Microstructural disassembly of calcium phosphates

Abstract

Abstract:Microstructural factors may play a role in the osseointegration of calcium phosphates. In this paper, direct microstructural interactions between crystalline calcium phosphates and the biological milieu are reported. Degradation via exposure to osteoblast culture closely resembles in vivo interactions with subcutaneous tissues in a bovine model at early time periods. That these interactions were common to both experiments constitutes one of the few known examples of in vitro-in vivo correspondence. Interestingly, the degradation of phase pure hydroxyapatite (HA) in vitro was more rapid than that of biphasic HA in vivo. In both cases, grain extraction/pullout was frequently observed. This suggests a connection to smaller-scale observations of epitaxial CHA nucleation and growth on pre-existing HA grains. A microstructure in which the grain boundary is dissolving/corroding can apparently be disassembled by forces transmitted through biological structures. These observations are distinct from those of simple non-biological solutions and prove that biological environments can interact with the material beneath the ceramic-cell/ceramic-tissue interface. Many often ignored microstructural factorsgrain size, shape, grain boundary strength and the presence of impurity phases-may in fact control degradation. We also suggest that even relatively modest initial grain sizes will, in combination with the mild/absent foreign body response to calcium phosphates, result in lengthy in vivo particle resistence.

Dissolution of Human Teeth-Derived Hydroxyapatite

“…3,4 numerous studies have confirmed microstructural degradation of materials during exposure to the in vitro and in vivo environment. 6,7,9,10,20,33,51,52 Numerous problems have been reported when HA is under degradation. There would be little mechanical interlocking of biological tissues with the HA implanted.…”

Mechanism of Surface Dissolution in Dense Hydroxyapatite

“…Hydroxyapatite [Ca 10 (PO 4 ) 6 (OH) 2 , HA] has achieved significant application as a bone graft material in a range of orthopedic and dental applications due to its chemical and crystallographic structure being similar to that of bone mineral [1][2][3][4][5]. However, the mechanical properties like fracture toughness of HA ceramics can be drastically decreased by body fluid causing particle loosening and microstructural degradation of materials when implanted in body [3,[6][7][8].…”

Amphiphilic Thiol Functional Linker Mediated Sustainable Anti-Biofouling Ultrafiltration Nanocomposite Comprising a Silver Nanoparticles and Poly(vinylidene fluoride) Membrane

“…The bacteria that adhered to the membrane were observed by FE-SEM imaging. Prior to FE-SEM observation, the bacteria adhered to the membrane were fixed in a 4% (v/v) glutaraldehyde solution, 36 and the resulting membranes were dehydrated with ethanol and dried at room temperature.…”