Microfluidic bioprinting as a tool to produce hiPSCs-derived renal organoids.

Chronic kidney disease affects 10% of the global population and often progresses to end-stage renal disease, where dialysis or renal transplant are the only therapies, though neither is a permanent solution. Regenerative medicine, particularly the use of organoids, offers a potential solution. Organoids are valuable for studying organ development, diseases, and regeneration, and are suitable for drug screening. However, their limited ability to replicate adult organs' maturation, complexity, and functions restricts their application. Additionally, manual production of organoids causes variability, affecting scalability and reproducibility. Automation techniques like bioprinting could enhance organoid maturation and complexity by depositing cells and biomaterials in a controlled manner. In this study, we established differentiation protocols to obtain human induced pluripotent stem cell-derived metanephric mesenchyme, ureteric bud progenitors, and the combination of these was used to form organoids. A microfluidic bioprinter capable of producing core-shell filaments was used to bioprint single cell progenitors in combination with gelatin in the core wrapped with an alginate shell. These filament constructs were cultured with an optimized mixture of growth factors for two weeks. Within one week, renal vesicles were visible, and after two weeks post-bioprinting the kidney organoids were functional and respond to the nephrotoxic drug doxorubicin. In conclusion, a bioprinted method was developed to generate in an automated way functional renal organoids from progenitors, offering a foundation for future kidney disease treatment.