Background: Cisplatin is a potent anticancer drug, but its clinical application has been limited due to its undesirable physicochemical characteristics and severe side effects. Better drug formulations for cisplatin are highly desired. Methodology/Principal Findings: Herein, we have developed a nanoparticle formulation for cisplatin with high encapsulation efficiency and reduced toxicity by using cisplatin-crosslinked carboxymethyl cellulose (CMC) core nanoparticles made from poly(lactide-co-glycolide)-monomethoxy-poly(polyethylene glycol) copolymers (PLGA-mPEG). The nanoparticles have an average diameter of approximately 80 nm measured by transmission electron microscope (TEM). The encapsulation efficiency of cisplatin in the nanoparticles is up to 72%. Meanwhile, we have also observed a controlled release of cisplatin in a sustained manner and dose-dependent treatment efficacy of cisplatin-loaded nanoparticles against IGROV1-CP cells. Moreover, the median lethal dose (LD 50) of the cisplatin-loaded nanoparticles was more than 100 mg/kg by intravenous administration, which was much higher than that of free cisplatin. Conclusion: This developed cisplatin-loaded nanoparticle is a promising formulation for the delivery of cisplatin, which wil
