Folate-conjugated, mesoporous silica functionalized boron nitride nanospheres for targeted delivery of doxorubicin.

Biomedical application of boron nitride (BN) nanomaterials has recently attracted considerable attentions. BN nanospheres (BNNS) could safely deliver anti-cancer drug into tumor cells, which makes them potential nanocarrier for cancer therapy. However, the poor dispersity in physiological environments and low drug loading capacity severely limit their further applications. Herein, we developed a novel drug delivery system based on folate-conjugated mesoporous silica (MS)-functionalized BNNS (BNMS-FA). Dispersity and drug loading capacity of BNNS were highly improved by MS modification. BNMS-FA complexes were nontoxic up to a concentration of 100 μg/mL, and could be specifically internalized by HeLa and MCF-7 cells via folate receptor-mediated endocytosis. Doxorubicin (DOX) could be loaded onto BNMS-FA complexes with high efficiency via π-π stacking and hydrogen bonding, and showed a sustained release pattern under different pH conditions. BNMS-FA/DOX complexes exhibited superior drug internalization and antitumor efficacy over free DOX, BNNS/DOX and BNMS/DOX complexes, which were considered promising for targeted cancer therapy.