This document specifies a method for the measurement of the photocatalytic activity (PCA) of
nanoparticles (NPs), suspended in an aqueous environment in physiologically relevant conditions, by
measuring the ultraviolet (UV)-induced nicotine adenine dinucleotide hydrate (NADH) oxidation.
The measurement is intended to assess the potential for the photo-toxicity of nanomaterials. The
method is also applicable to NP aggregates and agglomerates.