Detectives may be able to obtain a clear set of fingerprints even on wet surfaces by using a powder made up of zinc oxide nanoparticles, Australian researchers are suggesting.

Dr Andrew McDonagh, an expert with the Centre for Forensic Science at the University of Technology, Sydney (UTS), says that traditional powder reveals fingerprints by sticking to the oily residues left on the surface, but this does not always work.

He points out that it often becomes hard for investigators to obtain fingerprints on wet surfaces such as sinks or bath tubs, especially when part of the print has been washed away.

McDonagh says that he and his colleagues worked in collaboration with the Australian Federal Police, and tested a new fingerprint powder based on zinc oxide nanoparticles on surfaces such as glass, polyethylene and aluminium.

According to him, the 20-nanometre zinc oxide particles clump together in one micrometre sized flower-like crystals, much smaller than the current 10 micrometre fingerprint powder particles.

He said that illuminating the nanoparticles with ultraviolet light caused them to fluoresce without the addition of any fluorescent dyes.

The research team observed that the zinc oxide nanoparticle powder gave a much clearer picture of the fingerprints, compared to conventional powders.

"When you dust with a powder, you're hoping that it will stick only to the fingerprint, but often it will stick to everything," ABC Online quoted McDonagh as saying.