Liquid Crystals that Respond to the Aqueous Phase Reactions Catalyzed by Synthetic Enzyme Mimics

Abstract

Liquid crystal (LC)-aqueous soft interface sensors have shown potential toward a wide range of analytes, which also include tracking of their reactions. While these sensors have shown promise in studying enzymatic activity, they have been limited to natural enzymes. A whole-synthetic approach is introduced for the detection of molecular species through their interactions with enzyme mimics. Highly stable and robust, fullerene-based synthetic enzyme mimics are employed, and the response of nematic LC droplets to their hydrolysis activity is investigated. This involves characterizing the structures of the LC droplets in the aqueous phase that facilitate enzymatic reactions, monitoring the responses of LC droplets to these interactions to sense enzymatic activity. Polarized light microscopy is employed to image the LC droplets, spectrophotometry to measure kinetics, and interfacial tension measurements for structural characterization of LC interfaces. These findings revealed an instantaneous response of the LC droplets that originate from the enzyme mimic-substrate interactions in the bulk phase, and the presence of the LC droplets does not noticeably influence the function and interactions of the enzyme mimics. These findings offer a new perspective on LC-based sensing systems that can be tailored to a wide range of substrates or enzyme-substrate interactions.