Test shows diseases without microscope

PARIS - Agence France-Presse

Scientists in Britain say they have developed a super-sensitive test using nano-particles to spot markers for cancer or the AIDS virus in human blood serum using the naked eye.

As it does not need sophisticated equipment, the test-tube technique should be cheap and simple, making it a boon for disease detection in poor countries, the team wrote in Nature Nanotechnology on Oct. 28.

Researchers used the technology to scan for molecules of p24, a marker for HIV infection, and Prostate Specific Antigen or PSA, an early indicator of prostate cancer. Their method is used to analyze serum, a light-yellow fluid that is extracted from blood by a centifuge and is commonly used in health tests.

“If the result is positive for p24 or PSA, there is a reaction that generates irregular clumps of nanoparticles, which give off a distinctive blue hue in a solution inside the container,” said a statement. The reaction, in response to the presence of antibodies, occurred even at ultra-low concentrations of p24 or PSA.

“If the results are negative, the nanoparticles separate into ball-like shapes, creating a reddish hue. Both reactions can be easily seen by the naked eye.”