Poly(-isopropylacrylamide) (PNIPAM) microgel is a smart polymer that shows a volume phase transition temperature (VPTT) at around 32 °C in aqueous solutions, above which it collapses. In this work, combining experiments and molecular simulations, it is shown that PNIPAM microgels do not always exhibit a collapsed structure above the VPTT. Instead, PNIPAM in aqueous alcohol mixtures shows a two-step conformational transition, i.e., a collapse at low temperatures ( < 32 °C) and a reswelling when > 50 °C. The present analysis indicates that delicate microscopic interaction details, together with the bulk solution properties, play a key role in dictating the reswelling behavior. Even when PNIPAM microgels swell with increasing , this is not a standard upper critical solution behavior.
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Small
January 2025
DWI-Leibniz Institute for Interactive Materials e.V., RWTH Aachen University, Forckenbeckstr. 50, 52074, Aachen, Germany.
Compartmentalization is crucial for control over complex biological cascade reactions. In microgels, the formation of discrete compartments allows for simultaneous uptake and orthogonal release of physicochemically distinct drugs, among others. However, many state-of-the-art approaches yielding compartmentalized microgels require the use of specific, though not always biocompatible, components and temperatures well above the physiological range, which may damage possible biological cargo.
View Article and Find Full Text PDFAnal Chim Acta
February 2025
Department of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India; Department of Applied Chemistry, Maulana Abul Kalam Azad University of Technology, Simhat, Haringhata, West Bengal, 741249, India. Electronic address:
Background: The intellectual progress in fabricating artificial probes for selective appraisal of biologically admissible amino acids has displayed exponential growth in recent era.The neoteric era in material science has witnessed the significant application of carbon quantum dots (CQDs). However, the hybrid microgel of CQDs was less explored.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Chemistry Department, Lomonosov Moscow State University, Moscow 119991, Russia.
Polymer-based aqueous redox flow batteries (RFBs) are attracting increasing attention as a promising next-generation energy storage technology due to their potential for low cost and environmental friendliness. The search for new redox-active organic compounds for incorporation into polymer materials is ongoing, with anolyte-type compounds in high demand. In response to this need, we have synthesized and tested a range of new water-soluble redox-active s-tetrazine derivatives, including both low molecular weight compounds and polymers with different architectures.
View Article and Find Full Text PDFLangmuir
January 2025
Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India.
Herein, we present a novel liquid crystal (LC)-based sensing platform utilizing microgel-stabilized Pickering LC droplets dispersed in water for simple and label-free detection of proteins in an aqueous environment. This could be achieved by tailoring the surface of 4-cyano-4'-pentylbiphenyl (5CB) LC droplets dispersed in aqueous medium through the interfacial adsorption of poly(-isopropylacrylamide) (PNIPAM) microgel particles, followed by the introduction of model surfactants, such as anionic sodium dodecyl sulfate and cationic dodecyltrimethylammonium bromide. These surfactant/microgel complex-coated LC droplets underwent a configurational transition from radial-to-bipolar under a polarized optical microscope, upon exposure to model proteins, namely bovine serum albumin and lysozyme.
View Article and Find Full Text PDFGels
December 2024
Faculty of Chemical Sciences and Engineering, Autonomous University of Baja California, University Boulevard No. 14418, Otay Mesa, Tijuana 22390, Mexico.
This study aims to design microgels that are thermo- and pH-sensitive for controlled doxorubicin (Dox) release in response to tumor microenvironment changes. N-isopropylacrylamide (NIPAAm) is widely used for thermoresponsive tumor-targeted drug delivery systems for the release of therapeutic payloads in response to temperature changes. Herein, a NIPAAm microgel (MP) that is responsive to temperature and pH was designed for the smart delivery of Dox.
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