Polyelectrolyte–protein nanocomplexes prepared under mild and simple conditions which could have biological activity arising from protein have emerged as fascinating protein delivery systems. However, common polyelectrolytes have problems of biocompatibility and metabolism in vivo, which may limit their further applications. Herein, a novel polyethylene glycol polyelectrolyte was synthesized and used for carrying protein drugs. Different from previously reported polyelectrolyte–protein nanoclusters, the polyethylene glycol polyelectrolyte–protein nanoclusters avoid organic solvent and protein modification, and the structure and bioactivity of proteins are well preserved. Moreover, the polyethylene glycol polyelectrolyte–protein nanoclusters have good hemocompatibility and biocompatibility. These novel polyethylene glycol polyelectrolyte–protein nanoclusters would provide a potent tool for fabrication of versatile protein drug carriers.
