(634f) Pickering Emulsions of Thermotropic Liquid Crystals for Sensing Phospholipid Membranes

Liquid crystal (LC) emulsions in water provide a versatile platform for designing biosensors that respond sensitively to the presence of analytes (e.g., phospholipids, microbial cells) in aqueous environments. However, LC droplets coalesce over time (e.g., within hours), which creates technical challenges related to long-term storage and accurate analyte detection in practical applications. Recently, we showed that Pickering stabilization approaches based on the use of surface-modified nanoparticles that adsorb to LC droplet interfaces to prevent coalescence lead to substantially improved shelf-life of LC emulsions (i.e., at least three months up to one year after preparation). This presentation will describe our recent studies aimed at characterizing the LC ordering transitions of nanoparticle-stabilized LC droplets upon exposure to model phospholipid membranes of various compositions. These LC droplets respond to small unilamellar vesicles (SUVs) present in the surrounding aqueous medium, as evidenced by changes in LC droplet configurations that are similar to those observed in bare-droplet LC emulsions. Moreover, our results reveal significant differences in the sensitivity of response of these nanoparticle-stabilized LC droplets to SUVs, in ways that depend upon phospholipid structure and charge. Overall, our results show that Pickering stabilization of LC emulsions using surface-modified nanoparticles provides a promising platform for developing biosensors with long-term shelf-life stability, as well as opportunities to tune the sensitivity and selectivity of response to target phospholipid membranes.