Ultra-stable liquid crystal droplets coated by sustainable plant-based materials for optical sensing of chemical and biological analytes.

Herein, we demonstrate for the first time the synthesis of ultra-stable, spherical, nematic liquid crystal (LC) droplets of narrow size polydispersity coated by sustainable, biodegradable, plant-based materials that trigger a typical bipolar-to-radial configurational transition in dynamic response to chemical and biological analytes. Specifically, a highly soluble polymer, potato protein (PoP) and a physically-crosslinked potato protein microgel (PoPM) of ∼100 nm in diameter, prepared from the PoP, a byproduct of the starch industry, were compared for their ability to coat LC droplets. Although both PoP and PoPM were capable of reducing the interfacial tension between water and -tetradecane <30 mN m, PoPM-coated LC droplets showed better stability than the PoP-coated droplets a Pickering-like mechanism.

Chitosan Hydrogels with Embedded Thermo- and pH-Responsive Microgels as a Potential Carrier for Controlled Release of Drugs.

We report a promising strategy based on chitosan (CS) hydrogels and dual temperature- and pH-responsive poly(-isopropylacrylamide--methacrylic acid) (PNIPAM--MAA) microgels to facilitate release of a model drug, moxifloxacin (MFX). In this protocol, first, the microgels were prepared using a free radical copolymerization method, and subsequently, these carboxyl-group-rich soft particles were incorporated inside the hydrogel matrix using an EDC-NHS amidation method. Interestingly, the resulting microgel-embedded hydrogel composites (MG-HG) acting as a double barrier system largely reduced the drug release rate and prolonged the delivery time for up to 68 h, which was significantly longer than that obtained using microgels or hydrogels alone (20 h).

Temperature- and pH-responsive poly(-isopropylacrylamide--methacrylic acid) microgels as a carrier for controlled protein adsorption and release.

Herein, we report controlled protein adsorption and delivery of thermo- and pH-responsive poly(-isopropylacrylamide--methacrylic acid) (PNIPAM--MAA) microgels at different temperatures, pH values and ionic strengths by employing bovine serum albumin (BSA) as a model protein. For these dual-responsive microgels, we found that the BSA adsorption was driven by several of six competing contributions, , physical diffusion (PD), hydrophobic interactions (HI), electrostatic attraction (EA), hydrogen bonding (HB) and temperature or pH-induced seizing action (SA or SA), depending on the temperature and pH of the solution. Compared to the pure PNIPAM microgels, the higher swelling degree of the PNIPAM--MAA microgels allowed a large amount of BSA loading under any experimental conditions.

Protein Microgel-Stabilized Pickering Liquid Crystal Emulsions Undergo Analyte-Triggered Configurational Transition.

Herein, we report a novel approach that involves Pickering stabilization of micometer-sized liquid crystal (LC) droplets with biocompatible soft materials such as a whey protein microgel (WPM) to facilitate the analysis of analyte-induced configurational transition of the LC droplets. The WPM particles were able to irreversibly adsorb at the LC-water interface, and the resulting WPM-stabilized LC droplets possessed a remarkable stability against coalescence over time. Although the LC droplets were successfully protected by a continuous network of the WPM layer, the LC-water interface was still accessible for small molecules such as sodium dodecyl sulfate (SDS) that could diffuse through the meshes of the adsorbed WPM network or through the interfacial pores and induce an LC response.