Improvement of the compressive strength of a cuttlefish bone‐derived porous hydroxyapatite scaffold via polycaprolactone coating

Abstract

Cuttlefish bones (CBs) have emerged as attractive biomaterials because of their porous structure and components that can be converted into hydroxyapatite (HAp) via a hydrothermal reaction. However, their brittleness and low strength restrict their application in bone tissue engineering. Therefore, to improve the compressive strength of the scaffold following hydrothermal conversion to a HAp form of CB (CB-HAp), the scaffold was coated using a polycaprolactone (PCL) polymer at various concentrations. In this study, raw CB was successfully converted into HAp via a hydrothermal reaction. We then evaluated their surface properties and composition by scanning electron microscopy and X-ray diffraction analysis. The CB-HAp coated with PCL showed improved compressive performance and retained a microporous structure. The compressive strength was significantly increased upon coating with 5 and 10% PCL, by 2.09-and 3.30-fold, respectively, as compared with uncoated CB-HAp. However, coating with 10% PCL resulted in a reduction in porosity. Furthermore, an in vitro biological evaluation demonstrated that MG-63 cells adhered well, proliferated and were able to be differentiated on the PCL-coated CB-HAp scaffold, which was noncytotoxic. These results suggest that a simple coating method is useful to improve the compressive strength of CB-HAp for bone tissue engineering applications.

Synthetic and Marine-Derived Porous Bone Graft Substitutes

“…The compressive strength decreased with the HT due to a more extensive degradation of the organic matter that provides the mechanical support of the structure, however, with exception of the coating with 1% PCL, the compressive strength improved with the PCL coating as reported in Table 2. The coated scaffolds did not exhibit any cytotoxicity, cells were able to adhere and proliferate and also it was demonstrated that penetration of cell happened through the entire depth of the scaffold [206,209]. The cell proliferation was higher for the sample coated with 1% PCL.…”

“…Composite materials derived from CB CaP scaffolds obtained from CB are normally brittle and exhibited low strength, thereby limiting the application of these materials as bone grafts. In order to improve the compressive strength, some authors investigated the coating of these scaffolds with polymers like PCL [206][207][208][209], polyvinyl alcohol [207] and collagen [210].…”

“…CBHA scaffolds were obtained through a HT and PCL was incorporated into the scaffold structure under vacuum to remove the air from the pores and allow a complete impregnation of the polymer into the structure [206][207][208][209]. Kim et al [206] reported the coating with 1, 5, and 10% of PCL of CBHA scaffolds.…”

“…Kim et al [206] reported the coating with 1, 5, and 10% of PCL of CBHA scaffolds. The PCL layer obtained by the coating with 1% PCL could be hardly observed and the roughness of the sample was similar to the uncoated one.…”

“…Coating with 5% PCL led to the formation of a thin PCL layer that covered the entire surface. With further increasing the amount of PCL to 10%, a thicker layer was formed and the number of clogged pores increased, thereby decreasing the porosity [206]. Nonetheless, Milovac et al [208] coated the scaffolds with 20% PCL, and although roughness and porosity have noticeably decreased, they reported that such a coating allowed the maintenance of the number of pores and their interconnectivity [208].…”