Investigation of Biophysical and Nano mechanical Properties of Single and Multicomponent supported lipid bilayers

Abstract

The biological membranes play a crucial role in the various biological processes due to their characteristic biophysical and nano-mechanical properties. The parame ters such as membrane composition, thickness undulations, and the influence of exter nal stimuli play a crucial role in the phase state behavior of biological membranes. The supported lipid bilayer (SLBs) systems closely represent cell membranes and are often studied to understand their behavior in response to various external stimulus such as temperature, cholesterol addition, mechanical stress etc. In this thesis, we have pre sented different experiments performed on single and multicomponent SLBs. In the first study, we implemented Spectroscopic Ellipsometry (SE)technique to explore the optical properties of various single-component lipid bilayers having different phase states (fluid and gel) under hydrated or native conditions. The measurement of ellip sometric angles and#936; and and#8710; were obtained from SE and were utilized to realize an explicit phase state dependence. Further, we obtained the thickness (t) and refractive index (n) by modeling these SE results. These results were found to be interrelated to the phase state and lateral organization. The bilayer thickness is further verified against values obtained from Coarse-Grained (CG) Molecular Dynamics (MD) simulations. The pro posed method was tested on various lipid bilayers under their native phase state at room temperature and was found to correlate with AFM measurements newline newline newline