Self-assembly of folic acid dextran conjugates for cancer chemotherapy.

Folic acid (FA) has long been used as a specific targeting agent since many cancer cells overexpress folate receptors (FRs). Herein, novel functionalities of FA will be explored: directed self-assembly of nanoparticles for drug delivery together with pH responsive release. By conjugating with dextran (DEX), DEX-FA exerts a pH dependent self-assembly behavior: it self-associates into nanoparticles (NPs) around physiological pH (pH 7) and disassembles at higher pH (pH > 9). Doxorubicin (DOX), a model antitumor drug, has been successfully encapsulated via electrostatic interactions between DOX and FA. Moreover, the pH responsive release behaviors of DOX are controlled by FA. The DOX@DEX-FA NPs exhibit typical FA-FRs-mediated endocytosis in vitro and targeted delivery in vivo, altogether contributing to an enhanced antitumor efficacy, alleviated side effects, and elongated overall survival in a 4T1 subcutaneous tumor-bearing mouse model. The DOX@DEX-FA NPs have been demonstrated to be a simple, safe and efficient nanoplatform, holding significant translation potential for treating FR-overexpressing cancers. This study may present novel functionalities of FA in cancer-targeted nanotherapeutics.