Tóm tắt

For bone tissue engineering applications, scaffolds that mimic the porous structure of the extracellular matrix arernhighly desirable. Herein, we employ a PCL/HA-based scaffold with a double-scaled architecture of small poresrncoupled to larger ones. To improve the osteoinductivity of the scaffold, we incorporate two different growthrnfactors via polydopamine (PDA) coating. As a first step, we identify the maximum amount of PDA that can berndeposited onto the scaffold. Next, to allow for the deposition of a second PDA layer which, in turn, will allow tornincrease the loading of growth factors, we incorporate a dithiol connecting layer. The thiol groups covalentlyrnreact with thefirst PDA coating through Michael addition while also allowing for the incorporation of a secondrnPDA layer. We load thefirst and second PDA layers with bone morphogenic protein-2 (BMP2) and vascularrnendothelial growth factor (VEGF), respectively, and evaluate the osteogenic potential of the functionalisedrnscaffold by cell viability, alkaline phosphatase activity and the expression of three different osteogenesis-relatedrngenes of pre-seeded human mesenchymal stem cells. Through these studies, we demonstrate that the osteogenicrnactivity of the scaffolds loaded with both BMP2 and VEGF is greater than scaffolds loaded only with BMP2.rnImportantly, the osteoinductivity is higher when the scaffolds are loaded with BMP2 and VEGF in two differentrnPDA layers. Taken together, these results indicate that the as-prepared scaffolds could be a useful construct forrnbone-tissue applications.