APPLICATIONS OF OLIGOPEPTIDE-FUNCTIONALIZED SURFACES AND MICROPARTICLES IN LIQUID CRYSTALS-BASED ASSAYS

Abstract

Liquid crystals- (LC-) based protease assays are attractive due to its sensitive and multiplexed detection format. However, several key challenges remained. In this study, various strategies were developed to address these issues. Firstly, cysteine-labeled oligopeptides were synthesized for immobilization on solid surfaces, which provide a stable platform for subsequent hydrolysis of oligopeptides by proteases. However, such hydrolysis only causes minute changes to surface topography. Alternatively, bi-cysteine-bearing, biotin-labeled peptides can be used as protease substrates. These peptides have a higher immobilization density and better stability, whereas the biotin moiety offers a streptavidin binding site for amplification of protease activity. Thirdly, microparticles with a high surface area were used as a new platform for protease assays. Surfaces of microparticles were functionalized with octadecyl- (C18)-labeled oligopeptides, which can be cleaved by proteases and influence orientations of LC. Finally, functionalized microparticles assembled at LC/water interfaces are exploited as a functional real-time enzyme sensor.