Developing a novel bioink from hyaluronic acid-alginate-silk fibroin (HA- Alg-SF) for cartilage 3D printing

Abstract

In the development of a bioink for cartilage 3D printing, Hyaluronic acid (HA), Alginate (Alg) were modified into amine-hyaluronic acid (HA-NH2) and aldehyde alginate (Alg-CHO). Magnetic Nuclear Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR) confirmed the successful modification of HA-NH2 and Alg-CHO. The hydrogel HA-Alg was crosslinked as a result of Schiff's base reaction, between primary amines and aldehydes to form imine bonds. By varying volume ratios, the optimal hydrogel HA-Alg (5:5) exhibited its printability, biocompatibility, and functionality as a bioink for cartilage tissue. HA-Alg (5:5) was printable with a custom-made extrusion 3D printer, had slow degradation, shear-thinning behavior, supported cell viability, proliferation, and chondrogenic differentiation. To prove that HA-Alg could act as a platform for entrapment of macromolecules, Silk fibroin (SF) which is a biocompatible protein was loaded into HA-Alg formulation to develop HA-Alg-SF hydrogel. The results showed that HA-Alg-SF hydrogel adapted to 3D printing, and promoted cartilage tissue formation. The addition of SF did not compromise the printability and cell viability of HA-Alg-SF hydrogel comparing to HA-Alg hydrogel, which suggested that HA-Alg hydrogel could be an interpenetrating polymer network (IPN) for loading other proteins, and growth factors for further applications.