Understanding the Effect of Stereochemistry on Peptide-based Polyelectrolyte Complexation

Polyelectrolyte complexes are formed via electrostatically-driven complexation between oppositely charged polymers leading to phase separation into polymer-rich and polymer-sparse phases. Such soft materials are often used for drug delivery, coatings, and recyclable plastics. In vivo applications of polyelectrolyte complexation, however, face significant challenges as neither salt nor polymer concentration can be modulated inside the body. As a result, there is a need for alternative methods to control the structure and dynamics of complexes such as chain packing, diffusion, and rheology. Chirality offers a tunable design variable for controlling material properties by augmenting electrostatic complexation with stereocomplexation, i.e. stereospecific interactions between L- and D-enantiomers. In this talk, we will present our recent efforts in using all-atom molecular dynamics simulations to determine the enthalpic and entropic driving forces of polyelectrolyte complexation as a function of chirality for complexes containing poly(glutamic acid) and poly(lysine). Overall, our simulations demonstrate that subtle changes in solution conditions, chirality, and polyelectrolyte charge density significantly impact the chain conformations and dynamics of polyelectrolyte complexes.