Three-dimensional cell printing of gingival fibroblast/acellular dermal matrix/gelatin-sodium alginate scaffolds and their biocompatibility evaluation

Tissue engineering has emerged as a promising approach for soft tissue regeneration. Three-dimensional (3D) cell printing showed great potential for producing cell-encapsulated scaffolds to repair tissue defects. The advantage of 3D cell printing technology is precise cell loading in scaffolds to achieve tissue regeneration instead of only relying on the cells from surrounding tissue or blood. A new acellular dermal matrix/gelatin-sodium alginate (ADM/A/G) scaffold with living gingival fibroblasts was constructed by 3D cell printing technology for potential oral soft tissue regeneration in this study, and the biological characteristics of the 3D cell printing scaffolds were evaluated. The residue of nucleic acid and growth factors in ADM were detected. Three biomaterials were mixed at an appropriate radio with human gingival fibroblasts (hGFs) to prepare bioinks. Two kinds of layer scaffolds were fabricated by 3D cell printing technology. The mechanical strength and degradability of the scaffolds were determined by measuring their compressive modulus and mass loss. CCK-8 assay and calcein-AM/PI staining were conducted to detect the cell proliferation and viability in 3D cell printing scaffolds. The morphology of the hGFs in the scaffolds were observed using SEM and FITC-phalloidin staining. The expression of COL1A1, PECAM1, and VEGF-A of hGFs in the scaffolds were quantified by qRT-PCR. The gelatin-sodium alginate (A/G) scaffolds were used as control group in all experiments. Compared with the control group, 3D cell printing ADM/A/G scaffolds showed better mechanical strength and longer degradation time. The ADM/A/G scaffolds obviously had a better promotion effect on cell proliferation and viability. Most of the hGFs observed had a fully extended spindle morphology in the ADM/A/G scaffolds but oval morphology in the control group. The expression of COL1A1 was significantly higher than in the control group with time, and the expression of PECAM1 and VEGF-A was slightly higher in ADM/A/G scaffolds on day 14. 3D cell printing gingival fibroblast-ADM/A/G scaffolds showed excellent biological properties, which could be potentially useful in oral soft tissue regeneration.