Preparation and properties of sodium alginate-gelatin composite hydrogels with different topological structures by 3D printing

In this paper, the structure of skin dermal collagen fibers were simulated, and the sodium alginate (SA)-gelatin (GEL) composite scaffold with three topological angles of 45°, 60° and 90° were 3D printed to study the effect of topology on the performance of the hydrogel scaffold, respectively. SEM were used to characterize the microstructure of the scaffolds. The water content, porosity, mechanical properties, swelling ratio and in vitro degradation ratio of each group of scaffolds were measured. FTIR were used to test the functional groups of SA, GEL and composite hydrogel. Cell counting kit-8 (CCK-8) reagent and immunofluorescence staining were used to test the toxicity of the scaffolds to human dermal fibroblasts (HFb) and the biocompatibility of scaffolds. The results show that the topology of each group is clear. The relative position of the absorption peak in the FTIR spectrum provides the chemical structure of the scaffold material. The water content and porosity of the three groups are all greater than 80%. The compressive elastic modulus of the 45°, 60° and 90° scaffolds are (3.57±0.14) kPa, (3.18±0.31) kPa and (2.03±0.29) kPa, respectively. CCK-8 results show that the cell activity on three groups is maintained at more than 90% of control group without scaffolds. The results of microfilament and nuclear staining show that the spread of HFb on the 45° scaffold on the first day of inoculation is better than that of the other two groups, HFb proliferates significantly on the three groups of scaffolds with the increase of time, indicating that the scaffold has good cytocompatibility. This paper designs and characterizes the performance of SA-GEL scaffolds with different topologies, and provides an important foundation for the construction of subsequent tissue engineering dermis and the analysis of HFb collective migration on a three dimensional matrix. © 2022 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.