A Comprehensive Characterization Study of Alginate-Gelatin-Tempo Mediated Nano Fibrillated Cellulose Composites for Extrusion-Based 3D Bioprinting Technique

Alginate's viscosity enhancement capacity by ionic crosslinking combined with Gelatin's cell-binding motifs, have elevated their role in extrusion-based 3D bioprinting. Gelatin shows improved cell functions due to the resemblance of collagen's structure, featuring RGD peptides. While pure gelatin faces temperature-related extrusion challenges, alginate supplementation helps. Even though Nano-fibrillated cellulose (NFC) augments hydrogel properties, it suffers due to uneven network entanglements. Surface modification via TEMPO oxidation produces TO-NFC, mitigating printability issues. TO-NFC's hydrogen-bonded crystallinity post-oxidation positions it as a robust bio-ink for 3D scaffold creation. In this paper, we will prepare a set of compositions using Alginate (2-5.25%), Gelatin (2-5.25%), and TO-NFC (0.5-1.0%) maintaining a total solid content of 8% to harness their combined benefits in the field of extrusion-based bio-printing process. We will identify the printability, shape fidelity, and biocompatibility of those compositions by conducting a series of characterization tests such as rheological test, scanning electronics microscopy (SEM), FTIR, thermal tests, and cytotoxicity encapsulating Human Mesenchymal Stem Cells (hMSCs). The outcome of those tests such as flow behavior, microporosity, chemical bonds, and cell viability will help identify the optimum composition/s for 3D bioprinting applications. The ability to control 3D printability and the favorable survival of cells make nanofiber infused alginate-gelatin a promising option for creating precisely shaped scaffolds using the 3D bio-printing process.