Soft, biologically inspired materials for neuromorphic memristors and memcapacitors

This talk will describe the development and characterization of neuromorphic elements for brain-inspired computing such as memristors and memcapacitors assembled from soft materials like lipids, polymers, peptides, proteins, and redox-active molecules. These materials do not function like true biological synapses, but they do exhibit highly nonlinear dynamical properties reminiscent of action potential propagation in neural networks in the central nervous system and use very similar sets of dynamical equations. Currently, the fragility and short lifetimes of soft-matter-based membranes such as lipid bilayers limit the assembly of individual biomolecular memristors or memcapacitors into extended biomembrane-based neuromorphic networks capable of brain-like sensing or computation. We use the droplet interface bilayer (DIB) platform to assemble and electrochemically characterize model bilayer membranes consisting of either amphiphilic polymer or lipid molecules that exhibit complex, nonlinear behaviors such as those found in biology, but that are also stable enough to be configurable into massively parallel neuromorphic circuits. These efforts are informed by vibrational sum-frequency generation spectroscopy, small-angle neutron scattering, fluorescence microscopy, and molecular dynamics simulations at both air-liquid and liquid-liquid interfaces. These experiments reveal previously hidden yet critically important structural and dynamical interactions occurring in both the headgroup region and in the hydrophobic tails that impact not only the memristive and memcapacitive behaviors but also membrane stability.