Impact of Different Proportions of 2D and 3D Scaffolds on the Proliferation and Differentiation of Human Adipose-Derived Stem Cells.

Purpose: To observe the proliferation and differentiation of human adipose-derived stem cells (hADSCs) on 2D and 3D scaffolds, the sodium alginate and collagen interpenetrating network hydrogel were developed to determine optimal properties for bone tissue engineering.

Methods: Three groups of scaffold materials were prepared according to the ratio of sodium alginate to collagen: A (4:1), B (2:1), and C (1:1), respectively. For each group, gel beads (3D surfaces) and freeze-dried films (2D surfaces) were respectively prepared. For gel beads, hADSCs were mixed during the preparation of the beads, and then stem cells were applied to the surface of each film after freeze-drying and sterilization during the preparation of the freeze-dried films. Cell proliferation and osteogenic differentiation potential were detected by cell counting kit, viable/dead cell staining kit, quantitative reverse transcription polymerase chain reaction, and immunofluorescent staining, respectively.

Results: Results showed that cell proliferation rate progressively increased with the increase of collagen ratio, with group C of 3D surfaces of gel beads achieving the highest rate. In particular, highest cell viability on the 2D surfaces was achieved in group B. Differences in BGLAP and RUNX2 expression in hADSCs on 2D or 3D surfaces of the 3 groups were statistically significant. Particularly, BGLAP and RUNX2 gene expression levels were highest in group C of freeze-dried films and were highest in group B of gel beads. Furthermore, the trend of immunofluorescence expression of RUNX2 and osteocalcin expression were consistent with the genetic testing results.

Conclusions: All data indicated that sodium alginate-collagen scaffolding materials had no adverse impact on the proliferation and osteogenic differentiation of hADSCs. Cell differentiation and proliferation of bone tissue engineering can be promoted with the use of sodium alginate and collagen interpenetrating network hydrogel, and the appropriate ratio of sodium alginate and collagen is 2:1.