Facile Formation of Polymer Supported Lipid Bilayers Using Deacetylated Chitin

Supported lipid bilayers (SLBs) are widely utilized as cellular membrane mimics. However, common membrane components, including membrane-external protein protrusions, are affected by the limited space available (~ 1 nm) between the surface-proximal bilayer leaflet and the underlying surface. This confinement can reduce membrane activity and hinder SLB applications. To provide additional space between the membrane and the supporting surface, which is typically glass, strategies involving thin polymer flims have been developed. Though effective, polymer cushioned SLBs often come with drawbacks including time-intensive preparation protocols and instabilities. Here we show that an air-stable polymer cushion product (Chitozen) based on the polysaccharide chitosan adhered to a microscope coverslip, is a viable surface for forming > 20 nm tall cushioned SLBs without any end user treatment. Bilayer deposition was achieved via straight forward incubation with small unilamellar vesicles and confirmed via fluorescence and atomic force microscopy. Two common lipids were employed, a pure zwitterionic lipid (POPC) and a zwitterionic/anionic lipid mixture ( E. coli Extract Polar). Both lipid species readily spread with area coverages similar to those achieved on clean glass surfaces without polymer cushions. Chitozen thus provides a straight-forward route to construct polymer supported lipid bilayers for a variety of biochemical and biophysical applications.