Dramatic Improvement of the Mechanical Strength of Silane-Modified Hydroxyapatite–Gelatin Composites via Processing with Cosolvent

Abstract

Bone tissue engineering (BTE) requires a sturdy biomaterial for scaffolds for restoration of large bone defects. Ideally, the scaffold should have a mechanical strength comparable to the natural bone in the implanted site. We show that adding cosolvent during the processing of our previously developed composite of hydroxyapatite–gelatin with a silane cross-linker can significantly affect its mechanical strength. When processed with tetrahydrofuran (THF) as the cosolvent, the new hydroxyapatite–gelatin composite can demonstrate almost twice the compressive strength (97 vs 195 MPa) and biaxial flexural strength (222 vs 431 MPa) of the previously developed hydroxyapatite–gelatin composite (i.e., processed without THF), respectively. We further confirm that this mechanical strength improvement is due to the improved morphology of both the enTMOS network and the composite. Furthermore, the addition of cosolvents does not appear to negatively impact the cell viability. Finally, the porous scaffold can be easily fabricated, and its compressive strength is around 11 MPa under dry conditions. All these results indicate that this new hydroxyapatite–gelatin composite is a promising material for BTE application.

Bovine hydroxyapatite-based scaffold accelerated the inflammatory phase and bone growth in rats with bone defect

“…This complex subsequently interacts with the PO 4 3- and forms critical size nuclei, which are useful for HA crystal formation. 24,25 Moreover, the compressive strength of the BHA-GEL scaffold is the closest to that of the human cortical bone (100–230 MPa), and slightly higer than the human bone tensile strength reported by Fischer et al 39 This compressive strength of BHA-GEL was also the closest to the rat femur bone, which was reported as 126.6 ± 19.7 and 167.3 ± 42.2 MPa for metaphyseal and diaphyseal specimens, respectively. 37 These hard characteristics of BHA-GEL scaffolds may prevent the premature degradation of the scaffold in vivo.…”

“…In this study, BHA/HA was formulated with gelatin (GEL) as the bone scaffold. 3,[24][25][26] The addition of GEL helps in increased the compressive strength of biomaterials, In general, the addition of polymers such as gelatine (GEL) helped increase the compressive strength and resulted in a controllable degradation rate of the scaffold. 27,28 The aim of this study was to investigate the in vivo performance of the BHA-based scaffold, specifically inflammatory response through M1 and M2, and osteoconductivity.…”