Polyoxometalates (POMs) are a class of well-defined transition metal-oxide nanoclusters and have potential applications in material science such as catalysis, electrochemistry, materials science, and medicine.As important inorganic drug candidates, POMs have shown promising antiviral, antibacterial and antitumoral activities.However, no POM has been brought to market after the development of clinical trials.And the negatively charged and nano-sized properties of POMs can not facilitate their penetration into cells.