A universal self-eroding sacrificial bioink that enables bioprinting at room temperature

Natural polymer-based hydrogel bioinks are widely used in bioprinting due to their suitability for recapitulation of in vivo cellular activities. However, preservation of the target geometry in a cell-laden hydrogel is difficult to achieve. The aim of this study was to develop a universal sacrificial bioink that allows high cell viability and a better shape fidelity in the cell-laden construct. A polysaccharide-based universal sacrificial bioink was developed for microextrusion-based bioprinting and was optimized to erode in 48 hours in the cell culture medium without formation of any undesired by-products. The sacrificial hydrogel was prepared from alginate and agarose via a microwave oven assisted method and bioprinted at room temperature to generate microchannels in the cell-laden hydrogel or to support a tubular structure and its biocompatibility determined by live/dead assay. Bioprinting time was significantly reduced, down to a few minutes for a large-scale tissue model (1 minute 52 seconds for a 2 cm tubular structure), by means of a high bioprinting speed up to 25 mm/s. After 48 hours in the cell culture, the sacrificial bioink completely detached from the cell-laden construct without causing any changes in its printed shape. Cell viability in the cell-laden construct was observed to be more than 95% at the end of 3-day culture. This novel sacrificial bioink enables bioprinting at room temperature without affecting oxygen and nutrient penetration into the cell-laden hydrogel and allows retention of high cell viability and shape fidelity.