Abstract
Although numerous materials have been explored as bone scaffolds, many of them are limited by their low osteoconductivity and high biodegradability. Therefore, new materials are desired to induce bone cell proliferation and facilitate bone formation. Attapulgite (ATP) is a hydrated silicate that exists in nature as a fibrillar clay mineral and is well known for its large specific surface area, high viscosity, and high absorption capacity, and therefore has the potential to be a new type of bone repair material due to its unique physicochemical properties. In this study, composite scaffolds composed of collagen/polycaprolactone/attapulgite (CPA) or collagen/polycaprolactone (CP) were fabricated through a salt-leaching method. The morphology, composition, microstructure, physical, and mechanical characteristics of the CPA and CP scaffolds were assessed. Cells from the mouse multipotent mesenchymal precursor cell line (D1 cells) were cocultured with the scaffolds, and cell adhesion, proliferation, and gene expression on the CPA and CP scaffolds were analyzed. Adult rabbits with radius defects were used to evaluate the performance of these scaffolds in repairing bone defects over 4–12 weeks. The experimental results showed that the cells demonstrated excellent attachment ability on the CPA scaffolds, as well as remarkable upregulation of the levels of osteoblastic markers such as Runx2, Osterix, collagen 1, osteopontin, and osteocalcin. Furthermore, results from radiography, micro-computed tomography, histological and immunohistochemical analysis demonstrated that abundant new bones were formed on the CPA scaffolds. Ultimately, these results demonstrated that CPA composite scaffolds show excellent potential in bone tissue engineering applications, with the capacity to be used as effective bone regeneration and repair scaffolds in clinical applications.
Highlights
Repairing bone defects caused by bone tumor resections, fracture defects, or chronic infection is still challenging in orthopedic practice1-3
We found that the expressions of collagen type 1 (COL1), alkaline phosphatase (ALP), OC, and OPN were significantly higher on CPA scaffolds than that on CP scaffolds, and this increased expression occurred in a dose-dependent and time-dependent manner
Salt leaching is an effective method of scaffold fabrication that has been used to create the macroporous scaffolds needed for bone tissue engineering51
Summary
Repairing bone defects caused by bone tumor resections, fracture defects, or chronic infection is still challenging in orthopedic practice. Autograft is the gold-standard approach in current bone repair. This technique has several disadvantages, including limited supply of bone tissue, induction of new trauma, and the potential for functional damage . Allografts are used clinically because of the availability in bone tissue supply, but these grafts carry the risk of infection, disease transmission, and the induction of immune response. Have the potential to address these challenges and promote bone regeneration and repair. Fabricating 3D porous scaffolds for cell migration, proliferation, differentiation, and nutrient delivery is challenging
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