Transferrin-conjugated doxorubicin-loaded PLGA nanoparticles with pH-responsive behavior: a synergistic approach for cancer therapy

Doxorubicin (DOX) is an efficient chemotherapeutic agent widely used to treat different types of cancer; however, there is an inherent risk of adverse effects due to its unspecific action in healthy cells. In order to enhance the DOX arrival and accumulation inside the cancerous cells, we have developed DOX-loaded nanoparticles (NPs) using the biocompatible polymer poly(lactic-co-glycolic acid) (PLGA). pH sensitivity was achieved by incorporation of the surfactant, 77KS, while poloxamer was explored as stabilizer and chemosensitizer. The protein transferrin (Tf) was conjugated to the NPs with the role to actively targeting them to the cancerous cells. The nanoprecipitation method yielded NPs with size about 100 nm, with polydispersity index around 0.20 and a negative zeta potential. Transmission electron microscopy and infrared spectroscopy confirmed the shape and the functional groups presence. DOX release from the NPs followed a control and pH-sensitive pattern, allowing accelerated DOX release in acidic conditions. Through the hemolysis assay, using the erythrocyte as a model for the endosomal membrane, it was evidenced the pH-sensitive membranolytic behavior of the NPs. Furthermore, the NPs were safe and compatible with blood. Finally, the formulations were applied to tumor and non-tumor cell lines, HeLa and HaCaT, respectively. Over 72 h of incubation, the Tf-conjugated NPs induced a notable reduction in HeLa cell growth and were able to protect the HaCaT cells from the DOX unspecific cytotoxicity. The results suggest that the dual-active targeting promoted by 77KS and Tf is a promising platform to overcome the side effects of conventional chemotherapeutic drugs and nontargeted nanosystems.