Organ Bioprinting as the Pinnacle of Tissue Engineering

This article serves as a high level overview of the present state of bioprinting of three-dimensional sections of living tissue. The field has stalled at the hurdle of vascularization for more than a decade now; it has proven to be challenging to make the leap from tiny functional organoid tissues to something larger. It isn't just the matter of building in capillary and larger blood vessel networks, however. Organoids are largely only approximations to real structured tissue, good enough to be functional in many respects, but not the final goal. In order to build sizable sections of organs with bioprinters, a great deal of work remains in order to be able to create structures that more closely, usefully match those of the body, even given that many of the pieces of that puzzle already exist.

Bioprinting is still in its infancy and bogged down by various challenges related to different aspects of the bioprinting process. The primary challenge is developing an ideal bioink that is apt for the tissue of interest to be printed. Maintaining adequate cell density and viability following extrusion, obtaining air bubble-free extruded filaments, achieving adequate mechanical strength post-printing, achieving vascularization and innervation of the tissue constructs, and printing complete organs are the major challenges slowing down the bioprinting process. Research is being conducted to overcome these hurdles and provide personalized treatment solutions for regenerating the lost tissues.

Gaining in-depth knowledge regarding the organogenesis process, the tissue structure, composition, and behavior of each tissue, ways to maintain cell viability, and tissue integration with the native tissue post-printing would enable us to overcome these challenges one step at a time. 4D bioprinting has recently emerged, where time is considered the fourth dimension of printing. The printed scaffold modulates their organization and behavior according to time-dependent external stimuli. The future is moving toward five-dimensional (5D) printing, which will occur in multiple rotational axes.

Advanced bioprinting technologies would greatly reduce the demand for organ donations. Government organizations and regulators are still working toward achieving a balance between the need for organ donation through early prevention and management of diseases and improved procurement of organs. Application of bioprinting technologies would greatly reduce the burden on the governments and buy us time till every nation becomes self-sufficient to manage the need for organ donations. Though the setting up of a bioprinting center of excellence is a costly affair, in terms of obtaining the infrastructural and biologics support, the number of lives saved through its applications in regenerative and rehabilitative medicine is of paramount significance.