Micropore-induced capillarity enhances bone distribution in vivo in biphasic calcium phosphate scaffolds

Abstract

The increasing demand for bone repair solutions calls for the development of efficacious bone scaffolds. Biphasic calcium phosphate (BCP) scaffolds with both macropores and micropores (MP) have improved healing compared to those with macropores and no micropores (NMP), but the role of micropores is unclear. Here, we evaluate capillarity induced by micropores as a mechanism that can affect bone growth in vivo. Three groups of cylindrical scaffolds were implanted in pig mandibles for three weeks: MP were implanted either dry (MP-Dry), or after submersion in phosphate buffered saline, which fills pores with fluid and therefore suppresses micropore-induced capillarity (MP-Wet); NMP were implanted dry. The amount and distribution of bone in the scaffolds were quantified using micro-computed tomography. MP-Dry had a more homogeneous bone distribution than MP-Wet, although the average bone volume fraction, , was not significantly different for these two groups (0.45±0.03 and 0.37±0.03, respectively). There was no significant difference in the radial bone distribution of NMP and MP-Wet, but the of NMP was significantly lower among the three groups (0.25±0.02). These results suggest that micropore-induced capillarity enhances bone regeneration by improving the homogeneity of bone

Effect of the nano/microscale structure of biomaterial scaffolds on bone regeneration

“…Bouler et al reported the BCP scaffolds with multi-scale porosity and a composition of 87% HA and 13% β-TCP, exhibited a good bioactivity and positive effect on bone growth when implanted in porcine mandibular defects. 13 As a matter of fact, ceramic biomaterials have some advantages such as good biocompatible as well as resistant to compression and corrosion, but their brittleness and low tensile strength need to be improved. 14 The second category consists of natural polymers, such as chitosan (CTS), collagen (Col), fibrin, hyaluronic acid, and synthetic polymers including polycaprolactone (PCL), polyglycolic acid (PGA), polylactic acid (PLA), poly (vinylphosphonic acid) (PVPA).…”

Evaluation of Structural and Mechanical Properties of Porous Artificial Bone Scaffolds Fabricated via Advanced TBA-Based Freeze-Gel Casting Technique

“…Woodard et al [18] indicated that pores having a diameter of more than 300 µm connect tissues such as blood vessels surrounding the bone defect, and pores 50 µm in diameter are used for bone regeneration and are advantageous for expanding specific surfaces. Rustom et al [19] fabricated two types of calcium phosphate scaffolds; one had both macropores and micropores and other had only macropores. It was shown that large interconnected macropores (>300 µm) provide space for bone ingrowth, vascularization, and innervation, and that micropores (<20 µm) improve the capillarity of bone scaffolds which increase the amount and the variety of cells drawn through the microporous network.…”

Cemented injectable multi-phased porous bone grafts for the treatment of femoral head necrosis

“…Calcium phosphate cement has shown better biocompatibility and is a widely used biomaterial due to its chemical and structural similarity to the inorganic component of bone. 35,36 The extraction medium, which triggered ion release in our study, was not diluted in the cell culture compared with other studies 37,38 so that a small amount of toxicity was observed. However, it showed better performance when implanted in vivo because of the flowing interstitial fluid.…”

“…However, it showed better performance when implanted in vivo because of the flowing interstitial fluid. 38…”