Langmuir, Vol.26, No.12, 9835-9841, 2010
Selective Tethering of Ligands and Proteins to a Microfluidically Patterned Electroactive Fluid Lipid Bilayer Array
We report a new, quantitative methodology to pattern and present ligands from planar, supported, fluid lipid bilayers. By combining microfluidic lithography (mu FL) with an electroactive, chemoselective interfacial reaction strategy, a number of ligands as well as protein Concanavalin A were immobilized in lipid microarrays. Electroactive vesicles were generated after the spontaneous insertion of hydroquinone-tethered alkane (H(2)Q) into egg palmitoyloleoyl phosphatidylcholine (egg-POPC), followed by subsequent fusion to a siloxane-terminated self-assembled monolayer (SAM) on gold. An advantage of the H(2)Q system is that it can be electrochemically oxidized to the corresponding quinone (Q), followed by rapid chemoselective conjugation with oxyamine-functionalized (RONH2) ligands. The oxime product is also electroactive, and the reaction can be monitored and the amount of ligand bound can be quantified by electrochemistry. The bilayers were characterized by electrochemistry, fluorescence microscopy, and ellipsometry and were determined to be fluid by fluorescence recovery after photobleaching (FRAP). This strategy provides a synergistic method to pattern and present a number of ligands or biomolecules from the bilayer surface for the evaluation of enzyme or protein binding to biomembranes.