Soft Materials Seminar - "Synthesis and Characterization of Polymer–Lipid Hybrid Membranes for Mimicking Neuronal Signaling through Switchable Ion Transport and Synaptic Plasticity"

Biological membranes play a central role in neuronal signaling by providing selective barriers and organizing proteins that regulate ion transport. Inspired by synaptic function, our research aims to develop polymer–lipid hybrid membranes that enable controlled and switchable ion transport using stimuli-responsive molecular organization. Our system combines a polypeptide as the protein-inspired functional component for mimicking ion channels and poly(N-isopropylacrylamide) (PNIPAM), a temperature-responsive polymer that can drive membrane reorganization through its lower critical solution temperature behavior, to form a polymer–peptide amphiphile (PPA). The PPA is then hybridized with dioleoylphosphatidylcholine (DOPC), which provides the lipid membrane environment for molecular organization. Building on a previously developed system containing a neutral polypeptide, we are introducing a glutamate-based, negatively charged polypeptide to promote electrostatic interactions with cations and potentially facilitate ion transport, thereby mimicking the ion-transport functionality involved in neuronal signaling. We synthesize the glutamate-based polypeptide through an N-carboxyanhydride (NCA) route and characterize the resulting precursors and polypeptide using nuclear magnetic resonance spectroscopy (NMR) and Fourier-transform infrared spectroscopy (FTIR). Current work focuses on optimizing NCA synthesis and purification to improve polypeptide yield and reproducibility. Ultimately, we aim to determine how charge and temperature-induced membrane organization influence polypeptide assembly and whether this organization can enable reversible ON/OFF control of ion transport.