Stable, ligand-doped, poly(bis-SorbPC) lipid bilayer arrays for protein binding and detection

A continuous-flow microspotter was used to generate planar arrays of stabilized bilayers composed of the polymerizable lipid bis-SorbPC and dopant lipids bearing ligands for proteins. Fluorescence microscopy was used to determine the uniformity of the bilayers and to detect protein binding. After UV-initiated polymerization, poly(lipid) bilayer microarrays were air-stable. Cholera toxin subunit b (CTb) bound to an array of poly(lipid) bilayers doped with GM₁, and the extent of binding was correlated to the mole percentage of GM₁ in each spot. A poly(lipid) bilayer array composed of spots doped with GM₁ and spots doped with biotin-DOPE specifically bound CTb and streptavidin to the respective spots from a dissolved mixture of the two proteins. Poly(bis-SorbPC)/GM₁ arrays retained specific CTb binding capacity after multiple regenerations with a protein denaturing solution and also after exposure to air. In addition, these arrays are stable in vacuum, which allows the use of MALDI-TOF mass spectrometry to detect specifically bound CTb. This work demonstrates the considerable potential of poly(lipid) bilayer arrays for high-throughput binding assays and lipidomics studies.