Smart composites based on ferromagnetic hybrid aerogels have been prepared. These novel materials change chemistry in response to light to form nanoparticles that react with compounds that are present in the environment of the aerogels. Thus, high surface area silica/functional polymer hybrid aerogels have been formed via sol-gel synthesis. They also can contain coordinated metal-ion species. They are reacted with Fe-precursors to form air stable ferromagnetic aerogels, which they are transformed into active particles themselves or by incorporation of additional metal ions. These active materials, which adhere to tissue, can be positioned magnetically within their environment. Once they are positioned, they can be transformed by UV light to form Au(0) nanoparticles which react with the molecules in their environment. The preparation and properties of these aerogels, their photochemistry and reaction with bio-molecules will be presented.