C&EN talks with Xiaogang Liu, fluorescence expert

Abstract

Fluorescent dyes routinely light up cells and tissues under the microscope. And as microscopy techniques achieve higher resolutions, biologists will need dyes that glow more brightly and last longer. Xiaogang Liu leads a team at the Singapore University of Technology and Design that develops new and better fluorophores. But one personal project of Liu’s involves cataloging the natural fluorescence of products such as oils, honeys, and wines as a novel way to fight food fraud. By plotting the characteristic fluorescence of each product across a range of wavelengths, Liu and his students have built a small library of these fluorescence fingerprints. With these fingerprints, Liu hopes to identify adulterated food products or even gutter oil—illicit cooking oil made by recycling waste grease and fat. This counterfeit oil is sold to street-food vendors and restaurants in Asia, despite repeated crackdowns (Global Health Promot. 2016, DOI: 10.1177/1757975915623733). With prolonged heating and recycling