An active material, suitable for implantable medical devices. The active material is a mixture, composite, or aggregate of upconverting particles and photocatalytic particles embedded in an at least infrared light conducting and gas permeable support material. The upconverting particles convert longer wavelength light into shorter wavelength light, which in turn powers the photocatalytic materials to produce cytotoxic chemicals. When embedded into an implantable medical device in a desired body location, and exposed to red or infrared light, this active material can produce cytotoxic chemicals that in turn exert a cytotoxic effect on unwanted cells, such as cancer or microbial cells, as well as perform other functions.
