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Andreece Richardson

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					  Hydroxyapatite Coatings by
   Pulsed Laser Deposition
A pathway for improving the performance of
      orthopedic and dental implants

            Andreece Richardson
             Department of Physics
      University of Alabama at Birmingham
Orthopedic and Dental Implants
             Typically made of Titanium Alloys
               Good corrosion and fatigue life
               Acceptable biocompatibility

             Deposition of a coating of a
              material known as Hydroxyapatite
              on titanium implants
               Improves bioactivity
               Improves biocompatibility

              Hydroxyapatite is an important
              component of human bone!
         What type of material is
           Hydroxyapatite?
 Ceramic material
 Main mineral constituent of bone and teeth
 Bone and teeth
    – 50 wt.% mineral
       (mainly Hydroxyapatite)
    – 50 wt.% organic molecules + water
       (collagen, mucopolysaccharides) and water
A great way of depositing Hydroxyapatite:
         Pulsed Laser Deposition

                                        Substrate


                         Vacuum
                         chamber                Gaseous plume

     Excimer laser

                                                    Target



                     UV-transparent window
    Pulsed Laser Deposition is a
         Great Technique
 Versatile technique for preparing a wide range of
  thin films and multi-layer structures
 Can work under controlled gas ambient
 Allows deposition of different coatings by
  changing the parameters of deposition
 Gives researchers the opportunity to discover
  novel coatings with long-term stability
Pulsed Laser Deposition
Mixed Argon and Water
      Pathway
       Deposition Experiments
Sam      Laser    Rep.   Ambient    Sub.   Target-Sub.
 ple    Fluence   Rate   (mTorr)   Temp.    Distance
        (J/cm2)   (Hz)              (C)      (cm)
#1        10      30       200      600        4.9
                         Ar/H2O*
#2        4       30       300      600        7.5
                         Ar/H2O*
#3        4       30       300      550        7.5
                         Ar/H2O*
#4        4       30       300      500        7.5
                         Ar/H2O*
#5        4       30       500      600        7.5
                         Ar/H2O*
                            *
            X-Ray Diffraction Results
Besides Hydroxyapatite
#5: 500 mTorr; Water at 50 °C
          (Ca5(PO
Substrate: 600°C 4)3(OH))
There are other                                               Sample #5
Calcium Phosphate Ceramics:
 #4: 300 mTorr; Water at RT
 - Tricalcium phosphate                                       Sample #4




                                Intensity (arb. units)
 Substrate: 500°C ) )
             (Ca3(PO4 2                                       Sample #3
 - Tetracalcium phosphate                                                                  *
 #3: 300 mTorr; Water) at RT
             (Ca4P2O9                                         Sample #2
 Substrate: 550°C
 - Amorphous hydroxyapatite                                                                *

                                                              Sample #1
 #2: 300 mTorr; Water at RT
                                                                                                (211) (112)
 Substrate: 600°C                                                          (002)      (210)               (300)
                                                              HA target
                                                                                   (102)                  (202)

 #1: 200 mTorr; Water at RT
 Substrate: 600°C                                        20               25               30                     35
                                                                               2Theta
          Conclusion
 We have found good conditions for
depositing Hydroxyapatite by Pulsed
         Laser Deposition:

   500 mTorr Ar/Water; Water at 50 °C
           Substrate: 600°C
           Acknowledgments


Thanks to Two Outstanding Mentors
   Hyunbin Kim and Dr. Renato
            Camata!

				
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