TETHERED LIPID BILAYERS WITHIN POROUS SILICON NANOSTRUCTURES: A PLATFORM FOR REAL-TIME MONITORING OF MEMBRANE-ASSOCIATED PROCESSES

The importance of understanding the physical properties of cell membranes in biological systems has prompted the development of artificial lipid bilayers, which can mimic the cellular membrane structure. Supported lipid bilayers (SLBs) have emerged as a promising avenue for studying basic membrane processes and for possible biotechnological applications, as they retain the lipid membrane fluidity and exhibit high mechanical stability. Conventional methods for SLB formation involve the spreading of lipid vesicles on hydrophilic solid supports. Herein, a facile approach for the formation of a supported and tethered lipid bilayer within an oxidized porous Si (PSiO₂) nanostructure, avoiding liposome preparation, is presented. We employ a two-step lipid self-assembly process, in which a first lipid layer is tethered to the pore walls resulting in a highly stable monolayer. A subsequent solvent exchange step induces the self-assembly of the unbound lipids into a robust SLB. Formation of PSiO₂-SLB is confirmed by fluorescence resonance energy transfer (FRET) and the properties of the confined SLB are characterized by environment-sensitive fluorophores. The unique optical properties of the PSiO₂ support are employed to monitor in real time the partitioning of a model amphiphilic molecule within the SLB via reflective interferometric Fourier transform spectroscopy (RIFTS) method. Our preliminary results demonstrate the potential of the developed system as a convenient tool for studying membrane-level processes.