When a person has jaundice, the bilirubin gets deposited on the skin surface.
Gold nanoclusters that have been functionalised [using chitosan and mercaptopropionic acid] show yellow luminescence under UV light.
But when copper salt (copper sulphate) is added to it, the yellow luminescence gets quenched or reduced.
When bilirubin is added to the medium, the copper preferentially interacts with it, forming a complex and the luminescence of the gold nanoclusters gets restored.
This quick test has been developed by team of IIT Guwahati.
They just need a thumb imprint for detecting hyperbilirubinemia, a condition in which the amount of bilirubin in the blood is in excess and turns the sclera of the eye, urine and even the skin yellow.
Hyperbilirubinemia is commonly seen in people with jaundice and newborns. A person is said to have jaundice when the bilirubin concentration in the blood typically exceeds 12 ppm in adults and 50 ppm in a newborn.
While visual observation of yellow colour of the sclera and/or urine is routine for detecting jaundice, it is confirmed by a blood test. This new test is quicker.