Bioprocessing of Tissues Using Cellular Spheroids

Tissue engineering combines the principles of engineering and life sciences in order to repair, restore and regenerate tissues and organs that mimic the functionality and mechanical properties of native tissues [1,2]. In the United States, there are 121,000 people currently waiting for lifesaving organ transplants (kidney, liver, heart) and tissue engineering offers new hope and therapeutic opportunities for these patients [3,4]. The classic approach to tissue engineering involves seeding living cells onto a solid biocompatible and eventually a biodegradable scaffold, and then culturing the tissue engineered construct in a bioreactor until the tissue achieves the desired cell density and mechanical properties for implantation [2]. However, new approaches that build 3D tissues with a bottom up approach using cellular spheroids are offering new possibilities. Rapid tissue fabrication approaches using spheroids have three key bioprocessing steps that lead to the development of 3D tissue structures: (1) preprocessing, (2) processing, and (3) post-processing.