Spheroid-Matrix Kidney-on-a-Chip Model for Predicting Drug-Induced Nephrotoxicity

Drug-induced nephrotoxicity remains a significant clinical challenge, contributing to many acute kidney injury cases. Current preclinical models often lack predictive accuracy, and ethical concerns surrounding animal use require the development of alternative in vitro systems. This study aims to design a physiologically relevant kidney-on-a-chip to predict drug-induced nephrotoxicity. The model comprises a three-dimensional (3D) microfluidic device incorporating co-cultured renal proximal tubule epithelial cells (RPTEC) and human umbilical vein endothelial cells (HUVEC) spheroids embedded within a gelatin–fibrin hydrogel matrix. The elastic modulus of the matrix closely mimics the native kidney tissue and supports spheroid viability and proliferation. Co-cultured spheroids exhibited the formation of organized tubule-like structures and enhanced physiological relevance, demonstrating synergistic effects on growth and improved resistance to drug-induced nephrotoxicity compared with monocultures. Furthermore, these spheroids exhibited glucose and albumin reabsorption capabilities, as key indicators of proximal tubule function. The responsiveness of the kidney-on-a-chip to the nephrotoxic agent amphotericin B demonstrated its potential for preclinical drug testing and toxicity assessments. Our kidney-on-a-chip offers a novel platform for in vitro nephrotoxicity testing, aligned to the 3Rs principles of animal research.