Near IR (NIR) sensitive Au-Au₂S nanoparticles were prepared by mixing HAuCl₄ and Na₂S in aqueous solutions. An anti-tumor drug, cis-platin, was adsorbed onto Au-Au₂S nanoparticle surface via the 11-mercaptoundecanoic acid layers. The results showed that the degree of adsorption of cis-platin onto Au-Au₂S nanoparticles was controlled by the pH value of solution, and the drug release was sensitive to NIR irradiation. The cis-platin loaded Au-Au₂S nanoparticles can be potentially applied as NIR activated drug delivery carrier. / Singapore-MIT Alliance (SMA)