Facile synthesis of multifunctional germanium nanoparticles as a carrier of quercetin to achieve enhanced biological activity.

A simple method for preparing quercetin surface-functionalized germanium nanoparticles (Qu-GeNPs) with enhanced antioxidant and anticancer activity is reported. Spherical germanium nanoparticles (GeNPs) were capped by quercetin (Qu) with a mean particle size of approximately 33 nm and were characterized by TEM, AFM, UV-visible absorption spectroscopy, FTIR, and XRD measurements. The in vitro drug release of Qu from the Qu-GeNPs indicated that Qu could principally be distributed around tumor tissues rather than in the normal section and Qu-GeNPs were internalized by MCF-7 cells. Their biological activity test results indicated that these Qu-GeNPs possessed stronger hydroxyl-scavenging effects and proliferative inhibition effect on MCF-7 cancer cells than quercetin, thus suggesting that the strategy to use GeNPs as a carrier of Qu could be an efficient way to achieve enhanced antioxidant and anticancer activity. In addition, Qu-GeNPs possessed a high apoptotic induction effect in cancer cells, especially in high dosages, and could arrest MCF-7 cells in the S phase.