Glucose Responsive Phenylboric Acid Grafted Chitosan Hydrochloride for Anti-tumor Drug Delivery

Phenylboronic acid grafted chitosan hydrochloride (HCSPBA) was synthesized by introducing phenylboronic groups to the polymer chain of chitosan hydrochloride through simple molecule modification by the reaction between the amine group of chitosan hydrochloride and the carboxyl group of 3-carboxyphenylboronic acid. The structure of the amphipathic compound was confirmed by FTIR and H-1-NMR, and the graft ratio of phenylboronic can be tuned by changing the feed ratio. The cytotoxicity of the HCSPBA was assessed using CCK-8 assay, and the result showed good cytocompatibility. Hydrophobic drugs can be encapsulated to the assembled polymeric micelles of HCSPBA, and showed sustained and controllable release. Herein, doxorubicin was selected as model drug, and the drug release behavior has good glucose responsibility. Without glucose, the cumulative release rate was very low at physiological pH =7. 4 and weak acidity (pH = 6. 5) condition of solid tumor, while the rate was accelerated when glucose was present in the medium, due to the swelling/disruption of the HCSPBA micelles as a result of the better hydrophilicity of the compound after the combination of phenylboronic group and glucose. Since the high glucose concentration physiological microenvironment of diabetes and solid tumor tissue, the HCSPBA has potential application in developing glucose responsive drug delivery systems, such as smart insulin and anti-tumor drug delivery systems.