Brighter nanoparticles could help detect drug impurities and pollutants

University of Toronto engineers developed tiny particles that glow green under near-infrared light after attaching to a target chemical. The particles can detect very small quantities and distinguish molecules made from the same atoms arranged in different ways, a difference that can affect a drug's safety or effectiveness. The researchers redesigned the particles in layers so incoming light energy moves inward rather than being lost. They reported a signal about 150 times brighter than particles without added dye and about 50 times brighter than some optimized earlier designs. The work remains a laboratory proof of concept. Manufacturing the particles at scale is still an obstacle to using them in drug-quality or pollution tests.