Silica not so inert after all

Powdered silica has long had a reputation for being chemically inert, nontoxic, and biocompatible. But that description may be inaccurate, according to a biomolecular study ( Proc. Natl. Acad. Sci. U.S.A. 2023, DOI: 10.1073/pnas.2304735120 ). Manufacturers in the food and healthcare industries use microscopic particles of silica (SiO 2 ) in various formulations. For example, the amorphous form of the material, which is approved for use by the US Food and Drug Administration, serves as an anticaking agent to prevent clumping in powdered foods, cosmetics, and skin care products. And the material is being studied for use in drug delivery and as a carrier of imaging agents. Despite its widespread use, silica may not be inert after all. Yangjie Li and Richard N. Zare of Stanford University, and Kurt W. Kolasinski of West Chester University found that adding commercial silica particles to aqueous solutions of L -cysteine, glutathione, and D