• 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.

Source: The Hindu