Intrinsic osteoinductivity of PCL‐DA/PLLA semi‐IPN shape memory polymer scaffolds

Abstract Engineering osteoinductive, self‐fitting scaffolds offers a potential treatment modality to repair irregularly shaped craniomaxillofacial bone defects. Recently, we innovated on osteoinductive poly(ε‐caprolactone)‐diacrylate (PCL‐DA) shape memory polymers (SMPs) to incorporate poly‐L‐lactic acid (PLLA) into the PCL‐DA network, forming a semi‐interpenetrating network (semi‐IPN). Scaffolds formed from these PCL‐DA/PLLA semi‐IPNs display stiffnesses within the range of trabecular bone and accelerated degradation relative to scaffolds formed from slowly degrading PCL‐DA SMPs. Herein, we demonstrate for the first time that PCL‐DA/PLLA semi‐IPN SMP scaffolds show increased intrinsic osteoinductivity relative to PCL‐DA. We also confirm that application of a bioinspired polydopamine (PD) coating further improves the osteoinductive capacity of these PCL‐DA/PLLA semi‐IPN SMPs. In the absence of osteogenic supplements, protein level assessment of human mesenchymal stem cells (h‐MSCs) cultured in PCL‐DA/PLLA scaffolds revealed an increase in expression of osteogenic markers osterix, bone morphogenetic protein‐4 (BMP‐4), and collagen 1 alpha 1 (COL1A1), relative to PCL‐DA scaffolds and osteogenic medium controls. Likewise, the expression of runt‐related transcription factor 2 (RUNX2) and BMP‐4 was elevated in the presence of PD‐coating. In contrast, the chondrogenic and adipogenic responses associated with the scaffolds matched or were reduced relative to osteogenic medium controls, indicating that the scaffolds display intrinsic osteoinductivity.