Synthesis and testing of polymer grafted mesoporous silica as glucose-responsive insulin release drug delivery systems

Abstract

Stimuli-responsive materials based on mesoporous silica have been widely studied for the controlled release of drugs. Glucose-responsive systems play a vital role in the controlled release of insulin because they can smartly adjust the amount of released insulin in response to the fluctuational blood glucose concentration. Here, the mesoporous silica (MS) was modified with 3-fluoro-4-carboxyphenylboronic acid (FCPBA) to prepare phenylboronic acid-modified mesoporous silica (MS-FCPBA). N-acryloyl glucosamine (AGA) was copolymerized with N-isopropyl acrylamide (NIPAM) and acrylic acid (AAc) respectively to synthesize two polymers with diol groups, noted as P(NIPAM-co-AGA) and P(AAc-co-AGA) respectively. Since the phenylboronic acid group can form a borate ester bond with the diol group, the polymers were coated on the surface of insulin-loaded MS-FCPBA to obtain the insulin release systems. The results showed that the loading capacity and encapsulation efficiency of insulin could reach 14.7% and 85.9%, respectively. The two systems exhibited different glucose-responsive performance.