A Composite Hydrogel and its 3D Printing of Scaffolds for Liver Tissue Engineering

Different liver diseases can cause liver failure. Liver transplantation is currently the only viable therapy for patients with very compromised liver functions but it faces major obstacles. Liver tissue engineering (LTE) provides an alternative means for patients. 3D printing are capable of fabricating complex cell-scaffold constructs that bear resemblance in form and functionality to native body tissues. By recapitulating the microenvironment features of tissues, printed constructs can serve as in vitro models of native tissue for basic research or can be translated into implantable devices for clinic use. As a class of biomaterials, hydrogels are uniquely suited for such applications via 3D printing, which will recapitulate many features of the native extracellular matrix. This study firstly prepared double-bond modified carboxymethyl chitosan and aldehyde-based hyaluronic acid. The polymers were then mixed with collagen to form composite hydrogel inks for extrusion-based 3D printing. Various experiments were conducted to assess hydrogel inks and 3D printed scaffolds. The results showed good printability of optimized hydrogel inks and high fidelity of printed grid scaffolds from these optimized inks. Mechanical properties of printed hydrogel scaffolds were similar to those of normal liver. In vitro biological study revealed high proliferation of normal hepatocytes on printed hydrogel scaffolds. The new composite hydrogel appears promising for 3D printing of LTE scaffolds.