On Biomimetics by Lilyana Pramatarova

On Biomimetics
148

IR data also revealed a change in the carbonate content of the samples treated in SBFc and
SBFr with different carbonate content (Fig. 5). As a measure of the carbonate content we
used the ratio between the areas underneath the peaks corresponding to CO 3 2- (1549-1336
cm-1) and PO 4 3- (1280-914 cm-1) stretching bands. As can be seen, the amount of carbonate
ions faster increases in samples matured in SBFr than in those matured in SBFc.
Thermodynamic modeling of the maturation process of two different solid calcium
phosphate products - a metastable amorphous product (*ACP), and a stable equilibrium
product (**ACP) were done in the three solutions (SBFc, SBFr and SBFg) differing in their
ionic content (Table 8).

Phase

Maturation of *ACP Maturation of **ACP

SBFc SBFr SBFcg SBFc SBFr SBFcg

NaCl -3.59 -3.66 -3.59 -3.59 -3.65 -3.59

Na 2 SO 4 -6.15 -6.14 -6.16 -6.14 -6.13 -6.14

Na 2 SO 4 .10H 2 O -5.34 -5.32 -5.35 -5.33 -5.31 -5.33

NaHCO 3 -3.53 -3.17 -3.59 -3.81 -2.4 -3.54

NaHCO 3 .Na 2 CO 3 .2H 2 O -9.76 -8.69 -9.94 -12.95 -9.05 -12.04

Na 2 CO 3 .H 2 O -7.66 -6.94 -7.78 -10.56 -8.08 -9.93

Na 2 CO 3 .10H 2 O -6.25 -5.53 -6.37 -9.15 -6.67 -8.53

MgSO 4 .7H 2 O -5.26 -5.84 -5.33 -5.25 -5.25 -5.22

MgCO 3 -1.17 -1.05 -1.34 -4.07 -1.6 -3.40

MgCO 3 .3H 2 O -3.67 -3.55 -3.84 -6.56 -4.1 -5.90

Mg 3 (PO 4 ) 2 -2.27 -1.90 -2.78 -9.29 -5.77 -8.00

MgHPO 4 .3H 2 O -1.01 -0.89 -1.19 -1.91 -1.21 -1.64

Mg 3 (PO 4 ) 2 .22H 2 O -2.3 -1.93 -2.83 -9.32 -5.8 -8.06

Mg 5 (CO 3 ) 4 (OH) 2 .4H 2 O -10.95 -10.33 -11.80 -27.75 -15.76 -24.36

KMgPO 4 .6H 2 O -2.92 -2.43 -3.25 -6.43 -4.66 -5.91

Ca(OH) 2 -9.01 -9.01 -9.01 -14.34 -13.49 -14.06

CaSO 4 -2.77 -3.48 -2.66 -2.86 -4.13 -3.29

CaSO 4 .2H 2 O -2.58 -3.28 -2.48 -2.67 -3.94 -3.10

CaMg 3 (CO 3 ) 4 -3.18 -2.81 -3.69 -14.86 -6.25 -12.67

CaHPO 4 .2H 2 O -0.23 -0.23 -0.23 -1.23 -1.8 -1.42

Mg(OH) 2 -5.95 -5.93 -6.16 -11.05 -9.0 -10.47

Mg 3 (PO 4 ) 2 .8H 2 O -0.37 0 -0.89 -7.14 -3.77 -6.16

MgCO 3 .Mg(OH) 2 .3H 2 O -4.41 -4.27 -4.83 -12.29 -7.75 -11.12

CaCO 3 0 0 0 -2.94 -1.77 -2.80

CaHPO4 0 0 0 -1.05 -1.61 -1.11

Ca 3 (PO 4 ) 2 (am) 0 -0.10 0 -6.76 -7.64 -7.43

Ca 8 H 2 (PO 4 ) 6 .5H 2 O -6.62 -8.43 -7.19

Ca 9 Mg(HPO 4 )(PO 4 ) 6 -11.37 -11.55 -11.36

Ca 10 (PO 4 ) 6 (OH) 2 0 0 0

Notes: The impurities in the washed initial products were taken in the range 1-3 % based on the
measured Mg/Ca ratio (3 mol %) (Table 5).
*ACP – metastable amorphous product; **ACP – stable equilibrium product.

Table 8. Likely salts in the biomimetic systems and their thermodynamic calculated
saturated indices (SI) at biomimetic maturation.