Durable Biomolecular Assemblies for Protein-Powered Device Concepts

Physically encapsulated droplet-interface bilayers are formed by confining aqueous droplets surrounded by lipid mono-layers in connected compartments within a solid substrate. The droplets reside within each compartment and are positioned on fixed electrodes built into the solid substrate. Full encapsulation of the network is achieved with a solid cap that inserts into the substrate to form a closed volume. Encapsulated networks provide increased portability over unencapsulated networks by limiting droplet movement and by integrating the electrodes into the supporting fixture. The formation of encapsulated droplet-interface bilayers is confirmed with electrical impedance spectroscopy and cyclic voltammetry is also used to measure the effect of alamethicin proteins incorporated into the resulting lipid bilayers. The durability of the networks is quantified using a mechanical shaker to oscillate the bilayer in a direction transverse to the plane of the membrane and the results show that single droplet-interface bilayers can withstand several g’s of acceleration. Observed failure modes include both droplet separation and bilayer rupturing, where the geometry of the supporting substrate and the presence of electrodes are key contributors. Physically encapsulated DIBs can be shaken, moved, and inverted without bilayer failure, enabling the creation of portable, protein-powered devices.