Nanocrystalline Hydroxyapatite

1
Nanocrystalline Hydroxyapatite
Fundamentals of Nanotechnology

• Cornelia Cretiu Vasiliu
• 12-01-2007

2
Outline

• Motivation
• Methods of synthesis
• Characterization of structure
• Morphology and particle size
  distribution
  
  
• Properties
  Applications

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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(PO
  4)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
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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
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nHA Methods of synthesis

• Co precipitation
  1)
• Ca(OH)2 H3 PO4 nHA
• Aqueous, pH 8, 38oC
• Microwave synthesis 2)
• 10 Ca(OH)26 (NH4)2HPO4
  Ca10(PO4)6(OH)26H2O12NH4OH
• 850W, 20 min.
• 13)Aq. Sol. NaNO3, Ca(NO3)24H2O and KH2PO4
  precursor
• 600W, 5 min.
• stirred in H2O ( room temperature , 1 h) nHA
  particles.

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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) ß-TCP (a) a-TCP.( 1
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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.

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Particles morphology
SEM micrograph of the as-prepared nHA(1
TEM micrograph of as-synthesized nano HA
crystals(14
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Particle size distribution

• DLS Histogram representation of the mean
  diameters of as-prepared nHA suspended in aqueous
  solution. (1

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Applications
Coatings

• Cell morphology after being cultured for 15 min
  on the different nHA coated(G2) and uncoated(G1H)
  titanium surfaces.
• Surface roughness decreased(2

(2
Fibers, tubes

• nHA doped PLGA composite (30 nHA) hollow fiber
  membrane fabricated using wet phase inversion
  technique (13

(13
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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.

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

1. http//www.sciencedirect.com/science/article/B6THV
   -4JVK567-1/2/501b2d84c7d81d8e9dc5771941065db1
   Phase
2. Xiaolong Zhu et al 2006 Nanotechnology 17
   2711-2721  
3. http//www.sciencedirect.com/science/article/B6TWH
   -4KY88TT-3/2/2a01537a8d0b528852bb67f079d7e91a
   Rapid densification
4. 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.
5. C. Liu, Y. Huang, W. Shen and J. Cui,
   Biomaterials 22 (2001), pp. 301306.
6. X. Yang and Z. Wang, J. Mater. Chem. 8 (1998),
   pp. 22332237
7. W. Feng, L. Mu-sen, L. Yu-peng and Q. Yong-xin,
   Mater. Lett. 59 (2005), pp. 916919
8. S.K. Yen and C.M. Lin, Mater. Chem. Phys. 77
   (2003), pp. 7076.
9. K. Itatani, T. Nishioka, S. Seike, F.S. Howell,
   A. Kishioka and M. Kinoshita, J. Am. Ceram. Soc.
   77 (1994), pp. 801805
10. C.-W. Chen, R.E. Riman, K.S. TenHuisen and K.
    Brown, J. Cryst. Growth 270 (2004), pp. 615623
11. G.Z. Hui, Z. Qingshan and H.X. Zhao, Mater. Res.
    Bull. 40 (2005) (8), pp. 13261334.
12. W.L. Suchanek, K. Byrappa, P. Shuk, R.E. Riman,
    V.F. Janas and K.S. TenHuisen, J. Solid State
    Chem. 177 (2004), pp. 793799
13. N. Zhang et al. / Materials Science and
    Engineering C 27 (2007) 599606
14. S. Ramesh et al. / Ceramics International 33
    (2007) 13631367

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Questions?
HAßTCP 6040 1100oC/4h
HAßTCP 6040 1270oC/4h