Proposed biosensor for the detection of Bovine Serum Albumin using 7CB liquid crystals: A preliminary study

Liquid crystal (LC) based biosensors offer a sensitive platform for detecting biomolecules due to their ability to respond to molecular interactions through changes in LC orientations. In this paper, we introduce a novel LC biosensor using 4-heptyl-4-biphenyl carbonitrile (7CB) to detect Bovine Serum Albumin (BSA). The interaction between BSA and 7CB was investigated using polarising optical microscopy (POM), molecular docking (MD), and Raman spectroscopy. Time, temperature, and concentration-dependent POM experiments revealed that 7CB-BSA interaction induced a change in the LC texture producing bipolar and radial textures, with the biosensor demonstrating high selectivity for BSA at concentrations as low as 25 μM. A strong linear response to BSA concentration was observed, with a coefficient of determination (R² = 0.97973), indicating the biosensor's quantitative capabilities. Molecular docking analysis showed that 7CB binds to BSA with a minimal binding energy of -6.06 kcal/mol, supporting the strong interaction between the two. Raman spectroscopy revealed that specific amino acid residues, such as Phenylalanine (Phe) and Leucine (Leu) in BSA, significantly influence the symmetric and asymmetric stretching of the CH chains in 7CB leading shift in peak position (PP), line width (LW) and integrated intensity (II). The sensitivity, specificity, and label-free detection capability of this biosensor underscore its potential to enhance the performance of LC-based biosensing systems for protein detection.