Formation of lipid bilayers on the pore walls of macroporous silicon

Electron paramagnetic resonance (EPR) spectroscopy was used to study the pore filling of macroporous silicon with lipid vesicles (liposomes), added with a spin label. Different EPR spectra were obtained with the magnetic field parallel and perpendicular to the macroporous silicon sample surface. These spectra could be well simulated with an admixture of the isotropic spectrum of liposomes, plus a simulated spectrum corresponding to a cylindrical distribution of lipid bilayers. This means that a portion of the liposomes were disrupted, and supported lipid bilayers were formed covering the inner surface of the pores. Diverse protocols can be explored in order to optimize the lipid covering of the pore walls, and to achieve an adequate lipid hydration. This system can be used as a platform to study lipid phase transitions in a confined environment, and to characterize membrane proteins.