The present invention relates to microfluidic fluidic devices, methods and systems as microfluidic kidney on-chips, e.g. human Proximal Tubule-Kidney-Chip, Glomerulus (Kidney)-Chip, Collecting Duct (Kidney)-Chip. Devices, methods and systems are described for drug testing including drug transport and renal clearance. Further, such devices, methods and systems are used for determining drug-drug interactions and their effect upon renal transporter functions. Importantly, they may be used for pre-clinical and clinical drug development for treating kidney diseases and for personalized medicine.