Chitosan nanogels as nanocarriers of polyoxometalates for breast cancer therapies

Polyoxometalates (POMs) have been revealed as interesting antitumor agents inhibiting the action of Sox2 transcription factor, which reduces the risk of metastasis during hormonal therapies. However, they have shown serious concerns to be incorporated into the cells due to their cytotoxicity. Taking this into consideration, this study aims to develop polyoxometalate-based nanocarriers to be potentially applied as new forms of anticancer therapies. Thus, the Wells-Dawson type [P2Mo18O62](6-) phosphomolybdate was physically loaded into covalently crosslinked chitosan nanogels that can act as nanocarriers for local delivery. The obtained nanocomposites were extensively characterized by P-31-NMR, TEM microscopy, DLS and zeta potential measurements. This work revealed that selected chitosan nanocarriers would present great potential for POM delivery into tumoral cells due to their pH-triggered deliverability that inhibits cytotoxic drug release at physiological pH. Furthermore, the high uptakes values reported herein make prepared nanocomposites interesting candidates for future breast antitumoral treatments.