Design and Testing of a Hydrogel-Based Droplet Interface Lipid Bilayer Array System

The research presented in this thesis includes the development of designs, materials, and fabrication processes and the results of characterization experiments for a meso-scale hydrogel-based lipid bilayer array system. Two design concepts are investigated as methods for forming Droplet Interface Bilayer (DIB) arrays. Both concepts use a base of patterned silver with Ag/AgCl electrodes patterned onto a flat polymer substrate. In one technique, photopolymerizable hydrogel is cured through a mask to form an array of individual hydrogels on top of the patterned electrodes. The other technique introduces a second type of polymer substrate that physically supports an array of hydrogels using a set of microchannels. This second substrate is fitted onto the first to contact the hydrogels to the electrodes. The hydrogels are used to support and shape droplets of water containing phospholipids, which self-assemble at the surface of the droplet when submerged in oil. Two opposing substrates can then be pushed together, and a bilayer will form at the point where each pair of monolayers come into contact.

The photopatterning technique is used to produce small arrays of hydrogels on top of a simple electrode pattern. Systems utilizing the microchannel substrate are used to create mesoscale hydrogel arrays of up to 3x3 that maintained a low resistance (~50-150 kΩ) connection to the substrate. Up to three bilayers are formed simultaneously and verified through visual observation and by recording the current response behavior. Arrays of varying sizes and dimensions and with different electrode patterns can be produced quickly and inexpensively using basic laboratory techniques. The designs and fabrication processes for both types of arrays are created with an eye toward future development of similar systems at the microscale.