Decorating liquid crystal surfaces with proteins for real-time detection of specific protein-protein binding

Abstract

Here, a novel method of immobilizing proteins with well-defined orientation directly on liquid crystal surfaces that allow subsequent real-time imaging of specific protein-protein binding events on these surfaces is reported. Selfassembly of nitrilotriacetic acid terminated amphiphiles loaded with Ni 2+ ons at aqueous-liquid crystal interface creates a surface capable of immobilizing histidine-tagged ubiquittn through complex formation between Ni2+ and histidine. When these surfaces containing immobilized histidinetagged ubiquitin are exposed to anti-ubiquitin antibody, the spatial and temporal of specific protein-protein binding events trigger orientational transitions of liquid crystals. As a result, sharp liquid crystal optical switching from dark to bright can readily be observed under polarized lighting. The protein-protein binding can be observed within seconds and only requires nanogram quantities of proteins. This work demonstrates a simple strategy to immobilize proteins with well-defined orientation on liquid crystal surfaces for real-time and label-free detection of specific protein-protein binding events, which may find use in biomedical diagnostics © 2009 WILEY-VCH Verlag GmbH & Co. KGaA.