A cell specific peptide (Arg‐Gly‐Asp; RGD)‐modified nanogel was prepared and evaluated for its potential to act as a protein delivery carrier. A bovine serum albumin (BSA)/RGD‐modified nanogel complex was efficiently internalized into cells through integrin‐mediated endocytosis. Endosomal escape of the RGD‐modified nanogel was observed after 24 h incubation. The nanogel proved useful for targeted protein delivery.
A hyaluronic acid‐based anionic nanogel formed by self‐assembly of cholesteryl‐group‐bearing HA is designed for protein delivery. The HA nanogel spontaneously binds various types of proteins without denaturation, such as recombinant human growth hormone, erythropoietin, exendin‐4, and lysozyme. The HA nanogel shows unique colloidal properties, in particular that an injectable hydrogel is formed by salt‐induced association of the HA nanogel. A pharmacokinetic study in rats shows that an in situ gel formulation, prepared by simply mixing rhGH and HA nanogel in phosphate buffer, maintains plasma rhGH levels within a narrow range over one week. Therefore, HA nanogels offer a simple method for easy formulation of therapeutic proteins and are effective for sustained protein release systems.
