Enhanced cellular uptake of folic acid-conjugated PLGA-PEG nanoparticles loaded with vincristine sulfate in human breast cancer

The aim of this paper is to evaluate the cellular uptake of vincristine sulfate-loaded poly(lactic-co-glycolic acid)-polyethylene glycol (PLGA-PEG) nanoparticles with the folic acid modification (PLGA-PEG-folate NPs). PLGA-PEG-folate NPs were prepared using a water-oil-water emulsion solvent evaporation method. The particle size, surface morphology, drug encapsulation efficiency, and the drug release behavior were investigated. The NPs exhibited a biphasic drug release with a moderate initial burst followed by a sustained release profile. Internalization of the NPs labeled with coumarin- 6 by MCF-7 (Michigan Cancer Foundation-7) human breast cancer cells was quantitatively measured by microplate reader, and qualitatively analyzed by fluorescent microscopy and confocal laser scanning microscopy. The results showed PLGA-PEG-folate NPs achieved significantly higher cellular uptake in the folic acid receptor overexpressed MCF-7 cells, compared to PLGA-mPEG NPs without the folic acid modification. Due to the enhanced cellular uptake, PLGA-PEG-folate NPs displayed the highest cytotoxicity. Judged by IC(50) after 24 h culture, the therapeutic effects of the drug formulated in the NPs with surface modification could be 1.52 times, 3.91 times higher than that of PLGA-mPEG NPs and free vincristine sulfate, respectively.