Effects of hydroxyapatite-coated nonwoven polyethylene/polypropylene fabric on non-mesodermal lineage-specific differentiation of human adipose-derived stem cells.

OBJECTIVE: Compared to other stem cells, the multipotency of human adipose-derived mesenchymal stem cells (ASCs) is limited. Effective approaches that trigger or enhance lineage-specific transdifferentiation are highly envisaged in the improvement of ASCs-based cell therapies. Using Immunofluorescence assays and the secretion of cardiac troponin T (cTnT) protein, we studied the impact of two substrates: Hydroxyapatite (HAp)-coated nonwoven polyethylene (PET)/polypropylene (PP) fabric and glass surfaces, representing 3 dimensional (D) and 2 D environments respectively, on the induction of cardiomyocytes - a non-mesodermal cell type from ASCs for 1-5 weeks. RESULTS: ASCs were successfully isolated from human adipose tissue under cGMP conditions. Within 1-3 weeks, expression of cTnT in the induced 3D cultures was overall significantly higher (P < 0.021) than that in the induced 2D cultures or controls (P < 0.0009). Remarkably, after 3 weeks of culture, cTnT secretion in the induced 3D cultures gradually declined, nearly reaching levels observed in the 2D cultures. The results show that HAp-coated nonwoven PE/PP fabric could enhance lineage-specific differentiation of ASCs toward cardiac-like cells. However, the fabric might suppress growth of the transformed cells. These preliminary findings encourage further interest in validating the fabric's potential in improving ASCs transdifferentiation.

A 3D Microfabricated Scaffold System for Unidirectional Cell Migration.

The present study demonstrates unidirectional cell migration using a novel 3D microfabricated scaffold, as revealed by the uneven sorting of cells into an area of 1 mm × 1 mm. To induce unidirectional cell migration, it is important to determine the optimal arrangement of 3D edges, and thus, the anisotropic periodic structures of micropatterns are adjusted appropriately. The cells put forth protrusions directionally along the sharp edges of these micropatterns, and migrated in the protruding direction. There are three advantages to this novel system. First, the range of applications is wide, because this system effectively induces unidirectional migration as long as 3D shapes of the scaffolds are maintained. Second, this system can contribute to the field of cell biology as a novel taxis assay. Third, this system is highly applicable to the development of medical devices. In the present report, unique 3D microfabricated scaffolds that provoked unidirectional migration of NIH3T3 cells are described. The 3D scaffolds could provoke cells to accumulate in a single target location, or could provoke a dissipated cell distribution. Because the shapes are very simple, they could be applied to the surfaces of various medical devices. Their utilization as a cell separation technology is also anticipated.

Modulation of surface stiffness and cell patterning on polymer films using micropatterns.

Here, a new technology was developed to selectively produce areas of high and low surface Young's modulus on biomedical polymer films using micropatterns. First, an elastic polymer film was adhered to a striped micropattern to fabricate a micropattern-supported film. Next, the topography and Young's modulus of the film surface were mapped using atomic force microscopy. Contrasts between the concave and convex locations of the stripe pattern were obvious in the Young's modulus map, although the topographical map of the film surface appeared almost flat. The concave and convex locations of a polymer film supported by a different micropattern also contrasted clearly. The resulting Young's modulus map showed that the Young's modulus was higher at convex locations than at concave locations. Hence, regions of high and low stiffness can be locally generated based on the shape of the micropattern supporting the film. When cells were cultured on the micropattern-supported films, NIH3T3 fibroblasts preferentially accumulated in convex regions with high Young's moduli. These findings demonstrate that this new technology can regulate regions of high and low surface Young's modulus on a cellular scaffold with high planar resolution, as well as providing a method for directing cellular patterning. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 976-985, 2018.