Surface engineering for biomolecular analysis using liquid crystals

The research described in this thesis was designed to establish a simple yet quantitative analytical tool based on ordering transitions of liquid crystals (LCs) that can be used to report a broad range of interfacial phenomena, including the presence of specifically captured proteins on surfaces. The investigations described within are organized into three parts.;The first part of this thesis describes the engineering of poly(dimethylsiloxane) (PDMS) surfaces for the specific capture and transfer of the human epidermal growth factor receptor (EGFR). By taking advantage of 32P-radiolabeling of the autophosphorylation domain of the EGFR, we quantitatively investigate the efficiency of capture and subsequent transfer of the EGFR to a gold surface that has been chemically functionalized using self-assembled monolayers (SAMs).;The second part of this thesis describes an automated analysis technique for spatially mapping the orientation of twisted nematic liquid crystals (TNLCs) with micrometer resolution over millimeter-sized surfaces. Using this technique, we measure the response of TNLCs to the co-adsorption of mixed SAMs, the displacement of one SAM by another and the change in liquid crystal orientation in the presence of surface-bound proteins.;The final part of this thesis details the use of a simple model to identify a range of optimal conditions that will maximize the sensitivity of TNLCs to the presence of surface-bound proteins. We describe results that show how these optimal conditions can be realized in a precise and controllable manner through facile routes that involve the control of the nanoscale structure and/or chemical composition of the detection surface. We demonstrate that the sensitivity of the TNLC increases, as predicted by the model, through the use of affinity contact printing (alphaCP) of EGFR onto the optimized detection surface. Combined with the high spatial resolution of LC-based analysis, this work has the potential to enable measurements of single cell quantities of EGFR.;The results of the research described in this thesis, when taken together, form the basis for quantitative liquid crystal-based analytical techniques for the detection of small quantities of clinically relevant biomolecules.