Preparation of folic acid-conjugated, doxorubicin-loaded, magnetic bovine serum albumin nanospheres and their antitumor effects in vitro and in vivo

Background: This study aimed to generate targeted folic acid-conjugated, doxorubicin-loaded, magnetic iron oxide bovine serum albumin nanospheres (FA-DOX-BSA MNPs) that lower the side effects and improve the therapeutic effect of antitumor drugs when combined with hyperthermia and targeting therapy. A new nanodrug using magnetic nanospheres for heating and addition of the folate receptor with cancer cell specificity was prepared. The characteristics of these nanospheres and their antitumor effects in nasopharyngeal carcinoma were explored. Methods: FA-DOX-BSA MNPs comprising encapsulated magnetic iron oxide nanoparticles were prepared using a desolvation cross-linking method. Activated folic acid (N-hydroxysuccinimide ester of folic acid) was conjugated to the surface of albumin nanospheres via amino groups. Results: Folic acid was successfully expressed on the surface of the nanospheres. Electron microscopy revealed that the FA-DOX-BSA MNPs were nearly spherical and uniform in size, with an average diameter of 180 nm. The nanomaterial could deliver doxorubicin at clinically relevant doses with an entrapment efficiency of 80%. An increasing temperature test revealed that incorporation of magnetic iron oxide into nanospheres could achieve a satisfactory heat treatment temperature at a significantly lower dose when placed in a high-frequency alternating magnetic field. FA-DOX-BSA MNPs showed greater inhibition of tumors than in the absence of folic acid in vitro and in vivo. Compared with chemotherapy alone, hyperthermia combined with chemotherapy was more effective against tumor cells. Conclusion: Folic acid-conjugated bovine serum albumin nanospheres composed of mixed doxorubicin and magnetic iron oxide cores can enable controlled and targeted delivery of anticancer drugs and may offer a promising alternative to targeted doxorubicin therapy for nasopharyngeal carcinoma.