243. Tuning Net Charge in Aliphatic Polycarbonates Alters Solubility and Protein Complexation Behavior

Nicholas D. Posey, Yuanchi Ma, Michael Lueckheide, Julia Danischewski, Jeffrey A. Fagan and Vivek M. Prabhu; ACS Omega; (2021); DOI: 10.1021/acsomega.1c02523 (open access)

A synthetic strategy yielded polyelectrolytes and polyampholytes with tunable net charge for complexation and protein binding. Organocatalytic ring-opening polymerizations yielded aliphatic polycarbonates that were functionalized with both carboxylate and ammonium side chains in a post-polymerization, radical-mediated thiol–ene reaction. Incorporating net charge into the polymer architecture altered the chain dimensions in phosphate buffered solution in a manner consistent with self-complexation and complexation behavior with model proteins. A net cationic polyampholyte with 5% of carboxylate side chains formed large clusters rather than small complexes with bovine serum albumin, while 50% carboxylate polyampholyte was insoluble. Overall, the aliphatic polycarbonates with varying net charge exhibited different macrophase solution behaviors when mixed with protein, where self-complexation appears to compete with protein binding and larger-scale complexation.