Abstract
The advancement of "kidney-on-a-chip" platforms - submillimeter-scale fluidic systems designed to recapitulate renal functions in vitro - directly impacts a wide range of biomedical fields, including drug screening, cell and tissue engineering, toxicity testing, and disease modelling. To fabricate kidney-on-a-chip technologies, researchers have primarily adapted traditional micromachining techniques that are rooted in the integrated circuit industry; hence the term, "chip." A significant challenge, however, is that such methods are inherently monolithic, which limits one's ability to accurately recreate the geometric and architectural complexity of the kidney in vivo. Better reproduction of the anatomical complexity of the kidney will allow for more instructive modelling of physiological and pathophysiological events. Emerging additive manufacturing or "three-dimensional (3D) printing" techniques could provide a promising alternative to conventional methodologies. In this article, we discuss recent progress in the development of both kidney-on-a-chip platforms and state-of-the-art submillimeter-scale 3D printing methods, with a focus on biophysical and architectural capabilities. Lastly, we examine the potential for 3D printing-based approaches to extend the efficacy of kidney-on-a-chip systems.