Diimide-enhanced fingerprint detection with photoluminescent CdS/dendrimernanocomposites

The chemical development of latent fingerprints by nanocomposites that invo lve photoluminescent cadmium sulfide nanoparticle aggregates with Starburst (R) dendrimer is demonstrated. The dendrimer bonds to fingerprint residue v ia its terminal functional groups. When these are amino groups (generation 4 dendrimer), the binding is enhanced by fingerprint pre-treatment with dii mide. The diimide converts carboxylic acid moieties of the fingerprint resi due to eaters that then react with the dendrimer amino groups to form amide linkages. The cadmium sulfide/generation 4 dendrimer development of finger prints is enhanced by elevated temperature also. Finally, fingerprint devel opment with carboxylate-functionalized cadmium sulfide/generation 3.5 dendr imer nanocomposites is examined. Here, diimide treatment of the dendrimer i tself aids the subsequent fingerprint labeling, which involves amino acid o f the figerprint residue. Nanocomposite fingerprint detection is compatible with time-resolved imaging for background fluorescence elimination.