Manipulation of the Orientational Response of Liquid Crystals to Proteins Specifically Bound to Covalently Immobilized and Mechanically Sheared Films of Functionalized Bovine Serum Albumin

Abstract

This paper reports on the orientational behavior of thermotropic liquid crystals supported on films of biotinylated bovine serum albumin (BSA) that are covalently immobilized on the surface of glass substrates using (3-aminopropyl)triethoxysilane (APES) and disuccinimidyl suberate (DSS). The films of biotinylated BSA are mechanically sheared and then immersed into aqueous solutions of anti-biotin immunoglobulin G (IgG) prior to contact with nematic phases of 4-cyano-4′-pentylbiphenyl (5CB). Using ellipsometry, we found the capacity of the films of biotinylated BSA to bind anti-biotin IgG to be unchanged upon shearing with a polyester cloth. In contrast, we determined the orientational response of nematic phases of 5CB to the presence of bound anti-biotin IgG to be a strong function of the normal pressure applied during shearing, as well as the magnitude of the lateral displacement of the film of biotinylated BSA when in contact with the surface of the polyester cloth. The shear rate, however, appears to have little influence on the response of the liquid crystal to bound IgG. These results demonstrate that it is possible to manipulate the response (sensitivity) of liquid crystals to IgG specifically bound to sheared films of functionalized BSA by changing the manner of shearing of the films of BSA without changing the capacity of the films to bind IgG. We also report a characterization of the nanometer-scale topography of mechanically sheared films of biotinylated BSA using atomic force microscopy (AFM).

Optically Responsive and Mechanically Tunable Colloid‐In‐Liquid Crystal Gels that Support Growth of Fibroblasts

“…[2][3][4][12][13][14][15] Examples of recent progress include the use of LCs to report the presence of viruses captured at surfaces, [12] amplify receptor-ligand binding events involving proteins, [2] and report enzymatic activity. [3,13] Additionally, several studies have explored LCs as materials to create interfaces to mammalian cells. [4,15] Fang et al demonstrated that the thermotropic LC, 4-cyano-4 0 -pentylbiphenyl (5CB) assumed distinct orientations when it was layered over several different cell lines cultured on glass substrates.…”

“…The observation that several micrometersized LC domains of the CLC were covered by each fibroblast cell suggests that it may be possible to exploit the reordering of the LCs within those domains to report biomolecular and/or mechanical interactions with the LC. Past studies have demonstrated that subtle interactions of LCs with proteins, [2,13] lipids, [3] or surfactants [26] can induce changes in the orientational order of the LCs. To determine if interfacial interactions can dictate the ordering of LCs within the LC-rich domains of CLC gels, we confined the CLCs between chemically functionalized glass microscope slides that give rise to known orientations of the LCs.…”

Detecting and differentiatingEscherichia colistrain TOP10 using optical textures of liquid crystals

“…The advantages of LC biosensors include high sensitivity, low cost, ease of use and their labelfree nature. Recent studies have shown that LCs can transduce and amplify the presence of proteins, phospholipids, DNA, cells and viruses into optical readouts visible to the naked eye [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”

Self assembled monolayer based liquid crystal biosensor for free cholesterol detection

“…10,[12][13][14][15] These important characteristics of LC based biosensors make them well suited for simple detection, direct transduction, high sensitivity, and low-cost bioassays. [16][17][18][19] For the detection of enzymatic events, few LC biosensors have been reported because most of the enzymatic reactions catalyze substrate to generate some small-molecule products, whose disruption behaviour to the orientation of LC molecules is far smaller than that of macro-biomolecules. 13,[20][21][22] Recently, Liao and co-workers developed a LC biosensing system based on the enzymatic growth of gold nanoparticles (Au NPs) for the detection of acetylcholine (ACh) and acetylcholinesterase (AChE) inhibitor.…”