Silver Nanoneedle Probes for Controlled, Long Term Single Channel Nanopore Sensing

Description:
Ion channel proteins showed great promise in the field of nanopore sensing and molecular flux imaging. In this talk, I will discuss silver nano probes that support sustained DC stable channel currents due to the AgCl layer formed around the tip during the fabrication process. This nano needle represents a promising probe material (Ag/AgCl) with an approach based on current feedback controlled tip-positioning to maintain long-term single-channel recordings up to 3 hours. We develop a hybrid positioning control system, where the channel current is used as feedback to control the vertical movement of the silver tip and subsequently, control the number of protein channels inserted in the lipid membrane. Our findings reveal that the area of lipid bilayer decreases with moving the silver tip up (i.e., decreasing the displacement in the z-direction). By reducing the bilayer area around the fine silver tip, we minimize the probability of multiple insertions and remove unwanted proteins. In addition, we characterize the effect of lipid properties such as fluidity on the lipid membrane area. We believe that the use of silver nanoneedle, which enables DC stable channel current, coupled with the developed tip displacement mechanism will offer more opportunities to employ these probes for chemical imaging and mapping different surfaces.

Speaker: Ryan White - University of Cincinnati