Three-Dimensional Cell Printed Lock-Key Structure for Oral Soft and Hard Tissue Regeneration.

Abstract

Alveolar ridge absorbs rapidly following tooth extraction. To promote implant rehabilitation, an adequate bone and soft tissue volume are required. Three-dimensional (3D) cell printing technique provides the advantages of precise spatial distribution and personalization. In this study, 3D cell printing was used to establish a soft-hard construct that is composed of alginate/gelatin (AG)/gingival fibroblast cells (GFs) and alginate/gelatin/nano-hydroxyapatite (AGH)/bone marrow-derived mesenchymal stem cells (BMSCs). Physicochemical results showed that nano-hydroxyapatite (nHA) added in the bioink maintained its crystalline phase. In addition, an increase of viscosity, the improvement of compressive modulus (P＜0.01), and slow degradation rate (P＜0.01) were found after adding nHA. SEM showed cell stretched and attached well on the surface of the 3D printed construct. At day 7 after printing, the viability of GFs in AG was 94.80%±1.14, while BMSCs viability in AGH was 86.59%±0.75. PCR results indicated that the expression levels of ALP, RUNX-2, and OCN in BMSCs were higher in AGH than AG bioink (P＜0.01). After 8-week implantation into the dorsum of 6-8-week-old male BALB/c nude mice, the cellular printed construct displayed a more integrated structure and better healing of subcutaneous tissue compared with the acellular printed construct. In conclusion, this 3D cell printed soft-hard construct exhibits favorable biocompatibility and has potential for alveolar ridge preservation.