Chitosan-boronate polymer synthesis for cancer therapy application

Cancer is currently the second world leader in death and oxidative stress has been identified as one of the main causes of this disease[1]. Antioxidants such as polyphenols, quercetin[2] and mangiferin[3], have shown the ability to interfere in the redox signaling mechanisms, and the combination with conventional drugs, such as doxorubicin, may bring benefits to patients. However, antioxidants have low bioavailability and chemical instability. In addition, the conventional drugs are cytotoxic. So, the use of nanocarriers, such as polymeric nanoparticles (NPs) of chitosan[4], are recommended to achieve good drug efficacy. In this work, chitosan was modified with 4-formyl-phenylboronic acid to allow binding to polyphenols and to target the NPs to cancer cells. The chemical modification of chitosan was confirmed by 1H-NMR and infrared spectroscopy. The degree of chitosan deacetylation (96%), the degree of chitosan substitution by 4-FBPA (13%) and the critical aggregation concentration (CAC) of both polymers were also determined.