Nynke Kramer is assistant professor in Toxicology at the Institute for Risk Assessment Sciences (IRAS) of Utrecht University. Nynke heads its 'In Vitro Toxicology' group. She teaches toxicokinetics, pharmacokinetic modeling, ecotoxicology, toxicological risk assessment and quantitative in vitro-in vivo extrapolation at graduate and postgraduate level. Her research focuses on developing techniques and models to improve the extrapolation of effect concentrations obtained from in vitro cell assays to toxic doses relevant to humans and animals. Her current research follows up on her PhD thesis, completed at the same institute in 2010. Her research has led to a number of publications uncovering parameters determining the free concentration of test chemicals in in vitro cell assays. The issue of free concentrations in in vitro assays has slowly picked up momentum. Illustratively, Nynke’s research has been awarded the SETAC Procter and Gamble Fellowship for Doctoral Research in Environmental Sciences. She used the prize money to do part of her research at the Swiss Federal Institute for Aquatic Science and Technology, Eawag, Dübendorf, Switzerland. Before starting her PhD, Nynke obtained her BSc degree (summa cum laude) in Life Sciences at University College Utrecht and her MSc degree (distinction) in Environmental Change and Management at the University of Oxford.