Shear-Thinning and Thermo-Reversible Nanoengineered Inks for 3D Bioprinting.

Three-dimensional (3D) printing is an emerging approach for rapid fabrication of complex tissue structures using cell-loaded bioinks. However, 3D bioprinting has hit a bottleneck in progress because of the lack of suitable bioinks that are printable, have high shape fidelity, and are mechanically resilient. In this study, we introduce a new family of nanoengineered bioinks consisting of kappa-carrageenan (κCA) and two-dimensional (2D) nanosilicates (nSi). κCA is a biocompatible, linear, sulfated polysaccharide derived from red algae and can undergo thermo-reversible and ionic gelation. The shear-thinning characteristics of κCA were tailored by nanosilicates to develop a printable bioink. By tuning κCA-nanosilicate ratios, the thermo-reversible gelation of the bioink can be controlled to obtain high printability and shape retention characteristics. The unique aspect of the nanoengineered κCA-nSi bioink is its ability to print physiologically-relevant-scale tissue constructs without requiring secondary supports. We envision that nanoengineered κCA-nanosilicate bioinks can be used to 3D print complex, large-scale, cell-laden tissue constructs with high structural fidelity and tunable mechanical stiffness for regenerative medicine.