In typical biofabrication and 3D bioprinting methods, layers of cell-laden hydrogel structures called bioinks are extruded to build functioning biological tissues. But using bioresins laden with cells, instead of bioinks, for lithography bioprinting methods, like digital light processing (DLP) and stereolithography (SLA), can be used to create patterns that are even more intricate than those possible with extrusion-based 3D printing; these patterns also do a better job of mimicking the complex architecture of tissue.
Associate Professor Tim Woodfield, who leads the Christchurch Regenerative Medicine and Tissue Engineering (CReaTE) Group in the Department of Orthopaedic Surgery and Centre for Bioengineering & Nanomedicine at the University of Otago Christchurch, in New Zealand, is leading a research team that has developed a bioresin for DLP technology that’s able to bioprint cell-laden hydrogel structures with small, high-resolution features of 25 to 50 microns.
The team’s DLP technique projects a patterned mask of UV or visible wavelength light, with a digital micro-mirror device, onto the bottom surface in a polymer resin bath. Once they’re exposed to this light, certain regions of the resin are polymerized, and the platform moves up to create a new layer.