Comparative evaluation of morphology and osteogenic behavior of human Wharton's jelly mesenchymal stem cells on 2D culture plate and 3D biomimetic scaffold.

Expansion of seeded human Wharton's jelly mesenchymal stem cells (hWJ-MSCs) on 2D culture plates and 3D nano-hydroxyapatite/chitosan/gelatin scaffolds, from morphology and osteoactivity points of view, were investigated. Cell attachment and spreading, temporal expression profiles of selected osteogenic gene and protein markers, intracellular alkaline phosphatase enzyme activity (ALP activity), and matrix mineralization were assayed over the course of the experiments. Morphological results demonstrated hWJ-MSCs had greater affinity to adhere onto the 3D scaffold surface, as the number and thickness of the filopodia were higher in the 3D compared with 2D culture system. Functionally, the intracellular ALP activity and extracellular mineralization in 3D scaffolds were significantly greater, in parallel with elevation of osteogenic markers at the mRNA and protein levels at all-time point. It is concluded that 3D scaffolds, more so than 2D culture plate, promote morphology and osteogenic behavior of WJ-MSCs in vitro, a promising system for MSCs expansion without compromising their stemness before clinical transplantation.

In vitro interaction of human Wharton's jelly mesenchymal stem cells with biomimetic 3D scaffold.

Study of cell-biomaterial interaction is a crucial aspect of bone tissue engineering to find a state-of-the-art functional substitute. In present study, the Wharton's jelly mesenchymal stem cells (hWJ-MSCs) behavior on three-dimensional biomimetic nano-hydroxyapatite/chitosan/gelatin (nHA/CS/Gel) scaffolds was investigated. The outcome was assessed by histological, biochemical and morphological tests. Results indicated that hWJ-MSCs attached onto the scaffold surface through membrane filopodia, uniformly spread throughout the contacting surface. It only took 3 days for the seeded cells to appear deep inside the scaffold, reflecting proper hWJ-MSCs adhesion and migration, evidenced by both scanning electron microscope and hematoxilin and eosin assessments. Additionally, the present fabricated nHA/CS/Gel scaffold proved to be non-toxic as it supported cell proliferation measured by 3-(4,5-dimethylthiazoyl-2-yl)-2,5-diphenyltetrazolium bromide assay. Moreover, 3-week culture of hWJ-MSCs on scaffolds, immersed in osteogenic medium, rendered the microenvironment in favor of hWJ-MSCs differentiation into osteoblast cells and extracellular matrix secretion. Finally, osteoblasts were immunologically positive for various osteogenic markers including osteocalcin, osteopontin, osteonectin, and alkaline phosphatase. Present findings indicate that nHA/CS/Gel scaffold appropriately harbored hWJ-MSCs, stimulating their growth, migration, proliferation, and differentiation. hWJ-MSCs-loaded nHA/CS/gel substitute may therefore be considered as a suitable platform for the rising demand in in vivo bone repair studies. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1166-1175, 2019.