Facile solution routes for the syntheses of water-dispersable germanium nanoparticles and their biological applications

A simple method for preparing water-dispersable multifunctional germanium nanoparticles (GeNPs) in chitosan (CS) colloid was reported, which met the growing interest of green chemistry. The monodisperse CS-GeNPs were synthesized through the formation of Ge-N bond with a mean particle size of 60 nm and were characterized by UV-visible absorption spectroscopy, FTIR, HR-TEM and XRD measurements. The size and dispersibility of CS-GeNPs were controlled through tuning the initial dosage of CS. To test its potential in biological applications, CS-GeNPs were functionally loaded with doxorubicin (Dox) drug and conjugated with folic acid (FA), the resulting Dox-loaded FA-CS-GeNPs were capable of effectively killing MCF-7 human cancer cells. Fluorescent images showed that Dox-loaded FA-CS-GeNPs targeted cancer cells through FA receptors-mediated pathway. Furthermore, GeNPs had high efficiency of photothermal conversion. This study showed a new type of multifunctional Ge nanoparticles to achieve synergetic effect between drug-targeted delivery and photothermal therapy.