Biomedical Engineering Reference
In-Depth Information
Protein
HPO
2-
Cl
-
Cl
-
Ca
2+
Ca
2+
Cl
-
Cl
-
HPO
2-
Ca
2+
Ca
2+
Mg
2+
HPO
2-
Mg
2+
Mg
2+
M
x+
M
x+
Na
+
Ca
2+
CO
2-
Ca
2+
Ca
2+
Na
+
HPO
2-
CO
2-
Ca
2+
FIGURE 5.2
Schematic process of biomineralization of biological hydroxyapatite in simulated body fluid
containing proteins.
Body Fluid
Cl
-
Mg
2+
Cl
-
Mg
2+
Cl
-
Na
+
Na
+
Na
+
Ca
2+
Ca
2+
Ca
2+
HPO
4
2-
HCO
3
-
HPO
4
2-
HCO
3
-
HPO
4
2-
K
+
HCO
3
-
K
+
K
+
1
2
3
Si
4+
Si
4+
OH
-
+ H
3
O
+
O
O
Na
+
O
HO
OH
HO
OH
HO
OH
OH
HO
Na
+
Si
Si
Si
Si
Si
Si
O
O
O
O
O
O
O
O
O
O
O
O
O
Ca
2+
Na
+
Ca
2+
Ca
2+
Ca
2+
Si
Si
Si
Si
Si
Si
O
O
O
O
O
O
O
O
O
Silicate-Based Ceramic
1. Rapid diffusion-controlled ion exchange of network modifying Ca
2+
and/or Na
+
ions from
the ceramic with H
3
O
+
ions from the body fluid and silanol groups (Si-OH) at the surface
form.
2. HPO
4
2-
and Ca
2+
ions from the body fluid are incorporated into the silicate layer from
an amorphous calcium phosphate layer (nucleation).
3. Crystallization and growth into biological hydroxyapatite.
FIGURE 5.3
Schematic of the mechanism of formation of calcium phosphate on the surface of silicate based
ceramics.
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