Liquid Crystal Reorientation Induced by Aptamer Conformational Changes

Abstract

Aptamer-ligand binding events, involving small molecule targets, at a surfactant-laden aqueous/liquid crystal (LC) interface were found to trigger a LC reorientation that can be observed in real-time using polarized light. The response was both sensitive and selective: reorientation was observed at target concentrations on the order of the aptamer dissociation constant, but no response was observed in control experiments with target analogues. Circular dichroism and resonance energy transfer experiments suggested that the LC reorientation was due to a conformational change of the aptamer upon target binding. Specifically, under conditions where aptamer-ligand binding induced a conformational change from a relaxed random coil to more intricate secondary structures (e.g., double helix, G-quadruplex), a transition from planar to homeotropic LC orientation was observed. These observations suggest the potential for a label-free LC-based detection system that can simultaneously respond to the presence of both small molecules and nucleic acids.

Liquid crystal elastomer actuators: Synthesis, alignment, and applications

“…Liquid crystal researchers have also begun turning to the biological fields to find application. Low molecular weight liquid crystals have been used as biological sensors for detecting specific aptamers or glucose levels . Bera et al has already used liquid crystal elastomer microspheres and scaffolds to culture cells for mimicry of the 3D tissue environment.…”

Adsorption of rationally designed “surf-tides” to a liquid-crystal interface

“…8,12,14 Future studies will aim to address several key characteristics mentioned throughout this work, specifically: (1) optimize and further improve the sensitivity of the experimental setup to allow the detection of decreased analyte concentrations (2) examine the role that overall net charge has on the sensitivity and dynamics of interfacial adsorption by synthesizing ''inverse'' peptides with opposing charges at the same residue locations while keeping the surfactant constant (3) investigate the adsorption of peptides into insoluble layers (i.e. The LC experimental platform shows sufficient sensitivity to optically observe molecular adsorption of two very similar molecules over macroscopic length scales.…”

“…birefringence) with incident light not seen in isotropic fluids while still maintaining fluid-like behavior. Additionally, such systems allow for the transduction of highly specific molecular interactions including ssDNA complement interactions, 12 enzymatic ''lock and key'' activity, 13 aptamer pairing, 14 and protein receptor-ligand binding. 9 The configurations simultaneously permit the development of highly complex assemblies consisting of several discrete layers that mimic naturally occurring (i.e.…”

Modelling and Development of Electrical Aptasensors: A Short Review

“…Moreover, this technique seems able to generate aptamers for virtually each possible target [2], overcoming the needs for cell lines or animals [1]. To date, numerous high-affinity aptamers have been selected for a broad range of target molecules, including metal ions, peptides, drugs, proteins and even whole cells or viruses [1,3,4]. Finally, aptamers are very stable and can recover their active conformation after denaturation at high temperature [1].…”