Bioprinting of Alginate-Norbornene Bioinks to Create a Versatile Platform for Kidney in Vitro Modeling

Chronic kidney diseases affect a significant portion of the global population and their prevalence is expected to increase in the coming years. Advanced in vitro models are crucial for understanding disease onset and for improving drug testing. Emerging strategies have enhanced the accuracy of these models by incorporating 3D culture and perfusion systems. Notably, efforts have focused on modeling the nephron, particularly endothelialized and epithelialized tubular structures, with perfusion to simulate toxin exchange for nephrotoxicity testing. New approaches combining biomaterials with patient-derived kidney epithelial cells show promise for high-throughput personalized drug screening. However, these methods often rely on decellularized extracellular matrix materials, such as Matrigel® and collagen, which suffer from batch-to-batch variability. To address reproducibility issues, we used norbornene-functionalized alginate to produce peptide-functionalized thiolene crosslinked hydrogels. By varying the composition of crosslinkers and peptide functionalization, we tuned the cell interaction with the hydrogels. The rapid reaction kinetics enabled the bioprinting of cell-laden tubular structures using microfluidic bioprinting, without the need for ionic crosslinking, by adapting the printer with UV irradiation at the nozzle. The bioprinted fibers successfully formed monolayers, indicating their potential for creating advanced kidney in vitro models. Thiol-ene crosslinked hydrogels proved to be highly tunable and adaptable to microfluidic bioprinting, demonstrating significant promise for further application to create kidney in vitro models.