Poly(lactic-co-glycolic acid) encapsulated platinum nanoparticles for cancer treatment

Metal nanoparticles have been of interest to the field of nanomedicine due to their potential for cancer treatment, diagnosis, and antimicrobial activity. Particularly, platinum nanoparticles (PtNPs) have been reported to have remarkable anticancer effects and low toxicity in healthy cells. In this paper, we propose a delivery system for PtNPs as a substitute for common chemotherapy treatment. The anticancer effect of PtNPs was tested against triple negative breast cancer (TNBC) showing no cell viability for most of the concentrations used, while not being toxic against fibroblasts. To improve accumulation at the tumor site, a delivery system based on poly(lactic-co-glycolic acid) (PLGA) particles was used. Encapsulation was achieved by nanoemulsion, resulting in 59% PLGA particles containing PtNPs, and 12.5% PtNPs by weight. To improve the circulation time and specificity of the system, the PLGA particle surface was modified. Passive targeting with poly(ethylene glycol) (PEG) and active targeting with an antibody (anti-EGFR) were used, obtaining two different sets of particles, Pt-PLGA-PEG and Pt-PLGA-PEG-EGFR. To evaluate both sets of particles, cell studies were carried out against TNBC. Cell experiments demonstrated that Pt-PLGA-PEG-EGFR particles were more effective as a cancer treatment than Pt-PLGA-PEG particles, however, free PtNPs were more effective than the encapsulated PtNPs. This was likely due to the time needed for PtNPs to release from PLGA, however, the amount of Pt internalized in the cells was greater with the Pt-PLGA-PEG-EGFR particles. These results suggest that the Pt NPs encapsulated in PLGA modified with a combination of PEG and EGFR targeting will provide the most effective therapy for future in vivo experiments. In summary, this study lays the groundwork for future cancer treatments based on PtNPs delivered with targeted PLGA particles.