Interfacial and biological properties of the gradient coating on polyamide substrate for bone substitute

Abstract

Fabrication of bioactive and mechanical matched bone substitutes is crucial for clinical application in bone defects repair. In this study, nano-hydroxyapatite/ polyamide (nHA/PA) composite was coated on injection-moulded PA by a chemical corrosion and phase-inversion technique. The shear strength, gradient composition and pore structure of the bioactive coating were characterized. Osteoblast-like MG63 cells were cultured on pure PA and composite-coated PA samples. The cells' adhesion, spread and proliferation were determined using MTT assay and microscopy. The results confirm that the samples with the nHA/PA composite coating have better cytocompatibility and have no negative effects on cells. To investigate the in vivo biocompatibility, both pure PA and composite-coated PA cylinders were implanted in the trochlea of rabbit femurs and studied histologically, and the bonding ability with bone were determined using push-out tests. The results show that composite-coated implants exhibit better biocompatibility and the shear strength of the composite-coated implants with host bone at 12 weeks can reach 3.49 + 0.42 MPa, which is significantly higher than that of pure PA implants. These results indicate that composite-coated PA implants have excellent biocompatibility and bonding abilities with host bone and they have the potential to be applied in repair of bone defects.

In vivo performance of Al2O3-Ti bone implants in the rat femur

“…Several studies measured the shear strength/modulus of the bone bond with different implant materials through the push-out test and obtained higher bond strength by the time. For example, Huang et al [ 40 ] tested the in vivo performance of two implant materials in a rabbit model. Their push-out test showed higher shear strength for both materials at week 12 compared to week 4.…”

Aligned hydroxyapatite nano-crystal formation on a polyamide surface

“…29 It means that the calciumethanol complex molecules open the hydrogen bonding between the polymer chains. 23 As a result, the polymer chains at the surface of the substrate become loose and complex with calcium ions. 23,27 The increased peak at 1024 cm À1 corresponding to the C]O groups in Fig.…”

“…23 As a result, the polymer chains at the surface of the substrate become loose and complex with calcium ions. 23,27 The increased peak at 1024 cm À1 corresponding to the C]O groups in Fig. 2 verify this point.…”

“…Owning to its similarity to collagen protein in chemical structure and active groups (for example, -C]O-NHgroups), PA has already been proved to possess good biocompatibility with various human cells and tissues and widely used in biomaterials application. [23][24][25][26] Pre-treated PA lamina can provide a collagen-like organic matrix by chelating calcium ions on carbonyl groups of the amide chains. 27 The calcium-rich microenvironment serves as a dynamic nucleation scaffold that controls and facilitates the formation of highly ordered, elongated apatite crystals.…”

Nylon—A material introduction and overview for biomedical applications

“…To enhance the physicochemical and biological properties of nylon 6 scaffolds, a calcium phosphate ultrathin layer was coated on the electrospun scaffolds resulted in a desirable nanocomposite for bone tissue regeneration 87 . Animal model studies using nano HA/nylon composite implant were also conducted, and the results demonstrated good contact between the bone and implant 88 . Besides calcium phosphate‐based materials, a study took advantage of a calcium zirconium silicate mineral called baghdadite to be concocted with nylon 6 for bone tissue regeneration 89 .…”