Hydroxyapatite nanoscale

The nanostructured surfaces resemble, at least to a certain degree, the architecture of physiological adhesion substrates, such as extracellular matrix, which is composed from nanoscale proteins, and in the case of bone, also hydroxyapatite and other inorganic nanocrystals [16,17,24-27]. From this point of view, carbon nanoparticles, such as fullerenes, nanotubes and nanodiamonds, may serve as important novel building blocks for creating artificial bioinspired nanostructured surfaces for bone tissue engineering. 

Photoluminescence piezospectroscopy is an accurate measurement method to determine nanoscale stress distributions and surface defects that control device performance and reliability, that is performance over the service life of biomaterials such as hydroxyapatite coatings and implants. 

Figure 4.4 Design and fabrication of the osteophilic multilayer architecture. Components of the film (a) Chitosan (75-85% deacetylated chitin) a polycation (b) Poly(acrylic acid) (PAA) (c) A hydrolytically degradable poly(p-amino ester) (Poly2), a polycation and (d) osteoinductive recombinant human bone morphogenetic protein 2 (rhBMP-2) (e) Schematic of the modular electrostatic assembly. Osteoconductive hydroxyapatite (HAP) is complexed with chitosan and incorporated into nanoscale thick films along with poly(acrylic acid) in a bilayer architecture. A hydrolytically degradable poly(P-amino ester)-based multilayer fihn incorporating osteoinductive rhBMP-2 lays atop the osteoconductive layer, (f)...

Zhou H, Lee J. Nanoscale hydroxyapatite particles for bone tissue engineering. Acta Biomater 2011 7 2769-81. 

Bone tissue, for example, is a nanocomposite composed of rigid hydroxyapatite (HA) nanocrystals (60%) precipitated onto coUagen fibers (30%) (Figure 40.1) [1]. Hydroxyapatite, which occurs as small plates that are tens of nanometers in length and width and 2 3 run in depth, impart compressive strength to bone. Collagen fibrils (1.5 3.5 nm in diameter) form triple hehces and bundle into fibers (50-70 nm diameter) responsible for the unique tensile properties of composite bone tissue [2]. The unique and complex mechanical properties of bone tissue arise from the interaction of these two components in the nanoscale [3]. 

FIGURE 40.1 Nanocomposite structure of bone. The interaction between coiiagen fibers and HA nanocrystals in the nanoscale gives rise to the complex mechanical properties of bone tissue observed in the macroscale. Cells operating on this collagen/hydroxyapatite nanocomposite continually remodel bone on the microscale. 

Zhou, H., Lee, J., 2011. Nanoscale hydroxyapatite particles for bone tissue engineering. Acta Biomaterialia 7 (7), 2769-2781. Available at http //www.ncbi.nlm.nih.gov/ pubmed/21440094 (accessed 17.07.14.). 

Shalumon, K.T., Sowmya, S., Sathish, D., Chennazhi, K.P., Nair, S.V., Jayakumar, R., 2013. Effect of incorporation of nanoscale bioactive glass and hydroxyapatite in PCL/chitosan nanofibers for bone and periodontal tissne engineering. Journal of Biomedical Nanotechnology 9 (3), 430-440. 

This chapter presents the current trends in this area with emphasis on load-bearing orthopaedic and dental implants. A detailed account on the general and the localized corrosion of conventional metalhc implants is provided. Novel fabrication strategies of nanostructured hydroxyapatite-based coatings and their roles as barrier coatings are presented. Impacts of nanoscale surface modifications on the corrosion resistance of permanent implants and novel bioresorbable implants based on magnesium alloys are highhghted. 

The osteon is one of the fundamental funetional unit of human eortieal bone. Eaeh osteon consists of concentric lamellae, approximately 3 to 7 pm thick, arranged around a central Haversian canal. At the nanoscale level, these lamellae ate made of mineral platelets (hydroxyapatite) with given size and orientation distributions, embedded in an oiganic matrix of collagen fibers. 

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