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Gao Z, Yan F, Shi L, Han Y, Qiu S, Zhang J, Wang F, Wu S, Tian W. Acylhydrazone-based supramolecular assemblies undergoing a converse sol-to-gel transition on trans → cis photoisomerization. Chem Sci 2022; 13:7892-7899. [PMID: 35865886 PMCID: PMC9258502 DOI: 10.1039/d2sc01657e] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 06/14/2022] [Indexed: 11/21/2022] Open
Abstract
Photoisomeric supramolecular assemblies have drawn enormous attention in recent years. Although it is a general rule that photoisomerization from a less to a more distorted isomer causes the destruction of assemblies, this photoisomerization process inducing a converse transition from irregular aggregates to regular assemblies is still a great challenge. Here, we report a converse sol-to-gel transition derived from the planar to nonplanar photoisomer conversion, which is in sharp contrast to the conventional light-induced gel collapse. A well-designed acylhydrazone-linked monomer is exploited as a photoisomer to realize the above-mentioned phase transition. In the monomer, imine is responsible for trans–cis interconversion and amide generates intermolecular hydrogen bonds enabling the photoisomerization-driven self-assembly. The counterintuitive feature of the sol-to-gel transition is ascribed to the partial trans → cis photoisomerization of acylhydrazone causing changes in stacking mode of monomers. Furthermore, the reversible phase transition is applied in the valves formed in situ in microfluidic devices, providing fascinating potential for miniature materials. A converse sol-to-gel transition system based on trans → cis photoisomerization of acylhydrazone-based supramolecular assemblies has been sucessfully established, which was applied in the gel-based microvalves that can in situ control flow by light.![]()
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Affiliation(s)
- Zhao Gao
- Shaanxi Key Laboratory of Macromolecular Science and Technology, MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University Xi'an 710072 P. R. China
| | - Fei Yan
- Shaanxi Key Laboratory of Macromolecular Science and Technology, MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University Xi'an 710072 P. R. China
| | - Lulu Shi
- Shaanxi Key Laboratory of Macromolecular Science and Technology, MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University Xi'an 710072 P. R. China
| | - Yifei Han
- Department of Polymer Science and Engineering, University of Science and Technology of China Hefei Anhui 230026 P. R. China
| | - Shuai Qiu
- Shaanxi Key Laboratory of Macromolecular Science and Technology, MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University Xi'an 710072 P. R. China
| | - Juan Zhang
- Shaanxi Key Laboratory of Macromolecular Science and Technology, MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University Xi'an 710072 P. R. China
| | - Feng Wang
- Department of Polymer Science and Engineering, University of Science and Technology of China Hefei Anhui 230026 P. R. China
| | - Si Wu
- Department of Polymer Science and Engineering, University of Science and Technology of China Hefei Anhui 230026 P. R. China
| | - Wei Tian
- Shaanxi Key Laboratory of Macromolecular Science and Technology, MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University Xi'an 710072 P. R. China
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2
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Rebello NJ, Beech HK, Olsen BD. Adding the Effect of Topological Defects to the Flory-Rehner and Bray-Merrill Swelling Theories. ACS Macro Lett 2021; 10:531-537. [PMID: 35570765 DOI: 10.1021/acsmacrolett.0c00909] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The Flory-Rehner and Bray-Merrill swelling theories are venerable theories for calculating the swelling of polymer networks and are widely applied across polymer materials. Here, these theories are revised to include cyclic topological defects present in polymer networks by using a modified phantom network model. These closed-form equations assume defect contributions to the swelling elasticity to be linear and additive and allow different assumptions regarding prestrain of larger loops to be incorporated. To compare to the theories, swelling experiments are performed on end-linked poly(ethylene glycol) gels in which the topological defects (primary and secondary loops) have been previously measured. Gels with higher loop densities exhibit higher swelling ratios. An equation is derived to compare swelling models independent of knowledge of the Flory-Huggins χ parameter, showing that the revised swelling models for loop defects are more accurate than both the phantom network model that neglects loops and the Bray-Merrill equation.
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Affiliation(s)
- Nathan J. Rebello
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Haley K. Beech
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Bradley D. Olsen
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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Xiong Y, Kuksenok O. Mechanical Adaptability of Patterns in Constrained Hydrogel Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:4900-4912. [PMID: 33844552 DOI: 10.1021/acs.langmuir.1c00138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Pattern formation and dynamic restructuring play a vital role in a plethora of natural processes. Understanding and controlling pattern formation in soft synthetic materials is important for imparting a range of biomimetic functionalities. Using a three-dimensional gel Lattice spring model, we focus on the dynamics of pattern formation and restructuring in thin thermoresponsive poly(N-isopropylacrylamide) membranes under mechanical forcing via stretching and compression. A mechanical instability due to the constrained swelling of a polymer network in response to the temperature quench results in out-of-plane buckling of these membranes. The depth of the temperature quench and applied mechanical forcing affect the onset of buckling and postbuckling dynamics. We characterize formation and restructuring of buckling patterns under the stretching and compression by calculating the wavelength and the amplitude of these patterns. We demonstrate dynamic restructuring of the patterns under mechanical forcing and characterize the hysteresis behavior. Our findings show that in the range of the strain rates probed, the wavelength prescribed during the compression remains constant and independent of the sample widths, while the amplitude is regulated dynamically. We demonstrate that significantly smaller wavelengths can be prescribed and sustained dynamically than those achieved in equilibrium in the same systems. We show that an effective membrane thickness may decrease upon compression due to the out-of-plane deformations and pattern restructuring. Our findings point out that mechanical forcing can be harnessed to control the onset of buckling, postbuckling dynamics, and hysteresis phenomena in gel-based systems, introducing novel means of tailoring the functionality of soft structured surfaces and interfaces.
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Affiliation(s)
- Yao Xiong
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Olga Kuksenok
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
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4
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Che Y, Zschoche S, Obst F, Appelhans D, Voit B. Double‐crosslinked reversible redox‐responsive hydrogels based on disulfide–thiol interchange. ACTA ACUST UNITED AC 2019. [DOI: 10.1002/pola.29539] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Yunjiao Che
- Leibniz‐Institute für Polymerforschung Dresden e.V. Hohe Straße 6, 01069 Dresden Germany
- Organic Chemistry of Polymers Technische Universität Dresden, Faculty of Science 01062 Dresden Germany
| | - Stefan Zschoche
- Leibniz‐Institute für Polymerforschung Dresden e.V. Hohe Straße 6, 01069 Dresden Germany
| | - Franziska Obst
- Leibniz‐Institute für Polymerforschung Dresden e.V. Hohe Straße 6, 01069 Dresden Germany
- Organic Chemistry of Polymers Technische Universität Dresden, Faculty of Science 01062 Dresden Germany
| | - Dietmar Appelhans
- Leibniz‐Institute für Polymerforschung Dresden e.V. Hohe Straße 6, 01069 Dresden Germany
| | - Brigitte Voit
- Leibniz‐Institute für Polymerforschung Dresden e.V. Hohe Straße 6, 01069 Dresden Germany
- Organic Chemistry of Polymers Technische Universität Dresden, Faculty of Science 01062 Dresden Germany
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5
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Hines L, Petersen K, Lum GZ, Sitti M. Soft Actuators for Small-Scale Robotics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1603483. [PMID: 28032926 DOI: 10.1002/adma.201603483] [Citation(s) in RCA: 492] [Impact Index Per Article: 70.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 10/05/2016] [Indexed: 05/17/2023]
Abstract
This review comprises a detailed survey of ongoing methodologies for soft actuators, highlighting approaches suitable for nanometer- to centimeter-scale robotic applications. Soft robots present a special design challenge in that their actuation and sensing mechanisms are often highly integrated with the robot body and overall functionality. When less than a centimeter, they belong to an even more special subcategory of robots or devices, in that they often lack on-board power, sensing, computation, and control. Soft, active materials are particularly well suited for this task, with a wide range of stimulants and a number of impressive examples, demonstrating large deformations, high motion complexities, and varied multifunctionality. Recent research includes both the development of new materials and composites, as well as novel implementations leveraging the unique properties of soft materials.
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Affiliation(s)
- Lindsey Hines
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569, Stuttgart, Germany
| | | | - Guo Zhan Lum
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569, Stuttgart, Germany
| | - Metin Sitti
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569, Stuttgart, Germany
- Max Planck ETH Center for Learning Systems, Heisenbergstraße 3, 70569, Stuttgart, Germany
- Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, PA, 15213, USA
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6
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Jing M, Fu Y, Fei X, Tian J, Zhi H, Zhang H, Xu L, Wang X, Wang Y. A novel high-strength polymer hydrogel with identifiability prepared via a one-pot method. Polym Chem 2017. [DOI: 10.1039/c7py00563f] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A simple one-pot method was developed to fabricate a novel hydrogel with good biocompatibility, excellent mechanical properties, and identifiability via photopolymerization and sol–gel processes.
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Affiliation(s)
- Muzi Jing
- Instrumental Analysis Center
- Dalian Polytechnic University
- Dalian 116034
- P. R. China
- School of Biological Engineering
| | - Yang Fu
- Harbin stomatological hospital
- Harbin 150000
- P. R. China
| | - Xu Fei
- Instrumental Analysis Center
- Dalian Polytechnic University
- Dalian 116034
- P. R. China
| | - Jing Tian
- School of Biological Engineering
- Dalian Polytechnic University
- Dalian 116034
- P. R. China
| | - Hui Zhi
- Instrumental Analysis Center
- Dalian Polytechnic University
- Dalian 116034
- P. R. China
- School of Biological Engineering
| | - Haiyang Zhang
- School of Biological Engineering
- Dalian Polytechnic University
- Dalian 116034
- P. R. China
| | - Longquan Xu
- Instrumental Analysis Center
- Dalian Polytechnic University
- Dalian 116034
- P. R. China
| | - Xiuying Wang
- Instrumental Analysis Center
- Dalian Polytechnic University
- Dalian 116034
- P. R. China
| | - Yi Wang
- School of Biological Engineering
- Dalian Polytechnic University
- Dalian 116034
- P. R. China
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8
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Abstract
Molecular diffusive membranes or materials are important for biological applications in microfluidic systems. Hydrogels are typical materials that offer several advantages, such as free diffusion for small molecules, biocompatibility with most cells, temperature sensitivity, relatively low cost, and ease of production. With the development of microfluidic applications, hydrogels can be integrated into microfluidic systems by soft lithography, flow-solid processes or UV cure methods. Due to their special properties, hydrogels are widely used as fluid control modules, biochemical reaction modules or biological application modules in different applications. Although hydrogels have been used in microfluidic systems for more than ten years, many hydrogels' properties and integrated techniques have not been carefully elaborated. Here, we systematically review the physical properties of hydrogels, general methods for gel-microfluidics integration and applications of this field. Advanced topics and the outlook of hydrogel fabrication and applications are also discussed. We hope this review can help researchers choose suitable methods for their applications using hydrogels.
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Affiliation(s)
- Xuanqi Zhang
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
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9
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Poly(N-isopropylacrylamide)-based ionic hydrogels: synthesis, swelling properties, interfacial adsorption and release of dyes. Polym J 2016. [DOI: 10.1038/pj.2015.123] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Li H, Hao D, Fan J, Song S, Guo X, Song W, Liu M, Jiang L. A robust double-network hydrogel with under sea water superoleophobicity fabricated via one-pot, one-step reaction. J Mater Chem B 2016; 4:4662-4666. [DOI: 10.1039/c6tb00818f] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A robust double-network (DN) hydrogel fabricated by a one-pot, one-step reaction is reported.
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Affiliation(s)
- Hao Li
- Beijing National Laboratory for Molecular Sciences (BNLMS)
- Key Laboratory of Green Printing
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing
| | - Dezhao Hao
- Beijing National Laboratory for Molecular Sciences (BNLMS)
- Key Laboratory of Green Printing
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing
| | - Junbing Fan
- Technical Institute of Physics and Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Sufen Song
- Beijing National Laboratory for Molecular Sciences (BNLMS)
- Key Laboratory of Green Printing
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing
| | - Xinglin Guo
- Beijing National Laboratory for Molecular Sciences (BNLMS)
- Key Laboratory of Green Printing
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing
| | - Wenlong Song
- The State Key Laboratory of Supramolecular Structure and Materials, Jilin University
- Changchun 130023
- P. R. China
| | - Mingjie Liu
- The State Key Laboratory of Supramolecular Structure and Materials, Jilin University
- Changchun 130023
- P. R. China
| | - Lei Jiang
- Beijing National Laboratory for Molecular Sciences (BNLMS)
- Key Laboratory of Green Printing
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing
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11
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Raia L, Rondelli N, Bianchessi M, Carminati M. Microfluidic structures for large-scale manufacture combining photo-patternable materials. RSC Adv 2016. [DOI: 10.1039/c6ra11962j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Novel use of SiNR, a robust wafer bonding dry adhesive, for industrial and automatable fabrication of microfluidics compatible with DNA analysis.
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Affiliation(s)
- L. Raia
- STMicroelectronics
- Advanced Systems Technology (AST)
- 20041 Agrate Brianza (MI)
- Italy
| | - N. Rondelli
- STMicroelectronics
- Advanced Systems Technology (AST)
- 20041 Agrate Brianza (MI)
- Italy
| | - M. Bianchessi
- STMicroelectronics
- Advanced Systems Technology (AST)
- 20041 Agrate Brianza (MI)
- Italy
| | - M. Carminati
- Politecnico di Milano
- Dipartimento di Elettronica
- Informazione e Bioingegneria (DEIB)
- 20133 Milano
- Italy
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12
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Costa AM, Mano JF. Extremely strong and tough hydrogels as prospective candidates for tissue repair – A review. Eur Polym J 2015. [DOI: 10.1016/j.eurpolymj.2015.07.053] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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13
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Silva JE, Geryak R, Loney DA, Kottke PA, Naik RR, Tsukruk VV, Fedorov AG. Stick-slip water penetration into capillaries coated with swelling hydrogel. SOFT MATTER 2015; 11:5933-5939. [PMID: 26119374 DOI: 10.1039/c5sm00660k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have observed intriguing stick-slip behavior during capillary pressure driven filling of borosilicate microtubes coated with hydrogel on their inner wall. Swelling of hydrogel upon exposure to a translating waterfront is accompanied by "stick-and-slip" motion. This results in the macroscopic filling velocity for water penetration into glass capillaries coated with poly(N-isopropylacrylamide) (PNIPAM) being constant throughout the filling process, and reduced by three orders of magnitude when compared to filling of uncoated capillaries. A simple scaling analysis is used to introduce a possible explanation by considering the mechanisms responsible for pinning and unpinning of the contact line. The explanation assumes that the time scale for water diffusion into a hydrogel film and the resulting swelling/change of the local meniscus contact angle define the duration of each "stick" event. The "slip" length scale is in turn established by the elastocapillary deformation of dry hydrogel at the pinning point of the contact line. The sequential dynamics of these processes then determine the rate of water filling into a swelling capillary. Collectively, these experimental and theoretical results provide a new conceptual framework for liquid motion confined by soft, dynamically evolving polymer interfaces, in which the system creates an energy barrier to further motion through elasto-capillary deformation, and then lowers the barrier through diffusive softening. This insight has implications for optimal design of microfluidic and lab-on-a-chip devices based on stimuli-responsive smart polymers.
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Affiliation(s)
- J E Silva
- Department of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
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14
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Jin S, Park TM, Kim CH, Kim JS, Le BD, Jeong YH, Kwak JY, Yoon S. Three-dimensional migration of neutrophils through an electrospun nanofibrous membrane. Biotechniques 2015; 58:285-92. [PMID: 26054764 DOI: 10.2144/000114297] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 03/12/2015] [Indexed: 11/23/2022] Open
Abstract
The study of immune cell migration is important for understanding the immune system network, which is associated with the response to foreign cells. Neutrophils act against foreign cells before any other immune cell, and they must be able to change shape and squeeze through narrow spaces in the extracellular matrix (ECM) during migration to sites of infection. Conventional in vitro migration assays are typically performed on two-dimensional substrates that fail to reproduce the three-dimensional (3-D) nature of the ECM. Here we present an in vitro method to simulate the 3-D migration of neutrophils using an electrospun nanofibrous membrane, which is similar to the ECM in terms of morphology. We examined the properties of neutrophil movement and the effects of gravity and the presence of IL-8, which has been widely used as a chemotactic attractant for neutrophils. The number of neutrophils passing through the nanofibrous membrane were higher, and their movement was more active in the presence of IL-8. Also, we confirmed that neutrophils could migrate against gravity toward IL-8 through a nanofibrous membrane.
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Affiliation(s)
- Songwan Jin
- Department of Mechanical Engineering, Korea Polytechnic University, Siheung, Gyeonggy-do, South Korea
| | - Tae-Min Park
- Department of Advanced Convergence Technology, Korea Polytechnic University, Siheung, Gyeonggy-do, South Korea
| | - Cho-Hee Kim
- Department of Biochemistry, Dong-A University, Busan, South Korea
| | - Jin-Soo Kim
- Department of Mechanical Engineering, Korea Polytechnic University, Siheung, Gyeonggy-do, South Korea
| | - Binh Duong Le
- Department of Mechanical Engineering, Korea Polytechnic University, Siheung, Gyeonggy-do, South Korea
| | - Young Hun Jeong
- School of Mechanical Engineering, Kyungpook National University, Daegu, South Korea
| | - Jong-Young Kwak
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Gyeonggy-do, South Korea
| | - Sik Yoon
- Department of Anatomy, Pusan National University School of Medicine, Yangsan, Gyeongsangnam-do, South Korea
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15
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16
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Lin S, Wang W, Ju XJ, Xie R, Chu LY. A simple strategy for in situ fabrication of a smart hydrogel microvalve within microchannels for thermostatic control. LAB ON A CHIP 2014; 14:2626-2634. [PMID: 24810920 DOI: 10.1039/c4lc00039k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Self-regulation of temperature in microchip systems is crucial for their applications in biomedical fields such as cell culture and biomolecule synthesis as well as those cases that require constant temperature conditions. Here we report on a simple and versatile approach for in situ fabrication of a smart hydrogel microvalve within a microchip for thermostatic control. The thermo-responsive hydrogel microvalve enables the "on-off" switch by sensing temperature fluctuations to control the fluid flux as well as the fluid heat exchange for self-regulation of the temperature at a constant range. Such temperature self-regulation is demonstrated by integrating the microvalve-incorporated microchip into the flow circulation loop of a micro-heat-exchanging system for thermostatic control. Moreover, the microvalve-incorporated microchip is employed for culturing cells under temperature self-regulation. The smart microvalve shows great potential as a temperature controller for applications that require thermostatic conditions. This approach offers a facile and flexible strategy for in situ fabricating hydrogel microvalves within microchips as chemostats and microreactors for biomedical applications.
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Affiliation(s)
- Shuo Lin
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
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17
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Radiation-induced synthesis of thermo-sensitive, gradient hydrogels based on 2-(2-methoxyethoxy)ethyl methacrylate. Radiat Phys Chem Oxf Engl 1993 2014. [DOI: 10.1016/j.radphyschem.2014.03.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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18
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Park S, Kim D, Ko SY, Park JO, Akella S, Xu B, Zhang Y, Fraden S. Controlling uniformity of photopolymerized microscopic hydrogels. LAB ON A CHIP 2014; 14:1551-1563. [PMID: 24626640 DOI: 10.1039/c4lc00158c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This paper studies hydrogels created by photopolymerization with a uniform beam of light. Under some conditions the density profiles of the resulting hydrogels were uniform cylinders, mirroring the illumination profiles. However, under other conditions, gels with hollow cylindrical shapes were formed. We studied the photopolymerization of poly-N-isopropylacrylamide (pNIPAAM), a hydrogel that has been widely used in tissue engineering and microfluidic applications, and examined how the size and uniformity of pNIPAAM microscopic gels can be controlled by varying parameters such as exposure time, exposure area, exposure intensity, monomer concentration, photoinitiator concentration and terminator concentration. A simplified reaction-diffusion model of the polymerization process was developed and was found to describe the experiment for a wide range of parameters. This general framework will guide attempts to establish optimal conditions for the construction of microscopic hydrogels using photolithography, which is a method that has found applications in fields such as microfluidics, drug delivery, cell and tissue culturing, and high resolution 3D printing.
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Affiliation(s)
- Sukho Park
- School of Mechanical Engineering, Chonnam National University, South Korea
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19
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Chen Q, Zhu L, Zhao C, Wang Q, Zheng J. A robust, one-pot synthesis of highly mechanical and recoverable double network hydrogels using thermoreversible sol-gel polysaccharide. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:4171-6. [PMID: 23765594 DOI: 10.1002/adma.201300817] [Citation(s) in RCA: 427] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 04/27/2013] [Indexed: 05/22/2023]
Abstract
A new type of physically linked double-network hydrogel is synthesized by a simple, time-saving, facile, easily controlled, one-pot method. The resulting agar/polyacrylamide double-network hydrogels exhibit good mechanical properties, excellent recoverability, and a unique free-shapeable property, which makes them very promising hydrogels for load-bearing soft tissues.
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Affiliation(s)
- Qiang Chen
- School of Material Science and Engineering, Henan Polytechnic University, Jiaozuo, China
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20
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Hitzbleck M, Delamarche E. Reagents in microfluidics: an 'in' and 'out' challenge. Chem Soc Rev 2013; 42:8494-516. [PMID: 23925517 DOI: 10.1039/c3cs60118h] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Microfluidic devices are excellent at downscaling chemical and biochemical reactions and thereby can make reactions faster, better and more efficient. It is therefore understandable that we are seeing these devices being developed and used for many applications and research areas. However, microfluidic devices are more complex than test tubes or microtitre plates and the integration of reagents into them is a real challenge. This review looks at state-of-the-art methods and strategies for integrating various classes of reagents inside microfluidics and similarly surveys how reagents can be released inside microfluidics. The number of methods used for integrating and releasing reagents is surprisingly large and involves reagents in dry and liquid forms, directly-integrated reagents or reagents linked to carriers, as well as active, passive and hybrid release methods. We also made a brief excursion into the field of drug release and delivery. With this review, we hope to provide a large number of examples of integrating and releasing reagents that can be used by developers and users of microfluidics for their specific needs.
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Lu CH, Qi XJ, Orbach R, Yang HH, Mironi-Harpaz I, Seliktar D, Willner I. Switchable catalytic acrylamide hydrogels cross-linked by hemin/G-quadruplexes. NANO LETTERS 2013; 13:1298-1302. [PMID: 23421921 DOI: 10.1021/nl400078g] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Copolymer chains consisting of acrylamide units and guanine (G)-containing oligonucleotide-tethered acrylamide units undergo, in the presence of K(+) ions, cross-linking by G-quadruplexes to yield a hydrogel. The hydrogel is dissociated upon addition of 18-crown-6 ether that traps the K(+) ions. Reversible formation and dissociation of the hydrogel is demonstrated by the cyclic addition of K(+) ions and 18-crown-6 ether, respectively. Formation of the hydrogel in the presence of hemin results in a hemin/G-quadruplex-cross-linked catalytic hydrogel mimicking the function of horseradish peroxidase, reflected by the catalyzed oxidation of 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid), ABTS(2-), by H2O2 to ABTS(·-) and by the catalyzed generation of chemiluminescence in the presence of luminol/H2O2. Cyclic "ON" and "OFF" activation of the catalytic functions of the hydrogel are demonstrated upon the formation of the hydrogel in the presence of K(+) ions and its dissociation by 18-crown-6 ether, respectively. The hydrogel is characterized by rheology measurements, circular dichroism, and probing its chemical and photophysical properties.
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Affiliation(s)
- Chun-Hua Lu
- Institute of Chemistry, The Hebrew University of Jerusalem and The Center for Nanoscience and Nanotechnology, Jerusalem 91904, Israel
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22
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Saunders JR, Moussa W. Dynamic mechanical properties and swelling of UV-photopolymerized anionic hydrogels. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/polb.23114] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Gray KM, Liba BD, Wang Y, Cheng Y, Rubloff GW, Bentley WE, Montembault A, Royaud I, David L, Payne GF. Electrodeposition of a biopolymeric hydrogel: potential for one-step protein electroaddressing. Biomacromolecules 2012; 13:1181-9. [PMID: 22414205 DOI: 10.1021/bm3001155] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The electrodeposition of hydrogels provides a programmable means to assemble soft matter for various technological applications. We report an anodic method to deposit hydrogel films of the aminopolysaccharide chitosan. Evidence suggests the deposition mechanism involves the electrolysis of chloride to generate reactive chlorine species (e.g., HOCl) that partially oxidize chitosan to generate aldehydes that can couple covalently with amines (presumably through Schiff base linkages). Chitosan's anodic deposition is controllable spatially and temporally. Consistent with a covalent cross-linking mechanism, the deposited chitosan undergoes repeated swelling/deswelling in response to pH changes. Consistent with a covalent conjugation mechanism, proteins could be codeposited and retained within the chitosan film even after detergent washing. As a proof-of-concept, we electroaddressed glucose oxidase to a side-wall electrode of a microfabricated fluidic channel and demonstrated this enzyme could perform electrochemical biosensing functions. Thus, anodic chitosan deposition provides a reagentless, single-step method to electroaddress a stimuli-responsive and biofunctionalized hydrogel film.
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Affiliation(s)
- Kelsey M Gray
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, Maryland 20742, United States
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Yoon JA, Bencherif SA, Aksak B, Kim EK, Kowalewski T, Oh JK, Matyjaszewski K. Thermoresponsive hydrogel scaffolds with tailored hydrophilic pores. Chem Asian J 2011; 6:128-36. [PMID: 21162088 DOI: 10.1002/asia.201000514] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Thermoresponsive hydrogels with efficient water-release channels were prepared by incorporating star-shaped macromolecular pore precursors, with degradable disulfide crosslinked cores and hydrophilic poly(ethylene oxide) (PEO) arms, into the gel network. The gel framework exhibiting lower critical solution temperature (LCST) behavior was synthesized by atom transfer radical polymerization (ATRP) of 2-(2-methoxyethoxy)ethyl methacrylate and ethylene glycol dimethacrylate. The incorporation of degradable star macromolecules (dSM) was facilitated by growing the gel from ATRP initiator sites contained within their cores. Following the formation of the gel, the dSM cores were degraded, yielding uniform pores lined with hydrophilic PEO chains. The effect of hydrophilic pores on thermoresponsive hydrogel performances was studied by comparing hydrogels containing hydrophilic pores with analogous hydrogels with neutral pores or with pore-free controls. Dye absorption/release experiments pointed to the suitability of newly synthesized hydrogels as controlled-release media, for example, for drug delivery. Cell culture experiments confirmed their nontoxicity and biocompatibility (cell viability >98%).
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Affiliation(s)
- Jeong Ae Yoon
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
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25
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Tekin H, Anaya M, Brigham MD, Nauman C, Langer R, Khademhosseini A. Stimuli-responsive microwells for formation and retrieval of cell aggregates. LAB ON A CHIP 2010; 10:2411-8. [PMID: 20664846 PMCID: PMC3118411 DOI: 10.1039/c004732e] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Generating cell aggregates is beneficial for various applications ranging from biotechnology to regenerative therapies. Previously, poly(ethylene glycol) (PEG) microwells have been demonstrated as a potentially useful method for generating controlled-size cell aggregates. In addition to controlling cell aggregate size and homogeneity, the ability to confine cell aggregates on glass adhesive substrates and subsequently retrieve aggregates from microwells for further experimentation and analysis could be beneficial for various applications. However, it is often difficult to retrieve cell aggregates from these microwells without the use of digestive enzymes. This study describes the stable formation of cell aggregates in responsive microwells with adhesive substrates and their further retrieval in a temperature dependent manner by exploiting the stimuli responsiveness of these microwells. The responsive polymer structure of the arrays can be used to thermally regulate the microwell diameters causing a mechanical force on the aggregates, subsequently facilitating the retrieval of cell aggregates from the microwells with high efficiency compared to PEG arrays. This approach can be potentially integrated into high-throughput systems and may become a versatile tool for various applications that require aggregate formation and experimentation, such as tissue engineering, drug discovery, and stem cell biology.
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Affiliation(s)
- Halil Tekin
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
- Department of Medicine, Center for Biomedical Engineering, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Michael Anaya
- Department of Medicine, Center for Biomedical Engineering, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Mark D. Brigham
- Department of Medicine, Center for Biomedical Engineering, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Claire Nauman
- Department of Medicine, Center for Biomedical Engineering, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Robert Langer
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Ali Khademhosseini
- Department of Medicine, Center for Biomedical Engineering, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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Kini GC, Lai J, Wong MS, Biswal SL. Microfluidic formation of ionically cross-linked polyamine gels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:6650-6656. [PMID: 20078130 DOI: 10.1021/la903983y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In this article, we discuss in situ polymer gelation in microfluidic channels from electrostatically mediated interactions when reactant streams of a linear cationic polymer (poly(allylamine hydrochloride, PAH) and a multivalent anion (sodium citrate) are subjected to shear flow. We find that the polyamine exhibits shear-thickening behavior as it is ionically cross-linked by citrate ions to form viscoelastic gel phases. These gels form at room temperature and remain stable and intact after the cessation of flow. Gelation is found to occur in the polymer stream and not the citrate stream because of an appreciably higher diffusivity of citrate ions when compared to the gel and PAH and because of laminar flow conditions in the microfluidic environment. Gel formation occurred when the pH of the PAH stream was below the PAH pK(a) value of 8.38 and when citrate was either in a disodium or trisodium state. The formation of aggregates, gels, and droplets was found to depend strongly on the charge ratio and flow conditions. The gelation of PAH begins with the formation of colloidal aggregates of PAH and citrate, which then combine under shear flow to form noncontinuous or continuous gels. Droplets of citrate can form within regions of continuous gels as excess citrate anions diffuse into the gel stream.
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Affiliation(s)
- Gautam C Kini
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas, USA
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Yoon JA, Gayathri C, Gil RR, Kowalewski T, Matyjaszewski K. Comparison of the Thermoresponsive Deswelling Kinetics of Poly(2-(2-methoxyethoxy)ethyl methacrylate) Hydrogels Prepared by ATRP and FRP. Macromolecules 2010. [DOI: 10.1021/ma1004953] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jeong Ae Yoon
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Chakicherla Gayathri
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Roberto R. Gil
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Tomasz Kowalewski
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Krzysztof Matyjaszewski
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
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Perelman LA, Moore T, Singelyn J, Sailor MJ, Segal E. Preparation and characterization of a pH- and thermally responsive poly(N-isopropylacrylamide-co-acrylic acid)/porous SiO(2) hybrid. ADVANCED FUNCTIONAL MATERIALS 2010; 20:826-833. [PMID: 23335870 PMCID: PMC3548441 DOI: 10.1002/adfm.200900822] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
A multifunctional nanohybrid composed of a pH- and thermoresponsive hydrogel, poly(N-isopropylacrylamide-co-acrylic acid), poly(NIPAM-co-AAc) is synthesized in-situ within the mesopores of an oxidized porous Si template. The hybrid is characterized by electron microscopy and by thin film optical interference spectroscopy. The optical reflectivity spectrum of the hybrid displays Fabry-Pérot fringes characteristic of thin film optical interference, enabling direct, real-time observation of the pH- induced swelling and volume phase transitions associated with the confined poly(NIPAM-co-AAc) hydrogel. The optical response correlates to the percentage of AAc contained within the hydrogel, with a maximum change observed for samples containing 20% AAc. The swelling kinetics of the hydrogel are significantly altered due to the nanoscale confinement; displaying a more rapid response to pH or heating stimuli relative to bulk polymer films. The inclusion of AAc dramatically alters the thermoresponsiveness of the hybrid at pH 7, effectively eliminating the lower critical solution temperature (LCST). The observed changes in the optical reflectivity spectrum are interpreted in terms of changes in the dielectric composition and morphology of the hybrids.
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Affiliation(s)
- Loren A Perelman
- Ester Segal, Department of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel, and The Russell Berrie Nanotechnology Institute, Technion - Israel Institute of Technology, Haifa 32000, Israel
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29
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Luo X, Shen K, Luo C, Ji H, Ouyang Q, Chen Y. An automatic microturbidostat for bacterial culture at constant density. Biomed Microdevices 2010; 12:499-503. [DOI: 10.1007/s10544-010-9406-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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30
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Kim P, Kim SJ, Han J, Suh KY. Stabilization of ion concentration polarization using a heterogeneous nanoporous junction. NANO LETTERS 2010; 10:16-23. [PMID: 20017532 PMCID: PMC2806642 DOI: 10.1021/nl9023319] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We demonstrate a recycled ion-flux through heterogeneous nanoporous junctions, which induce stable ion concentration polarization with an electric field. The nanoporous junctions are based on integration of ionic hydrogels whose surfaces are negatively or positively charged for cationic or anionic selectivity, respectively. Such heterogeneous junctions can be matched up in a way to achieve continuous ion-flux operation for stable concentration gradient or ionic conductance. Furthermore, the combined junctions can be used to accumulate ions on a specific region of the device.
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Affiliation(s)
- Pilnam Kim
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, 151-742, Korea
| | - Sung Jae Kim
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Jongyoon Han
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Corresponding author: : or
| | - Kahp Y. Suh
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, 151-742, Korea
- World Class University Program on Multiscale Mechanical Design, Seoul National University, Seoul, 151-742, Korea
- Corresponding author: : or
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31
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Kim D, Lokuta MA, Huttenlocher A, Beebe DJ. Selective and tunable gradient device for cell culture and chemotaxis study. LAB ON A CHIP 2009; 9:1797-800. [PMID: 19495465 PMCID: PMC2804468 DOI: 10.1039/b901613a] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
This article describes a microfluidic device for cell culture and chemotaxis studies under various temporal and spatial concentration gradients of the medium or chemoattractant. Vertical membranes formed using in situ fabrication are employed to avoid fluid flow inside the cell observation chamber. Thus, the medium and chemoattractants are primarily provided by diffusion, maintaining cell-cell communication via secreted factors. Neutrophils were used to demonstrate the capability of the device for chemotaxis research. Experiments exhibited successful migration up a concentration gradient of interleukin 8.
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Affiliation(s)
- Dongshin Kim
- Department of Mechanical Engineering, University of Wisconsin, Madison, WI, 53706, USA
- Department of Biomedical Engineering, University of Wisconsin, 2142 Engineering Centers Building, 1550 Engineering Drive, Madison, WI, 53706, USA
| | - Mary A. Lokuta
- Department of Pediatrics, 4205 Microbial Sciences Building, 1550 Linden Dr, Madison, WI, 53706, USA
| | - Anna Huttenlocher
- Department of Pediatrics, 4205 Microbial Sciences Building, 1550 Linden Dr, Madison, WI, 53706, USA
- Department of Pharmacology, University of Wisconsin, Madison, WI, 53706 USA
| | - David J. Beebe
- Department of Mechanical Engineering, University of Wisconsin, Madison, WI, 53706, USA
- Department of Biomedical Engineering, University of Wisconsin, 2142 Engineering Centers Building, 1550 Engineering Drive, Madison, WI, 53706, USA
- ; Tel: (+608) 262-2260
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Ehrick JD, Luckett MR, Khatwani S, Wei Y, Deo SK, Bachas LG, Daunert S. Glucose Responsive Hydrogel Networks Based on Protein Recognition. Macromol Biosci 2009; 9:864-8. [DOI: 10.1002/mabi.200800337] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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33
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Dissecting microbiological systems using materials science. Trends Microbiol 2009; 17:100-8. [DOI: 10.1016/j.tim.2008.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 11/18/2008] [Accepted: 11/24/2008] [Indexed: 11/15/2022]
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Abstract
Complex systems require their distinct components to function in a dynamic, integrated, and cooperative fashion. To accomplish this in current microfluidic networks, individual valves are often switched and pumps separately powered by using macroscopic methods such as applied external pressure. Direct manipulation and control at the single-device level, however, limits scalability, restricts portability, and hinders the development of massively parallel architectures that would take best advantage of microscale systems. In this article, we demonstrate that local geometry combined with a simple global field can not only reversibly drive component assembly but also power distinct devices in a parallel, locally uncoupled, and integrated fashion. By employing this single approach, we assemble and demonstrate the operation of check valves, mixers, and pistons within specially designed microfluidic environments. In addition, we show that by linking these individual components together, more complex devices such as pumps can be both fabricated and powered in situ.
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Kwon GH, Park JY, Kim JY, Frisk ML, Beebe DJ, Lee SH. Biomimetic soft multifunctional miniature aquabots. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2008; 4:2148-53. [PMID: 18989854 DOI: 10.1002/smll.200800315] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Affiliation(s)
- Gu Han Kwon
- Department of Biomedical Engineering, College of Health Science, Korea University, Jeongneung-dong, Seongbuk-gu, Seoul 136-703, Republic of Korea
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36
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Kim D, Beebe DJ. Interfacial formation of porous membranes with poly(ethylene glycol) in a microfluidic environment. J Appl Polym Sci 2008. [DOI: 10.1002/app.27890] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Shinohara SI, Seki T, Sakai T, Yoshida R, Takeoka Y. Chemical and optical control of peristaltic actuator based on self-oscillating porous gel. Chem Commun (Camb) 2008:4735-7. [DOI: 10.1039/b808427k] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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38
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Polymer microfabrication technologies for microfluidic systems. Anal Bioanal Chem 2007; 390:89-111. [DOI: 10.1007/s00216-007-1692-2] [Citation(s) in RCA: 467] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 10/05/2007] [Accepted: 10/09/2007] [Indexed: 01/11/2023]
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39
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Shankar BV, Patnaik A. A New pH and Thermo-Responsive Chiral Hydrogel for Stimulated Release. J Phys Chem B 2007; 111:9294-300. [PMID: 17629325 DOI: 10.1021/jp073275a] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chirality of the amphiphile to promote gelation in the given solvent medium is narrated in a new catanionic surfactant mixture from a twin-chiral, twin-tailed surfactant derived from tartaric acid and cetyltrimethylammonium bromide (CTAB). The surfactant bis(decyloxy) succinic acid (BDSA), a chiral Gemini-type surfactant with a rigid spacer, in association with CTAB formed pH and temperature responsive vesicles and hydrogels. Molecular chirality gave rise to supertwisted fibrillar hydrogels at a BDSA:CTAB molar ratio of 1:2 and in 31% water content. The hydrogels from enantiomeric BDSA were reversibly pH and irreversibly temperature responsive at pH<6.2 and at 55 degrees C, respectively, whereas the corresponding sodium succinates formed transparent clear gels reversible to both pH and temperature. The hydrogels were able to entrap and release model dye molecules, Rhodamine B, and Congo red, responding to thermal and pH stimuli. Circular dichroism unraveled the chiro-optical behavior of the assembled fibers, allowing monitoring of aggregation and packing. The presence and the relative configuration of the stereogenic centers in the structure of this low molecular weight gelator have been observed to be critical to form gels. The high curvature Gaussian gel network was modeled based on the chiral elastic membrane approach and the pitch angle of the Gaussian twist was estimated to be 45 degrees.
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Affiliation(s)
- B Vijai Shankar
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India
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