Exploring the Impact of Volumetric Additive Manufacturing of Photo-crosslinkable Gelatin on Mesenchymal Stromal Cell Behavior and Differentiation

This study explores the application of photo-crosslinkable gelatin hydrogels (constituting GelSH and GelNB) for biofabrication using volumetric additive manufacturing (VAM). Three GelSH variants were prepared, yielding degree of substitutions (DS) of 39%, 54%, and 63%, and GelNB with a DS of 60%, alongside GelNB-GelSH formulations at concentrations of 5, 7.5, and 10% (w/v). Physico-chemical analyses confirmed that these variations led to differences in mass swelling ratio and mechanical properties. VAM enabled the fabrication of complex, high-fidelity 3D structures from the optimized GelNB-GelSH formulations, demonstrating its capacity to encapsulate mesenchymal stromal cells (MSCs) within a biomimetic matrix. Compared to the film casted constructs, the VAM-printed scaffolds exhibited significantly higher ALP activity and calcium deposition, confirming effective osteogenesis. Conversely, chondrogenic and adipogenic differentiation were more pronounced in the film casted groups due to their lower crosslinking density and lower compressive elastic modulus, emphasizing the role of the mechanical environment role in guiding cell differentiation. This study highlights the potential of VAM to produce complex and functional hydrogel scaffolds for tissue engineering, and lays the groundwork for future work on finetuning bioresin formulations to enhance differentiation across multiple lineages for various tissue engineering applications, including softer tissues.