1
|
Kurdadze T, Lamadie F, Nehme KA, Teychené S, Biscans B, Rodriguez-Ruiz I. On-Chip Photonic Detection Techniques for Non-Invasive In Situ Characterizations at the Microfluidic Scale. SENSORS (BASEL, SWITZERLAND) 2024; 24:1529. [PMID: 38475065 DOI: 10.3390/s24051529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 02/21/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024]
Abstract
Microfluidics has emerged as a robust technology for diverse applications, ranging from bio-medical diagnostics to chemical analysis. Among the different characterization techniques that can be used to analyze samples at the microfluidic scale, the coupling of photonic detection techniques and on-chip configurations is particularly advantageous due to its non-invasive nature, which permits sensitive, real-time, high throughput, and rapid analyses, taking advantage of the microfluidic special environments and reduced sample volumes. Putting a special emphasis on integrated detection schemes, this review article explores the most relevant advances in the on-chip implementation of UV-vis, near-infrared, terahertz, and X-ray-based techniques for different characterizations, ranging from punctual spectroscopic or scattering-based measurements to different types of mapping/imaging. The principles of the techniques and their interest are discussed through their application to different systems.
Collapse
Affiliation(s)
- Tamar Kurdadze
- CEA, DES, ISEC, DMRC, Univ Montpellier, 30207 Bagnols-sur-Ceze, Marcoule, France
| | - Fabrice Lamadie
- CEA, DES, ISEC, DMRC, Univ Montpellier, 30207 Bagnols-sur-Ceze, Marcoule, France
| | - Karen A Nehme
- Laboratoire de Génie Chimique, CNRS, UMR 5503, 4 Allée Emile Monso, 31432 Toulouse, France
| | - Sébastien Teychené
- Laboratoire de Génie Chimique, CNRS, UMR 5503, 4 Allée Emile Monso, 31432 Toulouse, France
| | - Béatrice Biscans
- Laboratoire de Génie Chimique, CNRS, UMR 5503, 4 Allée Emile Monso, 31432 Toulouse, France
| | - Isaac Rodriguez-Ruiz
- Laboratoire de Génie Chimique, CNRS, UMR 5503, 4 Allée Emile Monso, 31432 Toulouse, France
| |
Collapse
|
2
|
Torquato LMG, Hélaine N, Cui Y, O'Connell R, Gummel J, Robles ESJ, Jacob D, Cabral JT. Microfluidic in-line dynamic light scattering with a commercial fibre optic system. LAB ON A CHIP 2023; 23:2540-2552. [PMID: 37185587 DOI: 10.1039/d3lc00062a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We report the coupling of dynamic light scattering (DLS) in microfluidics, using a contact-free fibre-optic system, enabling the under-flow characterisation of a range of solutions, dispersions, and structured fluids. The system is evaluated and validated with model systems, specifically micellar and (dilute) polymer solutions, and colloidal dispersions of different radii (∼1-100 nm). A systematic method of flow-DLS analysis is examined as a function of flow velocity (0-16 cm s-1), and considerations of the relative contribution of 'transit' and 'Brownian' terms enable the identification of regions where (i) a quiescent approximation suffices, (ii) the flow-DLS framework holds, as well as (iii) where deviations are found, until eventually (iv) the convection dominates. We investigate practically relevant, robust setups, namely that of a capillary connected to microdevice, as well as direct measurement on a glass microdevice, examining the role of capillary dimensions and challenges of optical alignment. We conclude with a demonstration of a continuous flow measurement of a binary surfactant/salt solution, whose micellar dimensions vary with composition, characterised with hundreds of data points (every ∼5 s) and adequate statistics, within a few minutes.
Collapse
Affiliation(s)
- Luis M G Torquato
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
| | - Nelson Hélaine
- CNRS UMR 5623, Laboratoire des IMRCP, Universite Paul Sabatier, Toulouse, France
| | - Yufan Cui
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
| | - Roisin O'Connell
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
| | - Jérémie Gummel
- Procter & Gamble, Brussels Innovation Centre, Temselaan 100, 1853 Strombeek-Bever, Belgium
| | - Eric S J Robles
- Procter & Gamble, Newcastle Innovation Centre, Newcastle upon Tyne NE12 9TS, UK
| | - David Jacob
- Cordouan Technologies, 11 Avenue Canteranne, 33600 Pessac, France
| | - João T Cabral
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
| |
Collapse
|
3
|
Volk AA, Campbell ZS, Ibrahim MYS, Bennett JA, Abolhasani M. Flow Chemistry: A Sustainable Voyage Through the Chemical Universe en Route to Smart Manufacturing. Annu Rev Chem Biomol Eng 2022; 13:45-72. [PMID: 35259931 DOI: 10.1146/annurev-chembioeng-092120-024449] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microfluidic devices and systems have entered many areas of chemical engineering, and the rate of their adoption is only increasing. As we approach and adapt to the critical global challenges we face in the near future, it is important to consider the capabilities of flow chemistry and its applications in next-generation technologies for sustainability, energy production, and tailor-made specialty chemicals. We present the introduction of microfluidics into the fundamental unit operations of chemical engineering. We discuss the traits and advantages of microfluidic approaches to different reactive systems, both well-established and emerging, with a focus on the integration of modular microfluidic devices into high-efficiency experimental platforms for accelerated process optimization and intensified continuous manufacturing. Finally, we discuss the current state and new horizons in self-driven experimentation in flow chemistry for both intelligent exploration through the chemical universe and distributed manufacturing. Expected final online publication date for the Annual Review of Chemical and Biomolecular Engineering, Volume 13 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Amanda A Volk
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA; , , , ,
| | - Zachary S Campbell
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA; , , , ,
| | - Malek Y S Ibrahim
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA; , , , ,
| | - Jeffrey A Bennett
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA; , , , ,
| | - Milad Abolhasani
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA; , , , ,
| |
Collapse
|
4
|
Onofri FRA, Rodriguez-Ruiz I, Lamadie F. Microfluidic lab-on-a-chip characterization of nano- to microparticles suspensions by light extinction spectrometry. OPTICS EXPRESS 2022; 30:2981-2990. [PMID: 35209427 DOI: 10.1364/oe.444044] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/24/2021] [Indexed: 06/14/2023]
Abstract
The analysis of nano- and microparticle suspensions with micro systems affords improved space-time yields, selectivity, reaction residence times and conversions capabilities. These capabilities are of primary importance in various fields of research and industry. The few microfluidic lab-on-a-chip approaches that have been developed are essentially designed to analyse fluid phases or involve the use of benchtop particle sizing instruments. We report a novel microscale approach to characterize the particle size distribution and absolute concentration of colloidal suspensions. The method is based on a photonic lab-on-a-chip with three scale-specific detection channels to record simultaneous light extinction spectra. Experiments carried out on particle standards with sizes ranging from 30 nm to 0.5 µm and volume concentrations of 1 to 1000ppm, clearly demonstrate the value and potential of the proposed method.
Collapse
|
5
|
Volk AA, Epps RW, Abolhasani M. Accelerated Development of Colloidal Nanomaterials Enabled by Modular Microfluidic Reactors: Toward Autonomous Robotic Experimentation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2004495. [PMID: 33289177 DOI: 10.1002/adma.202004495] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/03/2020] [Indexed: 05/09/2023]
Abstract
In recent years, microfluidic technologies have emerged as a powerful approach for the advanced synthesis and rapid optimization of various solution-processed nanomaterials, including semiconductor quantum dots and nanoplatelets, and metal plasmonic and reticular framework nanoparticles. These fluidic systems offer access to previously unattainable measurements and synthesis conditions at unparalleled efficiencies and sampling rates. Despite these advantages, microfluidic systems have yet to be extensively adopted by the colloidal nanomaterial community. To help bridge the gap, this progress report details the basic principles of microfluidic reactor design and performance, as well as the current state of online diagnostics and autonomous robotic experimentation strategies, toward the size, shape, and composition-controlled synthesis of various colloidal nanomaterials. By discussing the application of fluidic platforms in recent high-priority colloidal nanomaterial studies and their potential for integration with rapidly emerging artificial intelligence-based decision-making strategies, this report seeks to encourage interdisciplinary collaborations between microfluidic reactor engineers and colloidal nanomaterial chemists. Full convergence of these two research efforts offers significantly expedited and enhanced nanomaterial discovery, optimization, and manufacturing.
Collapse
Affiliation(s)
- Amanda A Volk
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC, 27695, USA
| | - Robert W Epps
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC, 27695, USA
| | - Milad Abolhasani
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC, 27695, USA
| |
Collapse
|
6
|
Abstract
Focus a laser on dissolved particles and analyze the scattered light to reveal their size. This well established principle is used in dynamic light scattering (DLS), or also called photon-correlation spectroscopy, which is a widely popular and highly adaptable analytical method applied in different fields of life and material sciences, as well as in industrial quality control processes.
Collapse
Affiliation(s)
- Alice S. Pereira
- grid.10772.330000000121511713Molecular Biophysics Lab., UCIBIO/Requimte, Department of Chemistry, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Pedro Tavares
- grid.10772.330000000121511713Molecular Biophysics Lab., UCIBIO/Requimte, Department of Chemistry, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Paulo Limão-Vieira
- grid.10772.330000000121511713Atomic and Molecular Collisions Laboratory, CEFITEC, Department of Physics, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| |
Collapse
|
7
|
Bolze H, Erfle P, Riewe J, Bunjes H, Dietzel A, Burg TP. A Microfluidic Split-Flow Technology for Product Characterization in Continuous Low-Volume Nanoparticle Synthesis. MICROMACHINES 2019; 10:mi10030179. [PMID: 30857317 PMCID: PMC6470898 DOI: 10.3390/mi10030179] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 02/26/2019] [Accepted: 03/05/2019] [Indexed: 12/31/2022]
Abstract
A key aspect of microfluidic processes is their ability to perform chemical reactions in small volumes under continuous flow. However, a continuous process requires stable reagent flow over a prolonged period. This can be challenging in microfluidic systems, as bubbles or particles easily block or alter the flow. Online analysis of the product stream can alleviate this problem by providing a feedback signal. When this signal exceeds a pre-defined range, the process can be re-adjusted or interrupted to prevent contamination. Here we demonstrate the feasibility of this concept by implementing a microfluidic detector downstream of a segmented-flow system for the synthesis of lipid nanoparticles. To match the flow rate through the detector to the measurement bandwidth independent of the synthesis requirements, a small stream is sidelined from the original product stream and routed through a measuring channel with 2 × 2 µm cross-section. The small size of the measuring channel prevents the entry of air plugs, which are inherent to our segmented flow synthesis device. Nanoparticles passing through the small channel were detected and characterized by quantitative fluorescence measurements. With this setup, we were able to count single nanoparticles. This way, we were able to detect changes in the particle synthesis affecting the size, concentration, or velocity of the particles in suspension. We envision that the flow-splitting scheme demonstrated here can be transferred to detection methods other than fluorescence for continuous monitoring and feedback control of microfluidic nanoparticle synthesis.
Collapse
Affiliation(s)
- Holger Bolze
- Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany.
- Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Braunschweig 38106, Germany.
| | - Peer Erfle
- Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Braunschweig 38106, Germany.
- Institute of Microtechnology, Technische Universität Braunschweig, Braunschweig 38124, Germany.
| | - Juliane Riewe
- Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Braunschweig 38106, Germany.
- Institut für Pharmazeutische Technologie, Technische Universität Braunschweig, Braunschweig 38106, Germany.
| | - Heike Bunjes
- Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Braunschweig 38106, Germany.
- Institut für Pharmazeutische Technologie, Technische Universität Braunschweig, Braunschweig 38106, Germany.
| | - Andreas Dietzel
- Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Braunschweig 38106, Germany.
- Institute of Microtechnology, Technische Universität Braunschweig, Braunschweig 38124, Germany.
| | - Thomas P Burg
- Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany.
- Department of Electrical Engineering and Information Technology, Technische Universität Darmstadt, 64283 Darmstadt, Germany.
| |
Collapse
|
8
|
Abdellatif AA, Abou-Taleb HA, Abd El Ghany AA, Lutz I, Bouazzaoui A. Targeting of somatostatin receptors expressed in blood cells using quantum dots coated with vapreotide. Saudi Pharm J 2018; 26:1162-1169. [PMID: 30532637 PMCID: PMC6260484 DOI: 10.1016/j.jsps.2018.07.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 07/19/2018] [Indexed: 12/27/2022] Open
Abstract
Cancer may be difficult to target, however, if cancer targeted this provides the chance for a better and more effective treatment. Quantum dots (Qdots) coated vapreotide (VAP) as a somatostatin receptors (SSTRs) agonist can be efficient targeting issue since may reduce side effects and increase drug delivery to the target tissue. This study highlights the active targeting of cancer cells by cells imaging with improving the therapeutic outcomes. VAP was conjugated to Qdots using amine-to-sulfhydryl crosslinker. The synthesized Qdots-VAP was characterized by determination of size, measuring the zeta-potential and UV fluorometer. The cellular uptake was studied using different cell lines. Finally, the Qdots-VAP was injected into a rat model. The results showed a size of 479.8 ± 15 and 604.88 ± 17 nm for unmodified Qdots and Qdots-VAP respectively, while the zeta potential of particles went from negative to positive charge which proved the conjugation of VAP to Qdots. The fluorometer recorded a redshift for Qdots-VAP compared with unmodified Qdots. Moreover, cellular uptake exhibited high specific binding with cells which express SSTRs using confocal microscopy and flow cytometry (17.3 MFU comparing to 3.1 MFU of control, P < 0.001). Finally, an in vivo study showed a strong accumulation of Qdots-VAP in the blood cells (70%). In conclusion, Qdots-VAP can play a crucial role in cancer diagnosis and treatment of blood cells diseases when conjugated with VAP as SSTRs agonist.
Collapse
Affiliation(s)
- Ahmed A.H. Abdellatif
- Pharmaceutics and Industrial Pharmacy Department, Faculty of Pharmacy, Al-Azhar University, 71524 Assiut, Egypt
- Pharmaceutics Department, Faculty of Pharmacy, Qassim University, 51452 Buraydah, Saudi Arabia
| | - Heba A. Abou-Taleb
- Pharmaceutics and Industrial Pharmacy Department, Faculty of Pharmacy, Nahda University (NUB), Benisuef, Egypt
| | | | - Ilka Lutz
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Mueggelseedamm 301, 12587 Berlin, Germany
| | - Abdellatif Bouazzaoui
- Science and Technology Unit, Umm Al Qura University, Makkah 21955, Saudi Arabia
- Internal Medicine 3-Hematology/Oncology Department, University Medical Center, Regensburg, Germany
| |
Collapse
|
9
|
Rifaie-Graham O, Hua X, Bruns N, Balog S. The Kinetics of β-Hematin Crystallization Measured by Depolarized Light Scattering. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1802295. [PMID: 30176111 DOI: 10.1002/smll.201802295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/05/2018] [Indexed: 06/08/2023]
Abstract
Malaria is caused by Plasmodium sp. parasites transmitted by infected female Anopheles sp. mosquitoes. The survival of the parasites in the host relies on detoxifying free heme by biocrystallization into insoluble crystals called hemozoin. This mechanism of self-preservation is targeted by a certain class of antimalarial drugs, which are screened and selected based on their capacity to inhibit the formation of hemozoin crystals. Therefore, experimental techniques capable of accurately characterizing the kinetics of crystal formation are valuable. Relying on the optical anisotropy of hemozoin, the kinetics of β-hematin crystal formation through the statistical analysis of photon counts of dynamic depolarized light scattering (DDLS), in the absence and presence of an antimalarial drug (chloroquine, CQ), is described. It is found that CQ has an impact on both the nucleation and growth of the crystals.
Collapse
Affiliation(s)
- Omar Rifaie-Graham
- Adolphe Merkle Institute, University of Fribourg, Chemin des, Verdiers 4,1700, Fribourg, Switzerland
| | - Xiao Hua
- Adolphe Merkle Institute, University of Fribourg, Chemin des, Verdiers 4,1700, Fribourg, Switzerland
| | - Nico Bruns
- Adolphe Merkle Institute, University of Fribourg, Chemin des, Verdiers 4,1700, Fribourg, Switzerland
| | - Sandor Balog
- Adolphe Merkle Institute, University of Fribourg, Chemin des, Verdiers 4,1700, Fribourg, Switzerland
| |
Collapse
|
10
|
|
11
|
Kopp MR, Arosio P. Microfluidic Approaches for the Characterization of Therapeutic Proteins. J Pharm Sci 2018; 107:1228-1236. [DOI: 10.1016/j.xphs.2018.01.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Revised: 12/01/2017] [Accepted: 01/03/2018] [Indexed: 01/31/2023]
|
12
|
Gicquel Y, Schubert R, Kapis S, Bourenkov G, Schneider T, Perbandt M, Betzel C, Chapman HN, Heymann M. Microfluidic Chips for In Situ Crystal X-ray Diffraction and In Situ Dynamic Light Scattering for Serial Crystallography. J Vis Exp 2018. [PMID: 29757285 PMCID: PMC6100780 DOI: 10.3791/57133] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
This protocol describes fabricating microfluidic devices with low X-ray background optimized for goniometer based fixed target serial crystallography. The devices are patterned from epoxy glue using soft lithography and are suitable for in situ X-ray diffraction experiments at room temperature. The sample wells are lidded on both sides with polymeric polyimide foil windows that allow diffraction data collection with low X-ray background. This fabrication method is undemanding and inexpensive. After the sourcing of a SU-8 master wafer, all fabrication can be completed outside of a cleanroom in a typical research lab environment. The chip design and fabrication protocol utilize capillary valving to microfluidically split an aqueous reaction into defined nanoliter sized droplets. This loading mechanism avoids the sample loss from channel dead-volume and can easily be performed manually without using pumps or other equipment for fluid actuation. We describe how isolated nanoliter sized drops of protein solution can be monitored in situ by dynamic light scattering to control protein crystal nucleation and growth. After suitable crystals are grown, complete X-ray diffraction datasets can be collected using goniometer based in situ fixed target serial X-ray crystallography at room temperature. The protocol provides custom scripts to process diffraction datasets using a suite of software tools to solve and refine the protein crystal structure. This approach avoids the artefacts possibly induced during cryo-preservation or manual crystal handling in conventional crystallography experiments. We present and compare three protein structures that were solved using small crystals with dimensions of approximately 10-20 µm grown in chip. By crystallizing and diffracting in situ, handling and hence mechanical disturbances of fragile crystals is minimized. The protocol details how to fabricate a custom X-ray transparent microfluidic chip suitable for in situ serial crystallography. As almost every crystal can be used for diffraction data collection, these microfluidic chips are a very efficient crystal delivery method.
Collapse
Affiliation(s)
- Yannig Gicquel
- Center for Free Electron Laser Science, DESY; Department of Physics, University of Hamburg
| | - Robin Schubert
- Institute for Biochemistry and Molecular Biology, Laboratory for Structural Biology of Infection and Inflammation, University of Hamburg; The Hamburg Center for Ultrafast Imaging, University of Hamburg; Integrated Biology Infrastructure Life-Science Facility at the European XFEL (XBI)
| | - Svetlana Kapis
- Institute for Biochemistry and Molecular Biology, Laboratory for Structural Biology of Infection and Inflammation, University of Hamburg
| | | | | | - Markus Perbandt
- Institute for Biochemistry and Molecular Biology, Laboratory for Structural Biology of Infection and Inflammation, University of Hamburg; The Hamburg Center for Ultrafast Imaging, University of Hamburg
| | - Christian Betzel
- Institute for Biochemistry and Molecular Biology, Laboratory for Structural Biology of Infection and Inflammation, University of Hamburg; The Hamburg Center for Ultrafast Imaging, University of Hamburg; Integrated Biology Infrastructure Life-Science Facility at the European XFEL (XBI)
| | - Henry N Chapman
- Center for Free Electron Laser Science, DESY; Department of Physics, University of Hamburg; The Hamburg Center for Ultrafast Imaging, University of Hamburg
| | - Michael Heymann
- Center for Free Electron Laser Science, DESY; Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry;
| |
Collapse
|
13
|
Falke S, Dierks K, Blanchet C, Graewert M, Cipriani F, Meijers R, Svergun D, Betzel C. Multi-channel in situ dynamic light scattering instrumentation enhancing biological small-angle X-ray scattering experiments at the PETRA III beamline P12. JOURNAL OF SYNCHROTRON RADIATION 2018; 25:361-372. [PMID: 29488914 DOI: 10.1107/s1600577517017568] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 12/07/2017] [Indexed: 06/08/2023]
Abstract
Small-angle X-ray scattering (SAXS) analysis of biomolecules is increasingly common with a constantly high demand for comprehensive and efficient sample quality control prior to SAXS experiments. As monodisperse sample suspensions are desirable for SAXS experiments, latest dynamic light scattering (DLS) techniques are most suited to obtain non-invasive and rapid information about the particle size distribution of molecules in solution. A multi-receiver four-channel DLS system was designed and adapted at the BioSAXS endstation of the EMBL beamline P12 at PETRA III (DESY, Hamburg, Germany). The system allows the collection of DLS data within round-shaped sample capillaries used at beamline P12. Data obtained provide information about the hydrodynamic radius of biological particles in solution and dispersity of the solution. DLS data can be collected directly prior to and during an X-ray exposure. To match the short X-ray exposure times of around 1 s for 20 exposures at P12, the DLS data collection periods that have been used up to now of 20 s or commonly more were substantially reduced, using a novel multi-channel approach collecting DLS data sets in the SAXS sample capillary at four different neighbouring sample volume positions in parallel. The setup allows online scoring of sample solutions applied for SAXS experiments, supports SAXS data evaluation and for example indicates local inhomogeneities in a sample solution in a time-efficient manner. Biological macromolecules with different molecular weights were applied to test the system and obtain information about the performance. All measured hydrodynamic radii are in good agreement with DLS results obtained by employing a standard cuvette instrument. Moreover, applying the new multi-channel DLS setup, a reliable radius determination of sample solutions in flow, at flow rates normally used for size-exclusion chromatography-SAXS experiments, and at higher flow rates, was verified as well. This study also shows and confirms that the newly designed sample compartment with attached DLS instrumentation does not disturb SAXS measurements.
Collapse
Affiliation(s)
- Sven Falke
- Laboratory for Structural Biology of Infection and Inflammation, University Hamburg, c/o DESY, Building 22a, Notkestrasse 85, Hamburg 22603, Germany
| | - Karsten Dierks
- Xtal Concepts GmbH, Marlowring 19, Hamburg 22525, Germany
| | - Clement Blanchet
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, c/o Notkestrasse 85, Hamburg 22607, Germany
| | - Melissa Graewert
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, c/o Notkestrasse 85, Hamburg 22607, Germany
| | - Florent Cipriani
- European Molecular Biology Laboratory (EMBL), 71 Avenue des Martyrs, Grenoble 38042, France
| | - Rob Meijers
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, c/o Notkestrasse 85, Hamburg 22607, Germany
| | - Dmitri Svergun
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, c/o Notkestrasse 85, Hamburg 22607, Germany
| | - Christian Betzel
- Laboratory for Structural Biology of Infection and Inflammation, University Hamburg, c/o DESY, Building 22a, Notkestrasse 85, Hamburg 22603, Germany
| |
Collapse
|
14
|
Silva BFB. SAXS on a chip: from dynamics of phase transitions to alignment phenomena at interfaces studied with microfluidic devices. Phys Chem Chem Phys 2018; 19:23690-23703. [PMID: 28828415 DOI: 10.1039/c7cp02736b] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The field of microfluidics offers attractive possibilities to perform novel experiments that are difficult (or even impossible) to perform using conventional bulk and surface-based methods. Such attractiveness comes from several important aspects inherent to these miniaturized devices. First, the flow of fluids under submillimeter confinement typically leads to a drop of inertial forces, meaning that turbulence is practically suppressed. This leads to predictable and controllable flow profiles, along with well-defined chemical gradients and stress fields that can be used for controlled mixing and actuation on the micro and nanoscale. Secondly, intricate microfluidic device designs can be fabricated using cleanroom standard procedures. Such intricate geometries can take diverse forms, designed by researchers to perform complex tasks, that require exquisite control of flow of several components and gradients, or to mimic real world examples, facilitating the establishment of more realistic models. Thirdly, microfluidic devices are usually compatible with in situ or integrated characterization methods that allow constant real-time monitoring of the processes occurring inside the microchannels. This is very different from typical bulk-based methods, where usually one can only observe the final result, or otherwise, take quick snapshots of the evolving process or take aliquots to be analyzed separately. Altogether, these characteristics inherent to microfluidic devices provide researchers with a set of tools that allow not only exquisite control and manipulation of materials at the micro and nanoscale, but also observation of these effects. In this review, we will focus on the use and prospects of combining microfluidic devices with in situ small-angle X-ray scattering (and related techniques such as small-angle neutron scattering and X-ray photon correlation spectroscopy), and their enormous potential for physical-chemical research, mainly in self-assembly and phase-transitions, and surface characterization.
Collapse
Affiliation(s)
- Bruno F B Silva
- Department of Life Sciences, INL - International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga, Braga 4715-330, Portugal.
| |
Collapse
|
15
|
Yildiz-Ozturk E, Yucel M, Muderrisoglu C, Sargin S, Yesil-Celiktas O. Modelling coupled dynamics of diffusive–convective mass transfer in a microfluidic device and determination of hydrodynamic dispersion coefficient. J Taiwan Inst Chem Eng 2017. [DOI: 10.1016/j.jtice.2017.08.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
16
|
Bossert D, Natterodt J, Urban DA, Weder C, Petri-Fink A, Balog S. Speckle-Visibility Spectroscopy of Depolarized Dynamic Light Scattering. J Phys Chem B 2017. [DOI: 10.1021/acs.jpcb.7b04971] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- David Bossert
- Adolphe
Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
| | - Jens Natterodt
- Adolphe
Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
| | - Dominic A. Urban
- Adolphe
Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
| | - Christoph Weder
- Adolphe
Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
| | - Alke Petri-Fink
- Adolphe
Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
- Chemistry
Department, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland
| | - Sandor Balog
- Adolphe
Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
| |
Collapse
|
17
|
Adamo M, Poulos AS, Miller RM, Lopez CG, Martel A, Porcar L, Cabral JT. Rapid contrast matching by microfluidic SANS. LAB ON A CHIP 2017; 17:1559-1569. [PMID: 28379253 DOI: 10.1039/c7lc00179g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report a microfluidic approach to perform small angle neutron scattering (SANS) measurements of contrast variation and matching, extensively employed in soft and biological matter research. We integrate a low scattering background microfluidic mixer and serpentine channel in a SANS beamline to yield a single phase, continuous flow, reconfigurable liquid cell. By contrast with conventional, sequential measurements of discrete (typically 4-6) solutions of varying isotopic solvent composition, our approach continually varies solution composition during SANS acquisition. We experimentally and computationally determine the effects of flow dispersion and neutron beam overillumination of microchannels in terms of the composition resolution and precision. The approach is demonstrated with model systems: H2O/D2O mixtures, a surfactant (sodium dodecyl sulfate, SDS), a triblock copolymer (pluronic F127), and silica nanoparticles (Ludox) in isotopic aqueous mixtures. The system is able to zoom into a composition window to refine contrast matching conditions, and robustly resolve solute structure and form factors by simultaneous fitting of scattering data with continuously varying contrast. We conclude by benchmarking our microflow-SANS with the discrete approach, in terms of volume required, composition resolution and (preparation and measurement) time required, proposing a leap forward in equilibrium, liquid solution phase mapping and contrast variation by SANS.
Collapse
Affiliation(s)
- Marco Adamo
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
| | | | | | | | | | | | | |
Collapse
|
18
|
Liu X, Haddou M, Grillo I, Mana Z, Chapel JP, Schatz C. Early stage kinetics of polyelectrolyte complex coacervation monitored through stopped-flow light scattering. SOFT MATTER 2016; 12:9030-9038. [PMID: 27748777 DOI: 10.1039/c6sm01979j] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Polyelectrolyte complexes (PECs) between poly(acrylic acid) (PAA) and poly(diallyldimethylammonium chloride) (PDADMAC), a model system forming coacervate particles via electrostatic interaction at pH 10, were prepared by a stopped-flow (SF) fast mixing technique at different mixing charge ratios (z) and ionic strengths. Both PEC final morphologies prepared by either SF or manual one-shot mixing are similar at bench time. In situ light scattering combined with the SF technique pointed-out, however, the presence of three distinct early stage kinetic behaviors in the formation of PECs. The first stage observed at low z is ascribed to the relaxation/reorganization of soluble PECs. At higher z or in the presence of salt, a second stage is found corresponding to the aggregation and/or rearrangement of small soluble PECs into larger structures. Redistribution of excess charges among those PECs produces some neutral condensed coacervate droplets as well, coexisting with PECs in a wide range of mixing ratios. Finally, a last process featured with bell-shaped curves indicates the full coacervation that quickens while approaching charge neutrality and/or at higher ionic strength.
Collapse
Affiliation(s)
- Xiaoqing Liu
- CNRS, Centre de Recherche Paul Pascal (CRPP), UPR 8641, F-33600 Pessac, France. and Université de Bordeaux, Centre de Recherche Paul Pascal, F-33600 Pessac, France and Université de Bordeaux, Laboratoire de Chimie des Polymères Organiques, UMR 5629, IPB/ENSCBP, 16 avenue Pey-Berland, F-33607 Pessac, France and CNRS, Laboratoire de Chimie des Polymères Organiques, UMR 5629, F-33607 Pessac, France
| | - Marie Haddou
- CNRS, Centre de Recherche Paul Pascal (CRPP), UPR 8641, F-33600 Pessac, France. and Université de Bordeaux, Centre de Recherche Paul Pascal, F-33600 Pessac, France and Université de Bordeaux, Laboratoire de Chimie des Polymères Organiques, UMR 5629, IPB/ENSCBP, 16 avenue Pey-Berland, F-33607 Pessac, France and CNRS, Laboratoire de Chimie des Polymères Organiques, UMR 5629, F-33607 Pessac, France
| | - Isabelle Grillo
- Institut Laue Langevin, 71 avenue des martyrs, B.P. 156, 38042 Grenoble Cedex 9, France
| | - Zohra Mana
- Bio-logic SAS, 4 rue Vaucanson, 38170 Seyssinet Pariset, France
| | - Jean-Paul Chapel
- CNRS, Centre de Recherche Paul Pascal (CRPP), UPR 8641, F-33600 Pessac, France. and Université de Bordeaux, Centre de Recherche Paul Pascal, F-33600 Pessac, France
| | - Christophe Schatz
- Université de Bordeaux, Laboratoire de Chimie des Polymères Organiques, UMR 5629, IPB/ENSCBP, 16 avenue Pey-Berland, F-33607 Pessac, France and CNRS, Laboratoire de Chimie des Polymères Organiques, UMR 5629, F-33607 Pessac, France
| |
Collapse
|
19
|
Abdellatif AAH, Tawfeek HM. Transfersomal Nanoparticles for Enhanced Transdermal Delivery of Clindamycin. AAPS PharmSciTech 2016; 17:1067-74. [PMID: 26511937 DOI: 10.1208/s12249-015-0441-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 10/15/2015] [Indexed: 11/30/2022] Open
Abstract
The aim of this work was to study the potential of delivering clindamycin phosphate, as an efficient antibiotic drug, into a more absorbed, elastic ultradeformable form, transfersomes (TRSs). These vesicles showed an enhanced penetration through ex vivo permeation characters. TRSs were prepared using thin-film hydration method. Furthermore, they were evaluated for their entrapment efficiency, size, zeta potential, and morphology. Also, the prepared TRSs were converted into suitable gel formulation using carbopol 934 and were evaluated for their gel characteristics like pH, viscosity, spreadability, homogeneity, skin irritation, in vitro release, stability, and ex vivo permeation studies in rats. TRSs were efficiently formulated in a stable bilayer vesicle structure. Furthermore, clindamycin phosphate showed higher entrapment efficiency within the TRSs reaching about 93.3% ± 0.8 and has a uniform particle size. Moreover, the TRSs surface had a high negative charge which indicated the stability of the produced vesicles and resistance of aggregation. Clindamycin phosphate showed a significantly higher in vitro release (p < 0.05; ANOVA/Tukey) compared with the control carbopol gel. Furthermore, the transfersomal gel showed a significantly higher (p < 0.05; ANOVA/Tukey) cumulative amount of drug permeation and flux than both the transfersomal suspension and the control carbopol gel. In conclusion, the produced results suggest that TRS-loaded clindamycin are promising carriers for enhanced dermal delivery of clindamycin phosphate.
Collapse
|
20
|
Sekar S, Giermanska J, Saadaoui H, Chapel JP. Fine-tuning the assembly of highly stable oppositely charged cerium oxide nanoparticles in solution and at interfaces. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
21
|
Perro A, Lebourdon G, Henry S, Lecomte S, Servant L, Marre S. Combining microfluidics and FT-IR spectroscopy: towards spatially resolved information on chemical processes. REACT CHEM ENG 2016. [DOI: 10.1039/c6re00127k] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This review outlines the combination of infrared spectroscopy and continuous microfluidic processes.
Collapse
Affiliation(s)
- Adeline Perro
- Institut des Sciences Moléculaires
- Université de Bordeaux—CNRS
- 33405 Talence
- France
| | - Gwenaelle Lebourdon
- Institut des Sciences Moléculaires
- Université de Bordeaux—CNRS
- 33405 Talence
- France
| | - Sarah Henry
- Chimie et Biologie des Membranes et des Nanoobjets
- Université de Bordeaux —CNRS
- 33607 Pessac
- France
| | - Sophie Lecomte
- Chimie et Biologie des Membranes et des Nanoobjets
- Université de Bordeaux —CNRS
- 33607 Pessac
- France
| | - Laurent Servant
- Institut des Sciences Moléculaires
- Université de Bordeaux—CNRS
- 33405 Talence
- France
| | | |
Collapse
|
22
|
Beuvier T, Panduro EAC, Kwaśniewski P, Marre S, Lecoutre C, Garrabos Y, Aymonier C, Calvignac B, Gibaud A. Implementation of in situ SAXS/WAXS characterization into silicon/glass microreactors. LAB ON A CHIP 2015; 15:2002-2008. [PMID: 25792250 DOI: 10.1039/c5lc00115c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A successful implementation of in situ X-ray scattering analysis of synthetized particle materials in silicon/glass microreactors is reported. Calcium carbonate (CaCO3) as a model material was precipitated inside the microchannels through the counter-injection of two aqueous solutions, containing carbonate ions and calcium ions, respectively. The synthesized calcite particles were analyzed in situ in aqueous media by combining Small Angle X-ray Scattering (SAXS) and Wide Angle X-ray Scattering (WAXS) techniques at the ESRF ID02 beam line. At high wavevector transfer, WAXS patterns clearly exhibit different scattering features: broad scattering signals originating from the solvent and the glass lid of the chip, and narrow diffraction peaks coming from CaCO3 particles precipitated rapidly inside the microchannel. At low wavevector transfer, SAXS reveals the rhombohedral morphology of the calcite particles together with their micrometer size without any strong background, neither from the chip nor from the water. This study demonstrates that silicon/glass chips are potentially powerful tools for in situ SAXS/WAXS analysis and are promising for studying the structure and morphology of materials in non-conventional conditions like geological materials under high pressure and high temperature.
Collapse
Affiliation(s)
- Thomas Beuvier
- LUNAM, Université du Maine, Institut des Molécules et Matériaux du Mans, UMR CNRS 6283, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9, France.
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Kornreich M, Heymann M, Fraden S, Beck R. Cross polarization compatible dialysis chip. LAB ON A CHIP 2014; 14:3700-3704. [PMID: 25105977 DOI: 10.1039/c4lc00600c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We visualize birefringence in microliter sample volumes using a microfluidic dialysis chip optimized for cross polarization microscopy. The chip is composed of two overlapping polydimethylsiloxane (PDMS) channels separated by a commercial cellulose ester membrane. Buffer exchange in the sample chamber is achieved within minutes by dialyzing under continuous reservoir flow. Using fd virus as a birefringent model system, we monitor the fd virus isotropic to liquid crystal phase transition as a function of ionic strength. We show that the reorientation of the fd virus spans a few tens of seconds, indicative of fast ion exchange across the membrane. Complete phase separation reorganization takes minutes to hours as it involves diffusive virus mass transport within the storage chamber.
Collapse
Affiliation(s)
- Micha Kornreich
- The Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, 69978 Tel Aviv, Israel.
| | | | | | | |
Collapse
|
24
|
Chomean S, Wangmaung N, Sritongkham P, Promptmas C, Mas-oodi S, Tanyong D, Ittarat W. Molecular diagnosis of α-thalassemias by the colorimetric nanogold. Analyst 2014; 139:813-22. [DOI: 10.1039/c3an01606d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
25
|
Sans V, Glatzel S, Douglas FJ, Maclaren DA, Lapkin A, Cronin L. Non-equilibrium dynamic control of gold nanoparticle and hyper-branched nanogold assemblies. Chem Sci 2014. [DOI: 10.1039/c3sc53223b] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
26
|
Teste B, Ali-Cherif A, Viovy JL, Malaquin L. A low cost and high throughput magnetic bead-based immuno-agglutination assay in confined droplets. LAB ON A CHIP 2013; 13:2344-9. [PMID: 23640128 DOI: 10.1039/c3lc50353d] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Although passive immuno-agglutination assays consist of one step and simple procedures, they are usually not adapted for high throughput analyses and they require expensive and bulky equipment for quantitation steps. Here we demonstrate a low cost, multimodal and high throughput immuno-agglutination assay that relies on a combination of magnetic beads (MBs), droplets microfluidics and magnetic tweezers. Antibody coated MBs were used as a capture support in the homogeneous phase. Following the immune interaction, water in oil droplets containing MBs and analytes were generated and transported in Teflon tubing. When passing in between magnetic tweezers, the MBs contained in the droplets were magnetically confined in order to enhance the agglutination rate and kinetics. When releasing the magnetic field, the internal recirculation flows in the droplet induce shear forces that favor MBs redispersion. In the presence of the analyte, the system preserves specific interactions and MBs stay in the aggregated state while in the case of a non-specific analyte, redispersion of particles occurs. The analyte quantitation procedure relies on the MBs redispersion rate within the droplet. The influence of different parameters such as magnetic field intensity, flow rate and MBs concentration on the agglutination performances have been investigated and optimized. Although the immuno-agglutination assay described in this work may not compete with enzyme linked immunosorbent assay (ELISA) in terms of sensitivity, it offers major advantages regarding the reagents consumption (analysis is performed in sub microliter droplet) and the platform cost that yields to very cheap analyses. Moreover the fully automated analysis procedure provides reproducible analyses with throughput well above those of existing technologies. We demonstrated the detection of biotinylated phosphatase alkaline in 100 nL sample volumes with an analysis rate of 300 assays per hour and a limit of detection of 100 pM.
Collapse
Affiliation(s)
- Bruno Teste
- Institut Curie, Centre de Recherche, Paris, France
| | | | | | | |
Collapse
|
27
|
Braun J, Renggli K, Razumovitch J, Vebert C. Dynamic Light Scattering in Supramolecular Materials Chemistry. Supramol Chem 2012. [DOI: 10.1002/9780470661345.smc039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
28
|
Berret JF. Controlling electrostatic co-assembly using ion-containing copolymers: from surfactants to nanoparticles. Adv Colloid Interface Sci 2011; 167:38-48. [PMID: 21376298 DOI: 10.1016/j.cis.2011.01.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 01/27/2011] [Accepted: 01/27/2011] [Indexed: 10/18/2022]
Abstract
In this review, we address the issue of the electrostatic complexation between charged-neutral diblock copolymers and oppositely charged nanocolloids. We show that nanocolloids such as surfactant micelles and iron oxide magnetic nanoparticles share similar properties when mixed with charged-neutral diblocks. Above a critical charge ratio, core-shell hierarchical structures form spontaneously under direct mixing conditions. The core-shell structures are identified by a combination of small-angle scattering techniques and transmission electron microscopy. The formation of multi-level objects is driven by the electrostatic attraction between opposite charges and by the release of the condensed counterions. Alternative mixing processes inspired from molecular biology are also described. The protocols applied here consist in screening the electrostatic interactions of the mixed dispersions, and then removing the salt progressively as an example by dialysis. With these techniques, the oppositely charged species are intimately mixed before they can interact, and their association is monitored by the desalting kinetics. As a result, sphere- and wire-like aggregates with remarkable superparamagnetic and stability properties are obtained. These findings are discussed in the light of a new paradigm which deals with the possibility to use inorganic nanoparticles as building blocks for the design and fabrication of supracolloidal assemblies with enhanced functionalities.
Collapse
|