Saliva test

A team of researchers at the University of California Los Angeles (UCLA) have developed an optical sensor that could be used to test saliva for diseases in the body.

The optical sensor can be integrated into a specially designed lab-on-a-chip, or microchip assay, and preprogrammed to bind a specific protein of interest, generating a sustained fluorescent signal as the molecules attach.

A microscope then reads the intensity of the fluorescent light - a measure of the protein’s cumulative concentration in the saliva sample - and scientists gauge whether it corresponds with levels linked to disease.

In their initial experiments, the researchers, led by UCLA's Dr Chih-Ming Ho, primed the optical protein sensor to detect the IL-8 protein, which at higher-than-normal concentration in saliva is linked to oral cancer.

Using saliva samples from 20 people – half healthy, the others diagnosed with oral cancer – the sensor correctly distinguished in all cases between health and disease.