behavior of Surface-Bound Microgel Coatings by QCM-D: A Novel Strategy for Protein Repellence Evaluation. ACS APPLIED MATERIALS & INTERFACES 2022; 14:10907-10916. [PMID: 35179345 DOI: 10.1021/acsami.1c21814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In this work, quartz crystal microbalance with dissipation monitoring (QCM-D) was used to develop a new method to evaluate the protein repellency of microgel coatings. Compared to traditional protocols for surface analysis, QCM has the advantage of a real-time quantitative approach with high sensitivity, allowing us to describe variations of the adsorbed mass with unprecedented accuracy. To enable the detectability of the film throughout the whole operational temperature interval, a poly(N-isopropylacrylamide-co-glycidyl methacrylate) p(NIPAm-co-GMA) microgel monolayer with defined thickness and rigidity was designed. Covalent adhesion of the film to the silica surface was achieved by epoxy-thiol click chemistry and tested for repeated temperature cycles, showing substantial reproducibility. Further functionalization of microgel surfaces by grafting polyzwitterionic chains remarkably improved the protein repellence leaving the strong surface adhesion unaltered. Before and after exposure to fluorescein-tagged bovine serum albumin (FITC-BSA), the coatings showed identical responsive behavior, proving the absence of protein deposition. In nonrepellent coatings, QCM monitoring instead displayed a characteristic shift in the volume phase transition (VPT), pointing out the effect of adsorbed proteins on the swelling behavior of pNIPAm. The combination of QCM-D and UV-visible (UV-vis) was used to evaluate the effect of increasing surface coverage, enabling to distinguish between the protein deposition occurring over the coated and the uncoated portion of the sensor.
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Affiliation(s)
- Marta Santi
- DWI - Leibniz-Institute for Interactive Materials, Aachen 52074, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Aachen 52074, Germany
| | - Pabitra Saha
- DWI - Leibniz-Institute for Interactive Materials, Aachen 52074, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Aachen 52074, Germany
| | - Jacek Janusz Walkowiak
- DWI - Leibniz-Institute for Interactive Materials, Aachen 52074, Germany
- Aachen Maastricht Institute for Biobased Materials (AMIBM), Maastricht University, Geleen 6167 RD, the Netherlands
| | - Jens Rubner
- Chemical Process Engineering AVT.CVT, RWTH Aachen University, Aachen 52074, Germany
| | - Matthias Wessling
- DWI - Leibniz-Institute for Interactive Materials, Aachen 52074, Germany
- Chemical Process Engineering AVT.CVT, RWTH Aachen University, Aachen 52074, Germany
| | - Andrij Pich
- DWI - Leibniz-Institute for Interactive Materials, Aachen 52074, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Aachen 52074, Germany
- Aachen Maastricht Institute for Biobased Materials (AMIBM), Maastricht University, Geleen 6167 RD, the Netherlands
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10
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Li G, Varga I, Kardos A, Dobryden I, Claesson PM. Nanoscale Mechanical Properties of Core-Shell-like Poly-NIPAm Microgel Particles: Effect of Temperature and Cross-Linking Density. J Phys Chem B 2021; 125:9860-9869. [PMID: 34428041 DOI: 10.1021/acs.jpcb.1c04173] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Poly-NIPAm microgel particles with two different cross-linking densities were prepared with the classical batch polymerization process. These particles were adsorbed onto modified silica surfaces, and their nanomechanical properties were measured by means of atomic force microscopy. It was found that these particles have a hard core-soft shell structure both below and above the volume transition temperature. The core-shell-like structure appears due to a higher reaction rate of the cross-linker compared to that of the monomer, leading to depletion of cross-linker in the shell region. The microgel beads with lower average cross-linking density were found to be less stiff below the volume transition temperature than the microgel with higher cross-linking density. Increasing the temperature further to just above the volume transition temperature led to lower stiffness of the more highly cross-linked microgel compared to its less cross-linked counterpart. This effect is explained with the more gradual deswelling with temperature for the more cross-linked microgel particles. This phenomenon was confirmed by dynamic light scattering measurements in the bulk phase, which showed that the larger cross-linking density microgel showed a more gradual collapse in aqueous solution as the temperature was increased.
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Affiliation(s)
- Gen Li
- Biotechnology and Health, Department of Chemistry, Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
| | - Imre Varga
- Institute of Chemistry, Eötvös Loránd University, Pázmány P. s. 1/A, 1117 Budapest, Hungary.,Department of Chemistry, University J. Selyeho, 945 01 Komarno, Slovakia
| | - Attila Kardos
- Institute of Chemistry, Eötvös Loránd University, Pázmány P. s. 1/A, 1117 Budapest, Hungary.,Department of Chemistry, University J. Selyeho, 945 01 Komarno, Slovakia
| | - Illia Dobryden
- Biotechnology and Health, Department of Chemistry, Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden.,Department of Engineering Sciences and Mathematics, Division of Materials Science, Luleå University of Technology, 97187 Luleå, Sweden
| | - Per M Claesson
- Biotechnology and Health, Department of Chemistry, Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden.,Division of Bioscience and Materials, RISE Research Institutes of Sweden, Box 5607, SE 114 86 Stockholm, Sweden
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11
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Wilms D, Adler Y, Schröer F, Bunnemann L, Schmidt S. Elastic modulus distribution in poly( N-isopopylacrylamide) and oligo(ethylene glycol methacrylate)-based microgels studied by AFM. SOFT MATTER 2021; 17:5711-5717. [PMID: 34013309 DOI: 10.1039/d1sm00291k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The spatial elastic modulus distribution of microgel networks in presence and absence of bifunctional crosslinkers is studied by AFM. Thermoresponsive poly(N-isopopylacrylamide) (PNIPAM) and poly(2-(2-methoxyethoxy)ethyl methacrylate-co-oligo(ethylene glycol)methacrylate) (P(MEO2MA-co-OEGMA)) microgels are synthesized via precipitation polymerization above their lower critical solution temperature (LCST). High-resolution elastic modulus profiles are acquired using AFM force-indentation mapping of surface-deposited microgels at 25 °C. For both microgel systems, the use of a bifunctional crosslinker leads to a strong elastic modulus gradient with stiff microgel cores and soft networks toward the edge. In absence of a dedicated crosslinker (self-crosslinking), PNIPAM microgels show a homogeneous elastic modulus distribution, whereas self-crosslinked P(MEO2MA-co-OEGMA) microgels still show decreasing elastic moduli from the centre to the edge of the microgels. However, POEGMA microgels without comonomer showed no elastic modulus gradient suggesting that different incorporation rates of MEO2MA and OEGMA result in a radial variation of the polymer segment density. In addition, when varying the molecular weight of OEGMA the overall elastic modulus was affected, possibly due to molecular weight-dependent phase behavior and different reactivity. This shows that quite different microgel architectures can be obtained by the simple "one-pot" precipitation reaction of microgels which may open to new avenues toward advanced applications.
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Affiliation(s)
- Dimitri Wilms
- Institute for Organic Chemistry and Macromolecular Chemistry, Heinrich-Heine-University, Universitätsstr. 1, 40225 Düsseldorf, Germany.
| | - Yanik Adler
- Institute for Organic Chemistry and Macromolecular Chemistry, Heinrich-Heine-University, Universitätsstr. 1, 40225 Düsseldorf, Germany.
| | - Fabian Schröer
- Institute for Organic Chemistry and Macromolecular Chemistry, Heinrich-Heine-University, Universitätsstr. 1, 40225 Düsseldorf, Germany.
| | - Lennart Bunnemann
- Institute for Organic Chemistry and Macromolecular Chemistry, Heinrich-Heine-University, Universitätsstr. 1, 40225 Düsseldorf, Germany.
| | - Stephan Schmidt
- Institute for Organic Chemistry and Macromolecular Chemistry, Heinrich-Heine-University, Universitätsstr. 1, 40225 Düsseldorf, Germany.
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12
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Oevreeide IH, Szydlak R, Luty M, Ahmed H, Prot V, Skallerud BH, Zemła J, Lekka M, Stokke BT. On the Determination of Mechanical Properties of Aqueous Microgels-Towards High-Throughput Characterization. Gels 2021; 7:64. [PMID: 34072792 PMCID: PMC8261632 DOI: 10.3390/gels7020064] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/21/2021] [Accepted: 05/25/2021] [Indexed: 12/15/2022] Open
Abstract
Aqueous microgels are distinct entities of soft matter with mechanical signatures that can be different from their macroscopic counterparts due to confinement effects in the preparation, inherently made to consist of more than one domain (Janus particles) or further processing by coating and change in the extent of crosslinking of the core. Motivated by the importance of the mechanical properties of such microgels from a fundamental point, but also related to numerous applications, we provide a perspective on the experimental strategies currently available and emerging tools being explored. Albeit all techniques in principle exploit enforcing stress and observing strain, the realization differs from directly, as, e.g., by atomic force microscope, to less evident in a fluid field combined with imaging by a high-speed camera in high-throughput strategies. Moreover, the accompanying analysis strategies also reflect such differences, and the level of detail that would be preferred for a comprehensive understanding of the microgel mechanical properties are not always implemented. Overall, the perspective is that current technologies have the capacity to provide detailed, nanoscopic mechanical characterization of microgels over an extended size range, to the high-throughput approaches providing distributions over the mechanical signatures, a feature not readily accessible by atomic force microscopy and micropipette aspiration.
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Affiliation(s)
- Ingrid Haga Oevreeide
- Biophysics and Medical Technology, Department of Physics, NTNU The Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; (I.H.O.); (H.A.)
| | - Renata Szydlak
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland; (R.S.); (M.L.); (J.Z.)
| | - Marcin Luty
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland; (R.S.); (M.L.); (J.Z.)
| | - Husnain Ahmed
- Biophysics and Medical Technology, Department of Physics, NTNU The Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; (I.H.O.); (H.A.)
| | - Victorien Prot
- Biomechanics, Department of Structural Engineering, NTNU The Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; (V.P.); (B.H.S.)
| | - Bjørn Helge Skallerud
- Biomechanics, Department of Structural Engineering, NTNU The Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; (V.P.); (B.H.S.)
| | - Joanna Zemła
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland; (R.S.); (M.L.); (J.Z.)
| | - Małgorzata Lekka
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland; (R.S.); (M.L.); (J.Z.)
| | - Bjørn Torger Stokke
- Biophysics and Medical Technology, Department of Physics, NTNU The Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; (I.H.O.); (H.A.)
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