Bacterial Toxicity of Germanium Nanocrystals Induced by Doping with Boron and Phosphorus

Though characterized by excellent optical and electronic performance, traditional cadmium (Cd)- or lead (Pb)-based semiconductor nanocrystals, namely quantum dots, are arousing environmental concerns due to the toxic heavy metal contents. In this context, germanium nanocrystals have sparked research interests in recent years as germanium is conventionally regarded as an environmentally benign element. While it is well-known that doping with p/n-type impurities (such as boron/phosphorus) can tune the original performance of semiconductor materials, few efforts have been devoted to investigating how doped germanium nanocrystals may influence the environment if released into the ecosystem. In this study, we demonstrate that the addition of dopants induces the production of reactive oxygen species, leading to significant toxic effects toward a model organism, Shewanella oneidensis MR-1.