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. Self‐assembly of nitrilotriacetic acid terminated amphiphiles loaded with Ni2+ ions at aqueous‐liquid crystal interface creates a surface capable of immobilizing histidine‐tagged ubiquitin through complex formation between Ni2+ and histidine. When these surfaces containing immobilized histidine‐tagged 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.

Conformational Changes of Acyl Carrier Protein Switch the Chain Length Preference of Acyl-ACP Thioesterase ChFatB2

“…Isothermal titration calorimetry method was introduced but failed due to the weak reaction heat. Liquid crystals with a special physical and optical property can be used to report chemical and biomolecular binding events (such as the binding of the target protein and the ligand) through their orientational behaviors and the corresponding optical textures [ 25 , 26 , 27 ]. Then the semi-quantitative method was applied to investigate their interactions.…”

Imaging Trypsin Activity through Changes in the Orientation of Liquid Crystals Coupled to the Interactions between a Polyelectrolyte and a Phospholipid Layer

“…LCs laden with a phospholipid monolayer were prepared following procedures published in previous literature. ,,, DOPG dissolved in chloroform was dried with N 2 gas and placed under vacuum for at least 3 h. The dried phospholipid then was resuspended with PBS to a final concentration of 1 mM. Next, the phospholipid suspension was sonicated three times each for 5 min at room temperature to obtain a clear solution.…”

Polarizer-Free Dye-Doped Liquid Crystal Sensors with High Precision

“…While DDLCs are widely used in display technologies, 58−61 DDLC-based approach excels in detecting analytes in the presence or absence of fluid flow by using SDS as a model compound that is representative of a wide range of amphiphilic analytes. [16][17][18][19][20]41 The versatility of the DDLC approach makes it applicable to any previously reported LC sensor design, including those involving detection of nonamphiphilic analytes (e.g., proteins and peptides [32][33][34]37,38 ) and contexts with random or biased in-plane LC orientations.…”