A comparative study of the physical and mechanical properties of three natural corals based on the criteria for bone–tissue engineering scaffolds

Abstract

Coral has been used for bone grafts since 1970. Because coral has the advantages of good osteoconduction, biocompatibility, and biodegradation, it is also suitable for scaffolds used in bone-tissue engineering. However, the skeletons of different species of corals often vary significantly, and very few studies focus on the assessment of the permeability and mechanical properties of coral structure. In order to better understand the use of coral in bone tissue-engineering, we selected three typical models (Acropora sp., Goniopora sp., and Porites sp.) to analyze for pore size, porosity, permeability, and mechanical strength. We found Goniopora and Porites had homogenous structure and Acropora had oriented pores and irregular pore size. Acropora had the largest permeability, however, the transverse section was closed and the useful size was limited because of its habitat type. Porites had the smallest pore size and had the lowest permeability. Our data indicated that Goniopora sp. can be considered as the most promising source of scaffolds for bone-tissue engineering because of its high porosity (73%) and that its permeability and mechanics were similar to those in human cancellous bone. In conclusion, we analyzed the impact of the macroporous structure of coral on the permeability and mechanical properties that provide indicators for designing the optimal scaffold for bone-tissue engineering.

Is there a role of coral bone substitutes in bone repair?

“…It is characteristic that the compressive strength of corals could be as low as 2.62MPa when the one of bone is between 131 and 283 MPa. 13 In this context, FDA has issued warnings for one of the commercially available corals. 91 Briefly the Pro Osteon™ use is contraindicated in segmental defects, fracture of the growth plate, in patients with systemic or metabolic disorders affecting bone healing, in vascularly impaired bone, in infected sites or in cases when soft tissue coverage is not possible and finally cases where stabilization of the fracture cannot be attained.…”

“…Furthermore, some authors highlighted the negative effect or even complete cessation of the overall calcification that the rising water temperature and acidity has on these corals. 13,93,94 In addition, a substantial decrease in the coral reefs has been noted since 1990 and it is expected that approximately 50% of the reefs will be destroyed by 2030. 13 These data add to the overall uncertainty when planning to explore the utilization of the corals further.…”

“…have a bimodal pore size and a strongly disordered structure. 12,13 Acropora have oriented pores, irregular pore size and the largest permeability compared to Goniopora and Porites sp. 13 Their transverse section however, was closed and the useful size was limited because of its habitat type.…”

“…12,13 Acropora have oriented pores, irregular pore size and the largest permeability compared to Goniopora and Porites sp. 13 Their transverse section however, was closed and the useful size was limited because of its habitat type. 13 Porites had the smallest pore size and had the lowest permeability.…”

“…13 Their transverse section however, was closed and the useful size was limited because of its habitat type. 13 Porites had the smallest pore size and had the lowest permeability. Other coral genera have been previously investigated but with very limited use.…”