|Fluorescent quantum dots|
Quantum dots (QDs) are increasingly widespread in medicine and environmental research. Because of their specific optical characteristics, QDs can be detected by fluorescence analyses, even in complex media, such as environmental or tissue samples. Their unique properties make them useful for a variety of applications, such as for the use as fluorescent markers for cells, as contrast agents in deep tissue and tumour imaging, in biosensing or photodynamic therapy, and for targeted drug delivery. As a result, QDs could potentially be used as detectable and clearly identifiable “nanotracers” to mark or detect specific targets or to be able to draw general conclusions about the fate of engineered nanoparticles (ENPs) in environmentally relevant media, e.g. in wastewater. QDs mainly consist of metallic semiconductor compounds, such as cadmium selenide (CdSe), cadmium telluride (CdTe), lead sulphide (PbS) or indium phosphide (InP), which can have toxic effects on cells and organisms. Research is therefore being conducted on nontoxic carbonbased QDs, amongst others. QDs are already being used in products, such as TV screens and novel solar cell technologies. However, with an increasing number of applications and thusan increase in production volumes, potential exposure is also intensifying. Consequently, risks to humans and the environment are increasing as accidental release and resulting negative effects cannot be ruled out. To date,however, only limited data exist on possible environmental and health risks.