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Piñeres-Quiñones OH, Oñate-Socarras MK, Wang F, Lynn DM, Acevedo-Vélez C. Pickering Emulsions of Thermotropic Liquid Crystals Stabilized by Amphiphilic Gold Nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 38320298 DOI: 10.1021/acs.langmuir.3c03940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
We report emulsions of thermotropic liquid crystals (LCs) in water that are stabilized using amphiphilic gold nanoparticles (AuNPs) and retain their ability to respond to aqueous analytes for extended periods (e.g., up to 1 year after preparation). These LC emulsions exhibit exceptional colloidal stability that results from the adsorption of AuNPs that are functionalized with thiol-terminated poly(ethylene glycol) (PEG-thiol) and hexadecanethiol (C16-thiol) to LC droplet interfaces. These stabilized LC emulsions respond to the presence of model anionic (SDS), cationic (C12TAB), and nonionic (C12E4) surfactants in the surrounding aqueous media, as evidenced by ordering transitions in the LC droplets that can be readily observed using polarized light microscopy. Our results reveal significant differences in the sensitivity of the stabilized LC droplets toward each of these analytes. In particular, these stabilized droplets can detect the cationic C12TAB at concentrations that are lower than those required for bare LC droplets under similar experimental conditions (0.5 and 2 mM, respectively). These results demonstrate an enhanced sensitivity of the LC toward C12TAB when the PEG/C16-thiol-coated AuNPs are adsorbed at LC droplet interfaces. In contrast, the concentrations of SDS required to observe optical transformations in the stabilized LC droplets are higher than those required for the bare LC droplets, suggesting that the presence of the PEG/C16-thiol AuNPs reduces the sensitivity of the LC toward this analyte. When combined, our results show that this Pickering stabilization approach using amphiphilic AuNPs as stabilizing agents for LC-in-water emulsions provides a promising platform for developing LC droplet-based optical sensors with long-term colloidal stability as well as opportunities to tune the sensitivity and selectivity of the response to target aqueous analytes.
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Affiliation(s)
- Oscar H Piñeres-Quiñones
- Department of Chemical Engineering, University of Puerto Rico-Mayagüez, Call Box 9000, Mayagüez, PR 00681-9000, United States
| | - Maria K Oñate-Socarras
- Department of Chemical Engineering, University of Puerto Rico-Mayagüez, Call Box 9000, Mayagüez, PR 00681-9000, United States
| | - Fengrui Wang
- Department of Chemistry, 1101 University Avenue, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
| | - David M Lynn
- Department of Chemistry, 1101 University Avenue, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
- Department of Chemical and Biological Engineering, 1415 Engineering Drive, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
| | - Claribel Acevedo-Vélez
- Department of Chemical Engineering, University of Puerto Rico-Mayagüez, Call Box 9000, Mayagüez, PR 00681-9000, United States
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2
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Wang F, Qin S, Acevedo-Vélez C, Van Lehn RC, Zavala VM, Lynn DM. Decoding Optical Responses of Contact-Printed Arrays of Thermotropic Liquid Crystals Using Machine Learning: Detection and Reporting of Aqueous Amphiphiles with Enhanced Sensitivity and Selectivity. ACS APPLIED MATERIALS & INTERFACES 2023; 15:50532-50545. [PMID: 37856671 DOI: 10.1021/acsami.3c12905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Surfactants and other amphiphilic molecules are used extensively in household products, industrial processes, and biological applications and are also common environmental contaminants; as such, methods that can detect, sense, or quantify them are of great practical relevance. Aqueous emulsions of thermotropic liquid crystals (LCs) can exhibit distinctive optical responses in the presence of surfactants and have thus emerged as sensitive, rapid, and inexpensive sensors or reporters of environmental amphiphiles. However, many existing LC-in-water emulsions require the use of complicated or expensive instrumentation for quantitative characterization owing to variations in optical responses among individual LC droplets. In many cases, the responses of LC droplets are also analyzed by human inspection, which can miss subtle color or topological changes encoded in LC birefringence patterns. Here, we report an LC-based surfactant sensing platform that takes a step toward addressing several of these issues and can reliably predict concentrations and types of surfactants in aqueous solutions. Our approach uses surface-immobilized, microcontact-printed arrays of micrometer-scale droplets of thermotropic LCs and hierarchical convolutional neural networks (CNNs) to automatically extract and decode rich information about topological defects and color patterns available in optical micrographs of LC droplets to classify and quantify adsorbed surfactants. In addition, we report computational capabilities to determine relevant optical features extracted by the CNN from LC micrographs, which can provide insights into surfactant adsorption phenomena at LC-water interfaces. Overall, the combination of microcontact-printed LC arrays and machine learning provides a convenient and robust platform that could prove useful for developing high-throughput sensors for on-site testing of environmentally or biologically relevant amphiphiles.
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Affiliation(s)
- Fengrui Wang
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, United States
| | - Shiyi Qin
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, Wisconsin 53706, United States
| | - Claribel Acevedo-Vélez
- Department of Chemical Engineering, University of Puerto Rico-Mayagüez, Call Box 9000, Mayagüez, PR 00681-9000, United States
| | - Reid C Van Lehn
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, Wisconsin 53706, United States
| | - Victor M Zavala
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, Wisconsin 53706, United States
- Mathematics and Computer Science Division, Argonne National Laboratory, 9700 S. Cass Ave, Lemont, Illinois 60439, United States
| | - David M Lynn
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, United States
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, Wisconsin 53706, United States
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3
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Borbora A, Manna U. Design of a Super-Liquid Crystal-Phobic Coating for Immobilizing Liquid Crystal μ-Droplets─Without Affecting Their Sensitivity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:9221-9228. [PMID: 35767825 DOI: 10.1021/acs.langmuir.2c01005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The aqueous interface of nematic liquid crystal (LC) that undergoes a triggered change in ordering transition of mesogens under an appropriate stimulus has emerged as an important tool for various relevant applications. Further, the confinement of LC into a micrometer dimension appeared to be a facile approach for improving their relevant features and performance. However, the optical characterization of ordering transition in a single micrometer-sized, bare, and free-floating LC droplet in the aqueous phase is an extremely challenging task due to unavoidable Brownian motion, which limits its scope for practical applications. Here, we exploited the 1,4-conjugate addition reaction to report a multilayer coating of a reactive nanocomplex that displayed an extreme repellence to beaded LC droplets with tailored adhesive force through the association of adequate orthogonal chemical modifications with glucamine and selected alkyl acrylates. Further, a spatially selective underwater adhesive super-LC-phobic pattern on a hydrophobic background was developed for immobilizing bare and micrometer-sized LC droplets from their aqueous dispersion without having any arbitrary spillage of the aqueous medium. The settled micrometer-sized LC droplets remained efficient for the triggered change in ordering transition from bipolar (having boojum defects at poles) to radial (with a single defect in the center) configuration. Eventually, a simple and fundamentally distinct chemical strategy of immobilizing a soft and functional material by associating bio-inspired wettability allowed to demonstrate the repetitive triggered LC ordering transition in a single and bare LC droplet.
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Affiliation(s)
- Angana Borbora
- Bio-Inspired Polymeric Materials Lab, Department of Chemistry, Indian Institute of Technology, Guwahati, Kamrup, Assam 781039, India
| | - Uttam Manna
- Bio-Inspired Polymeric Materials Lab, Department of Chemistry, Indian Institute of Technology, Guwahati, Kamrup, Assam 781039, India
- Centre for Nanotechnology, Indian Institute of Technology, Guwahati, Kamrup, Assam 781039, India
- Jyoti and Bhupat Mehta School of Health Science & Technology, Indian Institute of Technology, Guwahati, Kamrup, Assam 781039, India
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4
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Label-free optical sensor based on liquid crystal sessile droplet array for penicillin G determination. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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5
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Piñeres-Quiñones OH, Lynn DM, Acevedo-Vélez C. Environmentally Responsive Emulsions of Thermotropic Liquid Crystals with Exceptional Long-Term Stability and Enhanced Sensitivity to Aqueous Amphiphiles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:957-967. [PMID: 35001623 DOI: 10.1021/acs.langmuir.1c02278] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We report colloidally stable emulsions of thermotropic liquid crystals (LCs) that can detect the presence of amphiphilic analytes in aqueous environments. Our approach makes use of a Pickering stabilization strategy consisting of surfactant-nanoparticle complexes (SiO2/CnTAB, n = 8, 12, 16) that adsorb to aqueous/LC droplet interfaces. This strategy can stabilize LC emulsions against coalescence for at least 3 months. These stabilized LC emulsions also retain the ability to respond to the presence of model anionic, cationic, and nonionic amphiphiles (e.g., SDS, C12TAB, C12E4) in aqueous solutions by undergoing "bipolar-to-radial" changes in LC droplet configurations that can be readily observed and quantified using polarized light microscopy. Our results reveal these ordering transitions to depend upon the length of the hydrocarbon tail of the CnTAB surfactant used to form the stabilizing complexes. In general, increasing CnTAB surfactant tail length leads to droplets that respond at lower analyte concentrations, demonstrating that this Pickering stabilization strategy can be used to tune the sensitivities of the stabilized LC droplets. Finally, we demonstrate that these colloidally stable LC droplets can report the presence of rhamnolipid, a biosurfactant produced by the bacterial pathogen Pseudomonas aeruginosa. Overall, our results demonstrate that this Pickering stabilization strategy provides a useful tool for the design of LC droplet-based sensors with substantially improved colloidal stability and new strategies to tune their sensitivities. These advances could increase the potential practical utility of these responsive soft materials as platforms for the detection and reporting of chemical and biological analytes.
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Affiliation(s)
- Oscar H Piñeres-Quiñones
- Department of Chemical Engineering, University of Puerto Rico-Mayagüez, Call Box 9000, Mayagüez, Puerto Rico 00681-9000, United States
| | - David M Lynn
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, United States
| | - Claribel Acevedo-Vélez
- Department of Chemical Engineering, University of Puerto Rico-Mayagüez, Call Box 9000, Mayagüez, Puerto Rico 00681-9000, United States
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6
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Manna U, Zavala YM, Abbott NL, Lynn DM. Structured Liquid Droplets as Chemical Sensors that Function Inside Living Cells. ACS APPLIED MATERIALS & INTERFACES 2021; 13:42502-42512. [PMID: 34469102 DOI: 10.1021/acsami.1c12667] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We report that micrometer-scale droplets of thermotropic liquid crystals (LCs) can be positioned inside living mammalian cells and deployed as chemical sensors to report the presence of toxins in extracellular environments. Our approach exploits droplets of LC enclosed in semi-permeable polymer capsules that enable internalization by cells. The LC droplets are stable in intracellular environments, but undergo optical changes upon exposure of cells to low, sub-lethal concentrations of toxic amphiphiles. Remarkably, LC droplets in intracellular environments respond to extracellular analytes that do not generate an LC response in the absence of cellular internalization. They also do not respond to other chemical stimuli or processes associated with cell growth or manipulation in culture. Our results suggest that droplet activation involves the transport and co-adsorption of amphiphilic toxins and other lipophilic cell components to the surfaces of internalized droplets. This work provides fundamentally new designs of biotic-abiotic systems that can report sensitively and selectively on the presence of select chemical agents outside cells and provides a foundation for the design of structured liquid droplets that can sense and report on other biochemical or metabolic processes inside cells.
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Affiliation(s)
- Uttam Manna
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, Wisconsin 53706, United States
| | - Yashira M Zavala
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, Wisconsin 53706, United States
| | - Nicholas L Abbott
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, Wisconsin 53706, United States
| | - David M Lynn
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, Wisconsin 53706, United States
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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7
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Borbora A, Manna U. Impact of chemistry on the preparation and post-modification of multilayered hollow microcapsules. Chem Commun (Camb) 2021; 57:2110-2123. [PMID: 33587065 DOI: 10.1039/d0cc06917e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In the last few years, various chemical bondings and interactions were rationally adopted to develop different multilayered microcapsules, where the empty interior accommodated various important cargoes, including bioactive molecules, nanoparticles, antibodies, enzymes, etc., and the thin membrane protected/controlled the release of the loaded cargo. Eventually, such materials are with immense potential for a wide range of prospective applications related to targeted drug delivery, sensing, bio-imaging, developing biomimetic microreactors, and so on. The emphasis on the use of various chemistries for the development of functional and useful microcapsules is rarely illustrated in the literature in the past. In this feature article, the rational uses of different chemistries for (a) preparing and (b) post-modifying various functional microcapsules are accounted. The appropriate selection of chemical bondings/interactions, including electrostatic interaction, host-guest interaction, hydrogen bonding, and covalent bonding, allowed the integration of essential constituents during the layer-by-layer deposition process for 'in situ' tailoring of the relevant and diverse properties of the hollow microcapsules. Recently, different chemically reactive hollow microcapsules were also introduced through the strategic association of 'click chemistry', ring-opening azlactone reaction, thiol-ene reaction, and 1,4-conjugate addition reaction for facile and desired post covalent modifications of the multilayer membrane. The strategic selection of chemistry remained as the key basis to synthesize smart and useful microcapsules.
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Affiliation(s)
- Angana Borbora
- Bio-Inspired Polymeric Materials Lab, Department of Chemistry, Indian Institute of Technology-Guwahati, Kamrup, Assam 781039, India
| | - Uttam Manna
- Bio-Inspired Polymeric Materials Lab, Department of Chemistry, Indian Institute of Technology-Guwahati, Kamrup, Assam 781039, India and Centre for Nanotechnology, Indian Institute of Technology-Guwahati, Kamrup, Assam 781039, India.
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8
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Ortiz BJ, Boursier ME, Barrett KL, Manson DE, Amador-Noguez D, Abbott NL, Blackwell HE, Lynn DM. Liquid Crystal Emulsions That Intercept and Report on Bacterial Quorum Sensing. ACS APPLIED MATERIALS & INTERFACES 2020; 12:29056-29065. [PMID: 32484648 PMCID: PMC7343617 DOI: 10.1021/acsami.0c05792] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We report aqueous emulsions of thermotropic liquid crystals (LCs) that can intercept and report on the presence of N-acyl-l-homoserine lactones (AHLs), a class of amphiphiles used by pathogenic bacteria to regulate quorum sensing (QS), monitor population densities, and initiate group activities, including biofilm formation and virulence factor production. The concentration of AHL required to promote "bipolar" to "radial" transitions in micrometer-scale droplets of the nematic LC 4'-pentyl-cyanobiphenyl (5CB) decreases with increasing carbon number in the acyl tail, reaching a threshold concentration of 7.1 μM for 3-oxo-C12-AHL, a native QS signal in the pathogen Pseudomonas aeruginosa. The LC droplets in these emulsions also respond to biologically relevant concentrations of the biosurfactant rhamnolipid, a virulence factor produced by communities of P. aeruginosa under the control of QS. Systematic studies using bacterial mutants support the conclusion that these emulsions respond selectively to the production of rhamnolipid and AHLs and not to other products produced by bacteria at lower (subquorate) population densities. Finally, these emulsions remain configurationally stable in growth media, enabling them to be deployed either in bacterial supernatants or in situ in bacterial cultures to eavesdrop on QS and report on changes in bacterial group behavior that can be detected in real time using polarized light. Our results provide new tools to detect and report on bacterial QS and virulence and a materials platform for the rapid and in situ monitoring of bacterial communication and resulting group behaviors in bacterial communities.
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Affiliation(s)
- Benjamín J Ortiz
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Michelle E Boursier
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Kelsey L Barrett
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, Wisconsin 53706, United States
| | - Daniel E Manson
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Daniel Amador-Noguez
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, Wisconsin 53706, United States
| | - Nicholas L Abbott
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - David M Lynn
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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9
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He Y, Zhou Q, Wang S, Yang R, Jiang C, Yuan W. In Situ Observation of Dynamic Wetting Transition in Re-Entrant Microstructures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:3949-3953. [PMID: 28394611 DOI: 10.1021/acs.langmuir.7b00256] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Re-entrant microstructures exhibit excellent wetting stability under different pressure levels, but the underlying mechanism determined by wetting transition behavior at the microscale level remains unclear. We propose the "wetting chip" method for in situ assessment of the dynamic behavior of wetting transition in re-entrant microstructures. High sag and transverse depinning were observed in re-entrant microstructures. Analysis indicated that high sag and transverse depinning mainly influenced the stability of the structures. The threshold pressure and longevity of wetting transition were predicted and experimentally verified. The design criteria of wetting stability, including small geometry design, hydrophobic material selection, and sidewall condition, were also presented. The proposed method and model can be applied to different shapes and geometry microstructures to elucidate wetting stability.
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Affiliation(s)
- Yang He
- Key Laboratory of Micro/Nano Systems for Aerospace, Ministry of Education and Shaan'xi Key Provincial Laboratory of Micro and Nano Electromechanical Systems, Northwestern Polytechnical University , Xi'an 710072, P. R. China
| | - Qingqing Zhou
- Key Laboratory of Micro/Nano Systems for Aerospace, Ministry of Education and Shaan'xi Key Provincial Laboratory of Micro and Nano Electromechanical Systems, Northwestern Polytechnical University , Xi'an 710072, P. R. China
| | - Shengkun Wang
- Key Laboratory of Micro/Nano Systems for Aerospace, Ministry of Education and Shaan'xi Key Provincial Laboratory of Micro and Nano Electromechanical Systems, Northwestern Polytechnical University , Xi'an 710072, P. R. China
| | - Ruyuan Yang
- Key Laboratory of Micro/Nano Systems for Aerospace, Ministry of Education and Shaan'xi Key Provincial Laboratory of Micro and Nano Electromechanical Systems, Northwestern Polytechnical University , Xi'an 710072, P. R. China
| | - Chengyu Jiang
- Key Laboratory of Micro/Nano Systems for Aerospace, Ministry of Education and Shaan'xi Key Provincial Laboratory of Micro and Nano Electromechanical Systems, Northwestern Polytechnical University , Xi'an 710072, P. R. China
| | - Weizheng Yuan
- Key Laboratory of Micro/Nano Systems for Aerospace, Ministry of Education and Shaan'xi Key Provincial Laboratory of Micro and Nano Electromechanical Systems, Northwestern Polytechnical University , Xi'an 710072, P. R. China
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10
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Ahmad F, Jamil M, Lee JW, Jee KE, Jeon YJ. Transitions of bipolar to radial orientation of liquid crystal droplets in amphiphilic system of PDLC film. J DISPER SCI TECHNOL 2017. [DOI: 10.1080/01932691.2016.1236267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Farzana Ahmad
- Department of Chemistry, LCD Research Center, Konkuk University, Seoul, Korea
| | - Muhammad Jamil
- Division of Global Business, University College, Konkuk University, Seoul, Korea
- Department of Physics, Konkuk University, Seoul, Korea
| | - Jin Woo Lee
- Display R&D Team, LIVICON Co., Ltd., Daesowon-Myeon, Chungbuk, Korea
| | - Kim Eun Jee
- Department of Chemistry, LCD Research Center, Konkuk University, Seoul, Korea
| | - Young Jae Jeon
- Department of Chemistry, LCD Research Center, Konkuk University, Seoul, Korea
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11
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Lee K, Gupta KC, Park SY, Kang IK. Anti-IgG-anchored liquid crystal microdroplets for label free detection of IgG. J Mater Chem B 2016; 4:704-715. [DOI: 10.1039/c5tb02131f] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
AIgG anchored LC microdroplets showing configurational transition from radial (a) to bipolar (b) upon interaction with IgG.
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Affiliation(s)
- Kyubae Lee
- Department of Polymer Science and Engineering
- Kyungpook National University
- Daegu 702-701
- Republic of Korea
| | - Kailash Chandra Gupta
- Department of Polymer Science and Engineering
- Kyungpook National University
- Daegu 702-701
- Republic of Korea
- Polymer Research Laboratory
| | - Soo-Young Park
- Department of Polymer Science and Engineering
- Kyungpook National University
- Daegu 702-701
- Republic of Korea
| | - Inn-Kyu Kang
- Department of Polymer Science and Engineering
- Kyungpook National University
- Daegu 702-701
- Republic of Korea
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12
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Guo X, Manna U, Abbott NL, Lynn DM. Covalent Immobilization of Caged Liquid Crystal Microdroplets on Surfaces. ACS APPLIED MATERIALS & INTERFACES 2015; 7:26892-903. [PMID: 26562466 DOI: 10.1021/acsami.5b09595] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Microscale droplets of thermotropic liquid crystals (LCs) suspended in aqueous media (e.g., LC-in-water emulsions) respond sensitively to the presence of contaminating amphiphiles and, thus, provide promising platforms for the development of new classes of droplet-based environmental sensors. Here, we report polymer-based approaches to the immobilization of LC droplets on surfaces; these approaches introduce several new properties and droplet behaviors and thus also expand the potential utility of LC droplet-based sensors. Our approach exploits the properties of microscale droplets of LCs contained within polymer-based microcapsule cages (so-called "caged" LCs). We demonstrate that caged LCs functionalized with primary amine groups can be immobilized on model surfaces through both weak/reversible ionic interactions and stronger reactive/covalent interactions. We demonstrate using polarized light microscopy that caged LCs that are covalently immobilized on surfaces can undergo rapid and diagnostic changes in shape, rotational mobility, and optical appearance upon the addition of amphiphiles to surrounding aqueous media, including many useful changes in these features that cannot be attained using freely suspended or surface-adsorbed LC droplets. Our results reveal these amphiphile-triggered orientational transitions to be reversible and that arrays of immobilized caged LCs can be used (and reused) to detect both increases and decreases in the concentrations of model contaminants. Finally, we report changes in the shapes and optical appearances of LC droplets that occur when immobilized caged LCs are removed from aqueous environments and dried, and we demonstrate that dried arrays can be stored for months without losing the ability to respond to the presence of analytes upon rehydration. Our results address practical issues associated with the preparation, characterization, storage, and point-of-use application of conventional LC-in-water emulsions and provide a basis for approaches that could enable the development of new "off-the-shelf" LC droplet-based sensing platforms.
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Affiliation(s)
- Xuanrong Guo
- Department of Chemical and Biological Engineering and ‡Department of Chemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Uttam Manna
- Department of Chemical and Biological Engineering and ‡Department of Chemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Nicholas L Abbott
- Department of Chemical and Biological Engineering and ‡Department of Chemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - David M Lynn
- Department of Chemical and Biological Engineering and ‡Department of Chemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
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13
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Choi Y, Lee K, Gupta KC, Park SY, Kang IK. The role of ligand–receptor interactions in visual detection of HepG2 cells using a liquid crystal microdroplet-based biosensor. J Mater Chem B 2015; 3:8659-8669. [DOI: 10.1039/c5tb01213a] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Optical (a) and polarized (b) micrographs showing orientational transition in a LC microdroplet on contacting with a HepG2 cell in PBS solution.
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Affiliation(s)
- Yuri Choi
- Department of Polymer Science and Engineering
- Kyungpook National University
- Daegu 702-701
- Republic of Korea
| | - Kyubae Lee
- Department of Polymer Science and Engineering
- Kyungpook National University
- Daegu 702-701
- Republic of Korea
| | - Kailash C. Gupta
- Department of Polymer Science and Engineering
- Kyungpook National University
- Daegu 702-701
- Republic of Korea
- Polymer Research Laboratory
| | - Soo-Young Park
- Department of Polymer Science and Engineering
- Kyungpook National University
- Daegu 702-701
- Republic of Korea
| | - Inn-Kyu Kang
- Department of Polymer Science and Engineering
- Kyungpook National University
- Daegu 702-701
- Republic of Korea
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