Nanocrystalline calcium phosphates

Spherical shape, consisting of nanocrystalline calcium phosphate or ceramic diamond covered with a polyhydroxylated oligomeric film. Drugs and antigens are adsorbed onto the particle surface. 

Chesnutt BM, Viano AM, Yuan Y (2009) Design and characterization of a novel chitosan/ nanocrystalline calcium phosphate composite scaffold for bone regeneration. J Biomed Mater Res 88A 491-502... 

Madou M. Fundamentals of microfabrication the science of miniaturization. CRC 2002. Arul KT, et al. Novel ultraviolet emitting low energy nitrogen ion implanted magnesium ion incorporated nanocrystalline calcium phosphate. Mater Lett 2015 153 182-5. 

Kalita SJ, Bhardwaj A, Bhatt HA. Nanocrystalline calcium phosphate ceramics in biomedical engineering. Mater Sci Eng C 2007 27 441-9. 

It might be argued that the results by Jager et al. (2006) discussed and interpreted earlier pertain only to nanocrystalline hydroxyapatite synthesised from an aqueous solution. However, they are clearly relevant to calcium phosphate biomimetically precipitated from SBFs used to validate the degree of osseoconductivity of bioceramic coatings. 

Ievlev, V.M., Kostyuchenko, A.V., Darinskii, B.M., and Barinov, S.M. (2014) Hardness and microplasticity of nanocrystalline and amorphous calcium phosphate coatings. Phys. Solid State, 56 (2), 321-329. 

Bone is a natural composite comprised of type I collagen and calcium phosphate minerals, of which nanocrystalline apatite is the main component [39, 40]. Certain osteoconductive bioceramics exert an effect on bone cell attachment and growth factor binding or release, and can accelerate the treatment of bone defects [41-43]. Polymer composite scaffolds can be produced, via electrospinning, which contain a specific amount of electrical charge in order to form non-woven fibrous meshes with fibre dimensions in the nano- to microscale [44-46]. 

Mobasherpour L, Heshajin M. (2007). Synthesis of nanocrystalline hydroxyapatite by using precipitation method. Journal cf Alloys and Compounds, N 430, pp. 330 - 333 Nilen R.W.N., Richter P.W. (2008). The thermal stability of hydroxyapatite in biphasic calcium phosphate ceramics. J. Mater. Sci Mater. Med., Vol. 19(4), pp. 1693-1702 Ratner B., Hoffman A., Schoen F. et. al. (2004). Biomaterials Scienc. An Introduction to Materials in Medicine, Second Edition / / Academic Press, pp. 851 Raynaud S., Champion E., Bemache-Assollant D. Et al. (2002). Calcium phosphate apatite with variable Ca/P atomic ratio L Synthesis, characterisation and thermal stability of powders. Biomaterials No 23, pp. 1065-1072 Shi D., (2006). Introduction to biomaterials. World Scientific Publishing, p. 253. 

Zhang F, Lin K, Chang J, Lu J, Ning C. Spark plasma sintering of macroporous calcium phosphate scaffolds from nanocrystalline powders. J Eur Ceram Soc 2008 28 539-45. 

DNase, a well characterized and biologically specific enzyme with therapeutic value in the treatment of cystic fibrosis, was chosen as a model agent for studying the effects on an enzymatic bio/molecule of surface immobilization on nanocrystalline ceramic particulates. As the data show, and consistent with previous observations, DNase exhibits a marked retention of biological activity when surface immobilized on the solid phase of a colloid comprised of polyhydroxyl oligomeric films investing degradable calcium-phosphate nanoparticles. 

Isothermal calorimetry results (37.4°C) are shown in Fig. 32. A two-step reaction mechanism was proposed. The first peak is associated with consumption of all the brushite and some tetracalcium phosphate in the formation of noncrystalline calcium phosphate and nanocrystalline hydroxyapatite. The second peak is associated with the consumption of the remaining tetracalcium phosphate and the calcium phosphate intermediate. 

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