Stabilization of polyoxometalates on gold nanoparticles surface using amino acid linker to control their toxicity

Polyoxometalates (POMs) have been used for antibacterial, antiviral and anticancer applications in in-vitro toxicological studies. These POMs induce oxidative stress at the cell surface and in the cytoplasm. However their instability at physiological pH, non specific binding, and high toxicity limits their direct application in biology and medicine. To circumvent that, we have developed a strategy to anchor them on a biocompatible carrier such as gold nanoparticles (AuNPs) by using an amino acid linker to regulate their stability and toxicity. AuNPs were synthesized by the reduction of gold ions using aspartic acid as reducing agent. These AuNPs were surface functionalized with cationic amino acid lysine to strongly anchor POMs. Subsequently, these lysine functionalized gold nanoparticles (AuNPsLys) were further modified with two POMs such as phosphotungstic acid (PTA) or phosphomolybdic acid (PMA). UV-visible, RAMAN, XPS, DLS and TEM studies were carried out to characterize these nanomaterials. Currently, we are exploring antibacterial, anticancer and other biological applications of these functionalized nanomaterials.