Nanoparticles comprising a fluorescent dye based on entrapment of a protein or DNA dye as agents for imaging finger prints

Discloses an agent for imaging latent fingerprints comprising nanoparticles, wherein said nanoparticles comprises an intrinsic fluorescent material or a fluorescent dye selected from a protein-dye conjugate and a DNA-dye conjugate, wherein said fluorescent material or fluorescent dye is entrapped within the nanoparticle and wherein said nanoparticles are derived from a sol gel. Particularly preferred embodiments utilise cadmium sulphide or cadmium selenide nanoparticles, Texas Red labelled gelatin, porcine thyroglobulin or flurorescein-labelled bovine serum albumin. Further disclosed are methods of detecting latent fingerprints comprising the use of said nanoparticles.