Spatial Organization of Biological Fuctions | BPS Thematic Meeting

Spatial Organization of Biological Functions Meeting

Poster Abstracts

17-POS Board 17 CHOLESTEROL MODULATED ASSEMBLY OF GRAPHENE OXIDE NANO-FLAKES AT A PHOSPHOLIPID INTERFACE Ajit Seth 1 ; Rajendra P. Giri 2 ; Nicholas Hayen 3 ; Prashant Hitaishi 3 ; Bridget M. Murphy 3 ; Sajal K. Ghosh 1 ; 1 Shiv Nadar Institution of Eminence, Physics, Gautam Buddha Nagar, India 2 Indian Institute of Technology Dhanbad, Physics, Dhanbad, India 3 Institut fur Experimentelle und Angewandte Physik, Christian-Albrechts-Universität Zu, Physics, Kiel, Germany Graphene oxide (GO) is being readily explored to develop novel devices for biophysical applications. To efficiently realize these applications of GO for humans, it is essential to understand the interaction of GO with cellular membranes. In the present study, differently charged phospholipid molecules with varying cholesterol concentrations are spread at the air water interface to mimic one of the leaflets of a cellular membrane. These molecules are further compressed to form a Langmuir monolayer with and without nano-flakes of GO dispersed in the subphase. Initially, the assembly of these flakes in and around the monolayer is quantified by surface pressure−area isotherms. The cholesterol molecules tend to make the monolayer compact and provide additional stability to the monolayer. Subsequently, the in-depth molecular details about the GO-cholesterol-lipid assembly are revealed by performing X-ray scattering measurements on these Langmuir monolayers using a liquid diffractometer. In the absence of cholesterol, GO being negatively charged, selectively affects the self-assembly of the positively charged phospholipid molecules, and the interaction is essentially governed by electrostatics. However, when cholesterol is present in the lipid monolayer, an additional affinity of GO towards the lipid molecules is observed, irrespective of the electrostatic nature of the lipid molecules, leading to the penetration of the monolayers. These cholesterol-induced increased affinities of GO nanoflakes towards phospholipid molecules can help design cationic lipid-based carriers for advanced drug delivery applications.

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