Development and Characterization of Complementary Polymer Network Bioinks for 3D Bioprinting of Soft Tissue Constructs.

The development of 3D bioprinting has been hindered by a narrow "biofabrication window" with a limited variety of feasible bioinks which are compatible with both high printability and well cytocompatibility. Herein, a generalizable strategy using complementary polymer network (CPN) bioinks is developed in the current study, to address the conflict between the printability and cytocompatibility of bioinks in extrusion 3D bioprinting, especially for the manufacture of soft tissue constructs. In this strategy, CPN bioinks are formed though mixing two interpenetrated polymer networks, one of which is a photocrosslinkable polymer network, and the other is a dynamic polymer network crosslinked by reversible covalent linkage, thereby endowed with well reversible thixotropy. Compatible with well printability, shape fidelity, and cytocompatibility, the utilization of CPN bioinks provides a viable solution for extrusion 3D bioprinting of photocrosslinkable biomaterials at a low concentration, thus suitable for soft tissue construct fabrication. Briefly, this study is testified to be a successful attempt to extend the bioink diversity within the "biofabrication window," and offers a novel insight into designing more feasible bioinks based on their special rheological properties, for further tissue engineering and biomedicine application.