Bone regeneration hydroxyapatite composites

On the other hand, the G5 particles react with SBF, giving rise to a globular CaP amorphous structure (see Fig. 3) that emerges in the composite material (manuscript submitted), with a Ca/P ratio close to 1.5. This CaP precipitate could enhance the interaction between the bone cells and the material during bone regeneration since this amorphous CaP is a transient structure to hydroxyapatite, which is the mineral phase of bone with a higher Ca/P ratio. 

Watanabe, J., Kashii, M., Hirao, M., Oka, K., Sugamoto, K., Yoshikawa, H. Akashi, M. (2007) Quick-forming hydroxyapatite/agarose gel composites induce bone regeneration. J Biomed Mater Res A, 83, 845-52. 

An instrumental characterization of nano-hydroxyapatite was provided by Chen et al. (2002) the size of their particles was ca. 20-30 nm in width and 50-60 nm in length, with a specific surface area of 73 m /g aggregation was avoided with the use of n-butanol. The uniform dispersion of these particles in chitosan solutions was recognized as an important motif for the innovative preparation of chitosan composites in fact, nano-hydroxyapatite + chitosan composite membranes prepared by solvent casting and evaporation were found suitable for guided bone regeneration. 

In the short lapse of a few years, the research works on bone regeneration with the aid of bone cements have become more refined in terms of the effects of novel chitosan scaffolds on the cells involved in the healing process. The use of nano-hydroxyapatite as well as other inorganics in conjunction with variously modified chitosans is greatly contributing to the advancement of chitosan composites for bone healing. 

Teng, SH., Lee, EJ., Yoon, BH., Shin, DS., Kim, HE., Oh, JS. 2009. Chitosan/nano-hydroxyapatite composite membranes via dynamic filtration for guided bone regeneration. Journal of Biomedical Materials Research 88A 569-580. 

Causa F, Netti PA, Ambrosio L et al (2006) Poly-E-caprolactone/hydroxyapatite composites for bone regeneration in vitro characterization and human osteoblast response. J Biomed Mater Res 76A 151-162... 

Adapted from Tayton E, Purcell M, Aarvold A, Smith J, Briscoe A, Kancder J, et al. A comparison of polymer and polymer-hydroxyapatite composite tissue engineered scaffolds for use in bone regeneration. An in vitro and in vivo study. Journal of Biomedical Materials Research Part A 2014 102 2613-24, with permission. Copyright Wiley, 2013. 

Danoux, C.B., Barbieri, D., Yuan, H., de Bruijn, J.D., Van Blitterswijk, C.A., Habibovic, P., 2014. In vitro and in vivo bioactivity assessment of a polylactic acid/hydroxyapatite composite for bone regeneration. Biomatter 4, e27664. 

Reves, B.T., Jennings, J.A., Bumgardner, J.D., Haggard, W.O., 2012. Preparation and functional assessment of composite chitosan-nano-hydroxyapatite scaffolds for bone regeneration. Journal of Functional Biomaterials 3 (1), 114—130. 

KHlion, J., et al., 2014a. Fabrication and in vitro biological evaluation of photopolymerisable hydroxyapatite hydrogel composites for bone regeneration. J. Biomater. Appl. 28 (8), 1274-1283. Available at http //www.ncbi.nhn.nih.gov/pubmed/24114559. 

Formation of useful materials from polyphosphazenes is an important aspect of their utility. For example, a report discussed that phosphazene mixed in a 1 1 ratio with the ethyl ester of glycylglycine and 4-phenylphenol could be electrospun as a composite with poly(lactide-co-glycolide) into fiberous materials that may promote bone regeneration. Other polymers that have shown promise for orthopaedic application include amino acid substituted materials with phenolic residues (67 and 68). These materials were used to form biodegradable phosphazene-calcium-defident hydroxyapatite composites. Microparticles, on the order of 2 pm, have been formed from poly[(glycine ethyl ester)-(phenylalanine ethyl ester)phos-phazene] (69) using electrohydrodynamic atomization. Mechanisms for formation of the particles was discussed in an associated paper. ... 

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