2. Bone substitute materials Surface modifications
S.M.Fatemi , DDS, PhD Tehran Medical Sciences Branch Iranian Academic Centre of Education, Culture and Research

3. Introduction Biomaterials : Bio-inert, Bioactive, Biodegradable
Bulk characteristics : mechanical
Surface characteristics: topography, surface energy, wettability, hydrophilicity

4. Surface Treatment of Biomaterials
Radiation Grafting and Photo Grafting :Strilization, Photo polymerization
Plasma Surface Modification : glow discharge plasma, ions, electrons , radicals, metastables …

5. Surface Treatment of Biomaterials
Ion Beam Processing : 1-10 million volt
Better hardness, toughness, less corrosion ….

6. Surface Treatment of Biomaterials
Silanization
Self-Assembled Monolayers
Additives and Coatings

7. LASERs chemical cleanliness
controlled thermal penetration and distortion
controlled thermal profile and, therefore, shape and location of the heat affected region
less after-machining is required
remote noncontact processing is usually possible
relatively easy to automate.

8. LASER surface modification
Both organic and inorganic materials
pulsed (100 nanoseconds to picoseconds pulse times) and continuous wave (CW)
interaction times often less than 1 microsecond.
surface alterations include annealing, etching, deposition and polymerisation

9. Laser Surface Treatment
Laser patterning and micro fabrication
Pulsed laser deposition (PLD) of biocompatible ceramics
Matrix-assisted pulsed laser evaporation (MAPLE) and MAPLE direct
write (MDW)
Laser surface treatment for improving corrosion
Laser grafting
Laser treatment of plasma sprayed HA coatings

10. LASER surface modification
Laser Patterning : photolithography, cell adhesion

11. LASER surface modification
Pulsed Laser Deposition (PLD)
Biocompatible Ceramics , CNT

12. LASER surface modification
Matrix-Assisted Pulsed Laser Evaporation (MAPLE)

13. LASER surface modification
MAPLE Direct Write : ribbon : 10 micron

14. LASER surface modification
Laser Grafting :improved surface hydrophilicity and biocompatibility
Laser bio printing
Selective laser melting: dental implants

15. Gamma Ray Electromagnetic Radiation Extremely High Frequency
High Energy: Ionizing Radiation
Frequencies > 1019Hz
Energies above 100 keV
Wavelengths less than 10 picometers
less than the diameter of an atom!

16. Effect of Gamma Ray on Materials
Reduction of molecular weights of polymers
Radical Production and chain scissoring
Higher doses > cross-linking
Increase in enthalpy in bioceramics
Biocompatibility , bioactivity ,Bio-conductivity, and absorption

17. Synthesis and characterization
Hydroxyapatite
common wet chemical method
[Ca(NO3)2 +4 H2O]
[(NH4)2HPO4]
Ca/P ratio of 1.67 h K ℓ
2θ ICDD HAp
Peak
Intensity %
2θ Synthesized HAp 2
25.879 40
25.893
36.90 1
31.773
100
31.698
32.196 60
32.351
69.43 3
32.902
32.914
63.10
34.048 25
34.169
23.81
39.818 20
39.978
21.43
46.711 30
46.783
32.14
49.468
49.409
40.48
50.493
50.448
22.62 4
53.143
53.173

18. Hydroxyapatite
DSC increase its enthalpy

19. Hydroxyapatite Wettability and contact angle Material
Non-irradiated samples
25KGy irradiated samples
50KGy irradiated samples
Hydroxyapatite
26.16 º ± 2.51 º
20.35 º ±1.35 º
12.62 º ±1.4 º

20. Hydroxyapatite Cell viability (MTT Assay) and Cell Toxicity
More viable cells via decrease in crystallite size
Material
Non-irradiated
samples
25KGy irradiated samples
50KGy irradiated samples
Day3
Day7
Day 14
Day 21
hydroxyapatite
47.7±4.66
40.79±10.66
39.43±1.23
159.73±43.4
64.3±12.8
49.42±7.08
71±15.2
95.33±0618
47.28±2
60.77±3.55
65.4±12
143.33±30.6

21. Hydroxyapatite Cell viability (MTT Assay) and Cell Toxicity 7th Day
21st Day

22. Cell viability (MTT Assay) and ALP activity
Control Group
Cell viability (MTT Assay) and ALP activity

23. Hydroxyapatite Alkaline phosphatase activity
Less alkaline phosphatase activity
Material
Non-irradiated
25KGy irradiation
50KGy irradiation
Day 7
Day 14
Day 21
Day21
Hydroxyapatite
99.22±4.52
130.2±19.88
125.14±27.5
87±12.25
105.58±8.54
126.94±38.7
77.77±3.6
113.72±1.7
125±23.19

24. Thanks for your attention