PCBs (polychlorinated biphenyls) are synthetic molecules that were used in transformers, electric motors, and more applications from the 1930s onwards. It was quickly discovered that these molecules are toxic, and subsequently, they were banned. Still, their heavy use then and their long half-life still cause PCB contamination today. As dietary intake is the main source of exposure, it often finds its way into our food chains trough fish. It has been linked to alterations in reproduction, the endocrine system, and organ functioning in both animals and humans. In addition, epidemiological studies have found a link between PCB exposure and ADHD.
Ever heard of quantum dots? These dots are nanoparticles made of a semiconductor material, which have unique optical properties: the wavelength (and thus color) of their light emission depends on their size, rather than the material they are made of. This is why they are of great interest for fields such as biological imaging, medical diagnostics, drug delivery, and gene therapy.