Multifunctional PLGA microfibrous rings enable MR imaging-guided tumor chemotherapy and metastasis inhibition through prevention of circulating tumor cell shedding

Simultaneous inhibition of tumors and tumor metastasis can be considered as an ideal and ultimate goal for cancer therapy. We report a unique platform based on DNA aptamer-functionalized microfibrous rings for simultaneous inhibition of primary tumors and tumor metastasis. Doxorubicin-loaded electrospun poly(lactic-co-glycolic acid) fibrous mat was prepared and homogenized in the presence of salt to form microfibrous rings that were functionalized with gadolinium chelates and DNA aptamer via polyethyleneimine-mediated conjugation. The multifunctional fibrous rings have an average diameter of 11.1 µm, and exhibit good biocompatibility, pH-dependent long-term drug release profile, and a high r1 relaxivity. Due to the ring structure and the DNA aptamer functionalization, the multifunctional fibrous rings are able to target and anchor tumor cells for a relatively long retention time as verified by magnetic resonance imaging, consequently decreasing the tumor cell shedding into the blood to form circulating tumor cells and inhibiting tumor metastasis and invasion.