(351f) Design Rules for Biomacromolecule Encapsulation: Building Blocks for Biomedical Applications

Keeping therapeutics refrigerated accounts for approximately 80% of the cost and logistics of vaccines, with nearly half of all vaccines lost due to breaks in the cold chain. Relief programs, thus, struggle to maintain vaccine viability. To mitigate the reliance on the cold chain, vaccines and other temperature-dependent therapeutics need to be stabilized against higher temperatures. To combat this, methods for decreasing the reliance of these cargos on the cold chain have garnered attention, with many efforts focusing on encapsulation strategies. Our work focuses on complex coacervation as a purely aqueous encapsulation strategy. Complex coacervation is a liquid-liquid phase separation phenomenon dominated by electrostatic interactions and entropy. We investigated the use of a two-polymer coacervate system for protein encapsulation to facilitate the incorporation of weakly-charged protein cargo and explored the incorporation of three model proteins as a function of solution conditions, polymer properties, and distribution of charges on the proteins. We determined that the net charge and distribution of charges on both the protein and polymers dominated protein incorporation. Our results bring insights into drug delivery formulation, particularly with complex coacervates. Furthermore, we explored the feasibility of incorporating these biomacromolecules into fiber mats as a step toward active bandages.