Photothermally-Assisted Lipid Bilayer Coating on a Sin Nanopore for High-Throughput Protein Channel Formation

Abstract

In our recent study, we found that irradiation of a visible laser beam on a silicon nitride (SiN) membrane results in localized heating, which allows control over the temperature at a nanopore sensor with μs-scale kinetics. Here we demonstrate the formation of a planar lipid bilayer coating on a SiN pore using a photothermal heat shock. We first demonstrate that 100-nm-diameter liposomes composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) can be electroosmotically driven to a SiN aperture by showing their translocation through a 300 nm diameter pore. We then use this electroosmotic flow to reversibly trap/dock liposomes at the entrance of a 50 nm pore under applied voltage, as evidenced by a reduced ion current through the pore. Once a liposome is trapped, we use a laser pulse to rapidly heat the SiN pore, which causes a thermal shock that ruptures the liposome, forming a planar lipid bilayer with low leakage. We demonstrate that the resulting ruptured vesicle is a bilayer by testing its voltage stability, as well as by demonstrating DNA translocations through a a-hemolysin loaded liposome that was ruptured on the SiN aperture. Our lipid coating using SiN photothermal heating aids high throughput and highly stable lipid bilayers for studies of single-molecule transport and sensing.