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Nanocrystalline Hydroxyapatite

Fundamentals of Nanotechnology. Nanocrystalline Hydroxyapatite. Cornelia Cretiu Vasiliu 12-01-2007. Outline. M otivation M ethods of synthesis C haracterization of structure

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Nanocrystalline Hydroxyapatite

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  1. Fundamentals of Nanotechnology Nanocrystalline Hydroxyapatite Cornelia Cretiu Vasiliu 12-01-2007

  2. Outline Motivation Methods of synthesis Characterization of structure Morphology and particle size distribution Properties & Applications

  3. Why nano-Hydroxyapatite (nHA) • Bone: 2nd most implanted tissue after blood • Protein matrix containing type 1 collagen and minerals • Calcium as: (Ca 2+)10-x(H3O+)2x*(PO4)6(OH-)2 • Synthetic vs. homo-, allo-, xeno-geneic implants • Properties: biocompatibility, biodegradability, mechanical integrity, vascularization inductivity, osteoconductivity, and osteoinductivity http://www.uabhealth.org/16313

  4. Methods of synthesis HA Wet methods5 Solid-state reactions6 Sol-gel7 Ellectrocrystallization8 Spray pyrolysis9 Emulsion processing10 Hydrothermal treatment11 nHA Chemical precipitation1 Hydrothermal treatment12 Microwave synthesis2 To be considered: stoichiometry, pH, rate of addition, ionic strength

  5. nHA Methods of synthesis • Co precipitation 1) • Ca(OH)2 + H3 PO4 nHA • Aqueous, pH 8, 38oC • Microwave synthesis 2) • 10 Ca(OH)2+6 (NH4)2HPO4 Ca10(PO4)6(OH)2+6H2O+12NH4OH • 850W, 20 min. • 13)Aq. Sol. NaNO3, Ca(NO3)2·4H2O and KH2PO4 precursor • 600W, 5 min. • stirred in H2O ( room temperature , 1 h) nHA particles.

  6. Structure characterization • XRD(1 Powder XRD of the HA precipitate: (a) as-prepared, (b) calcined at 700 °C, (c) calcined at 800 °C, (d) calcined at 900 °C and (e) calcined at 1200 °C. [specific peaks :(H) HAP; (b) β-TCP; (a) α-TCP].( 1

  7. Structure characterization (2) IR(1 spectra of the nHA precipitates: • (a) as-dried, • (b) calcined at 700 °C, • (c) calcined at 800 °C, • (d) calcined at 900 °C and • (e) calcined at 1200 °C.

  8. Particles morphology SEM micrograph of the as-prepared nHA(1 TEM micrograph of as-synthesized nano HA crystals(14

  9. Particle size distribution • DLS: Histogram representation of the mean diameters of as-prepared nHA suspended in aqueous solution. (1

  10. Applications Cell morphology after being cultured for 15 min on the different nHA coated(G2) and uncoated(G1H) titanium surfaces. Surface roughness decreased(2 nHA doped PLGA composite (30% nHA) hollow fiber membrane fabricated using wet phase inversion technique (13 Coatings (2 Fibers, tubes (13

  11. Applications • Bone filler(4 • Preoperative axial CT • (B) Lateral preoperative view • (C) After reduction, the remaining defect was filled with nHA paste. • (D) Postoperative radiograph • (E) 6 weeks after surgery . The patient progressed to full weight bearing at this point in time. • (F) 12 months postoperatively, only a marginal loss of correction could be measured.

  12. Future developments CT scan Computer file Choose customized design Print, sinter implant Seed cells, growth factors Implant

  13. References • http://www.sciencedirect.com/science/article/B6THV-4JVK567-1/2/501b2d84c7d81d8e9dc5771941065db1 Phase • Xiaolong Zhu et al 2006 Nanotechnology17 2711-2721   • http://www.sciencedirect.com/science/article/B6TWH-4KY88TT-3/2/2a01537a8d0b528852bb67f079d7e91a Rapid densification • F. Huber, J. Hillmeier, N. McArthur, H. Kock and P. J. Meeder, The Use of Nanocrystalline Hydroxyapatite for the Reconstruction of Calcaneal Fractures: Preliminary Results, J. of Foot and Ankle Surgery Vol. 45/ 5, 2006, pp. 322-328. • C. Liu, Y. Huang, W. Shen and J. Cui, Biomaterials22 (2001), pp. 301–306. • X. Yang and Z. Wang, J. Mater. Chem.8 (1998), pp. 2233–2237 • W. Feng, L. Mu-sen, L. Yu-peng and Q. Yong-xin, Mater. Lett.59 (2005), pp. 916–919 • S.K. Yen and C.M. Lin, Mater. Chem. Phys.77 (2003), pp. 70–76. • K. Itatani, T. Nishioka, S. Seike, F.S. Howell, A. Kishioka and M. Kinoshita, J. Am. Ceram. Soc.77 (1994), pp. 801–805 • C.-W. Chen, R.E. Riman, K.S. TenHuisen and K. Brown, J. Cryst. Growth270 (2004), pp. 615–623 • G.Z. Hui, Z. Qingshan and H.X. Zhao, Mater. Res. Bull.40 (2005) (8), pp. 1326–1334. • W.L. Suchanek, K. Byrappa, P. Shuk, R.E. Riman, V.F. Janas and K.S. TenHuisen, J. Solid State Chem.177 (2004), pp. 793–799 • N. Zhang et al. / Materials Science and Engineering C 27 (2007) 599–606 • S. Ramesh et al. / Ceramics International 33 (2007) 1363–1367

  14. Questions? HA:βTCP 60:40 1270oC/4h HA:βTCP 60:40 1100oC/4h

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