Effect of pore size in bone regeneration using polydopamine-laced hydroxyapatite collagen calcium silicate scaffolds fabricated by 3D mould printing technology.

Abstract

The pore size of the scaffold is a critical factor in repairing large bone defect. Here, we investigated the potential of bone regeneration using novel nanocomposite polydopamine-laced hydroxyapatite collagen calcium silicate (HCCS-PDA) scaffolds with two different pore sizes, 250 and 500μm. A total of 12 male Sprague-Dawley rats were implanted with HCCS-PDA scaffold with pore size of either 250 or 500μm into surgically created critical-sized defect (CSD). HCCS-PDA scaffolds were fabricated using mould printing technique. The effect of pore size on mechanical strength of the scaffolds was assessed by compression testing. After seeding with rat mesenchymal stem cells (rMSCs), the scaffolds were implanted, and new bone formation was evaluated using microCT and histomorphometric analysis after 8weeks. MicroCT and histology analysis demonstrated restricted peripheral new bone formation in either dural or periosteal side and limited new bone formation in the 250μm pore scaffold. Conversely, the 500-μm pore scaffold showed more penetration of new bone into the scaffold and greater bone regeneration in the rat CSD. Based on our results, which demonstrated improved new bone formation in 500μm pores scaffold, we can conclude that effective scaffold pore size that induces osteointegration and bone regeneration is around 500μm for HCCS-PDA nanocomposite scaffold.