Enhanced chondrogenic differentiation of dental pulp stem cells using nanopatterned PEG-GelMA-HA hydrogels

We have examined the effects of surface nanotopography and hyaluronic acid (HA) on in vitro chondrogenesis of dental pulp stem cells (DPSCs). Ultraviolet-assisted capillary force lithography was employed to fabricate well-defined nanostructured scaffolds of composite PEG-GelMA-HA hydrogels that consist of poly(ethylene glycol) dimethacrylate (PEGDMA), methacrylated gelatin (GelMA), and HA. Using this microengineered platform, we first demonstrated that DPSCs formed three-dimensional spheroids, which provide an appropriate environment for in vitro chondrogenic differentiation. We also found that DPSCs cultured on nanopatterned PEG-GelMA-HA scaffolds showed a significant upregulation of the chondrogenic gene markers (Sox9, Alkaline phosphatase, Aggrecan, Procollagen type II, and Procollagen type X), while downregulating the pluripotent stem cell gene, Nanog, and epithelial-mesenchymal genes (Twist, Snail, Slug) compared with tissue culture polystyrene-cultured DPSCs. Immunocytochemistry showed more extensive deposition of collagen type II in DPSCs cultured on the nanopatterned PEG-GelMA-HA scaffolds. These findings suggest that nanotopography and HA provide important cues for promoting chondrogenic differentiation of DPSCs.