Thermotropic liquid crystals in the detection of albumins through a microscopic, spectroscopic and computational approach.

Liquid crystals (LCs) are a promising system of molecules for biosensing as a transducing agent for detecting protein human serum albumin (HSA). Herein, we investigate the detection of HSA by a liquid crystal 4'-octyl-4-biphenylcarbonitrile (8CB) intending to develop an LC-based biosensor. The change in the alignment of liquid crystal molecules in the presence of protein results in the transfigurations of the director through interactions. The limit of 8CB to detect HSA is found to be at a reliable concentration in the development of biosensors. The transition in the director configurations from radial to bipolar during the crystalline to the isotropic phase of the liquid crystals are studied under polarizing optical microscopy. These transitions confirm the detection of HSA by 8CB. The docking analysis depicts the interactions by which 8CB liquid crystal molecules bind with protein HSA. The binding energy, binding active residues and their distances between the docked residues of HSA and molecules of ligand 8CB are calculated by molecular docking. Temperature-dependent Raman spectroscopy is used to analyse the spectral behaviour of the interactions. The residues validated by molecular docking studies correlate well with the findings of Raman spectra for the interaction between 8CB and HSA.