Bifunctional folic-conjugated aspartic-modified Fe3O4 nanocarriers for efficient targeted anticancer drug delivery

Functionalization of nanocarriers has been considered the most promising way of ensuring an accurate and targeted drug delivery system. This study reports the synthesis of bifunctional folic-conjugated aspartic-modified Fe3O4 nanocarriers with an excellent ability to deliver doxorubicin (DOX), an anticancer drug, into the intercellular matrix. Here, the presence of amine and carboxylate groups enables aspartic acid (AA) to be used as an efficient anchoring molecule for the conjugation of folic acid (FA) (EDC-NHS coupling) and DOX (electrostatic interaction). Based on the results, surface functionalization showed little effect on the physicochemical properties of the nanoparticles but significantly influenced both the loading and release efficiency of DOX. This is primarily caused by the steric hindrance effect due to large and bulky FA molecules. Furthermore, in vitro MTT assay of B16-F1 cell lines revealed that FA conjugation was responsible for a significant increase in the cytotoxicity of DOX-loaded nanocarriers, which was also found to be proportional to AA concentration. This high cytotoxicity resulted from an efficient cellular uptake induced by the over-expressed folate receptors and fast pH triggered DOX release inside the target cell. Here, the lowest IC50 value of DOX-loaded nanocarriers was achieved at 2.814 +/- 0.449 mu g mL(-1). Besides, further investigation also showed that the drug-loaded nanocarriers exhibited less or no toxicity against normal cells.

Automated summary

This study reports on the synthesis of bifunctional nanocarriers that can accurately and targetedly deliver an anticancer drug. The surface functionalization of the nanocarriers had little effect on their physicochemical properties but significantly influenced drug loading and release efficiency. The conjugation of folic acid led to increased cytotoxicity of the drug-loaded nanocarriers.