• 3D bioprinting
• Extracellular matrix
• Nephrotoxicity model
• Proximal tubule
• Tubule-on-chip

Drug development is a troublesome process that lasts from 12 to 15 years and requires millions of dollars, with high failure risk. Drug adverse effects on the kidneys are hard to be detected during early phases of drug development process, while they often became evident in the latest phases, causing drug candidate exiting clinical trials when a considerable amount of resources has already been spent. For these reasons, drug industries are strongly interested in searching for new methods which can forecast drug nephrotoxicity, preferably exploiting in vitro techniques, thus avoiding animal sacrifice.
The aim of this work is to study the design of a chip for nephrotoxicity evaluation, that models the segment of the nephron which is most targeted by drugs, the proximal tubule. The model presents 3D convolution, open lumen and possibility of being perfused. The design choices are reported, with attention to the fabrication technique that employs 3D bioprinter. Taking inspiration from the real composition of the human extracellular matrix, the suitability of the application of a mixture of Matrigel and Collagen I as extracellular matrix in the model is evaluated, giving attention to the effect of ECM composition and mechanical properties on cells behaviour.