Collagen/Cellulose Nanofiber Blend Scaffolds Prepared at Various pH Conditions

Living tissues modules consist of highly organized cells and extracellular matrices (ECMs) in a hierarchical manner. Among these ECMs, type I collagen (COL), which is the most abundant protein, is widely accepted in the tissue engineering field due to its biocompatibility. However, improvement of mechanical properties of COL scaffolds still remains a challenge. We prepared the scaffold sheets with blends of COL and 2,2,6,6-tetramethylpiperidine-1-oxil(TEMPO)-oxidized cellulose nanofiber (TOCN). TOCNs with high mechanical properties reinforced COL scaffolds. Moreover, we prepared their blends under various pH conditions and investigated their mechanical properties and biocompatibilities. Sheets prepared at a higher pH possess a better mechanical performance. From Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy measurements, it is proved that the higher mechanical properties were attributed to COL triple inter helix structure, hydrogen interaction, and electrostatic interaction with TOCN. The biocompatibilities of COL/TOCN prepared at a higher pH were increased. We successfully demonstrated COL/TOCN blend materials with a high mechanical strength and high biocompatibility for scaffold materials.