Preparation of cellulose nanocrystal/oxidized dextran/gelatin (CNC/OD/GEL) hydrogels and fabrication of a CNC/OD/GEL scaffold by 3D printing

Early reports have demonstrated the feasibility of oxidized dextran/gelatin (OD/GEL) hydrogel for tissue engineering applications and the printability of OD/GEL hydrogel for 3D printing scaffolds, but adequate insight into fabricated OD/GEL scaffolds is lacking. In the present study, we prepared (cellulose nanocrystal) CNC/OD/GEL hydrogels and fabricated CNC/OD/GEL scaffolds by 3D printing. The properties of CNC/OD/GEL hydrogels were investigated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy. The process of 3D printing of hydrogels was optimized, and the influence of the OD and CNC contents on the printability of CNC/OD/GEL hydrogels was investigated by studying the width of the printed filaments. The uniaxial compression test was performed to study the effects of the OD and CNC contents on the breaking strength and elastic modulus of CNC/OD/GEL scaffolds. In addition, the uniaxial compression test was also performed to determine the optimum mass ratio and crosslinking time of OD and GEL. The effects of the CNC content on scaffold shrinkage, scaffold swelling and scaffold porosity were further studied. The biocompatibility of a CNC0.4OD2G2 scaffold was also investigated by Cell Counting Kit-8 (CCK-8) and Hoechst 33342/PI double-staining assays. Collectively, the results confirmed the good potential of the CNC/OD/GEL hydrogels as 3D bioink for application in tissue repair.