6.4.2.3 Modified Single Crystal Silicon Template
In in vitro mineralization experiments, glass substrate is often used because of its
good characters like extensive resources, convenient usage, cheap price, etc., but
glass surface may induce aragonite crystals. Single crystal silicon is another
commonly used substrate. The single crystal silicon substrate should be treated
by HF acid to remove surface oxide layer, then cleaned by acetone, absolute ethyl
alcohol, and deionized water to expose the (100) crystal plane. (Li 2008) tentatively
studied radical influence on polymorph of calcium carbonate crystals by surface
modification with –OH, –NH 2 and –COOH on single crystal silicon substrate.
WSM and ASM were absorbed on such substrate to prepare specific templates,
and then in vitro mineralization experiments were carried out. SEM and XRD
results showed that calcite aggregates were formed on –OH surface, surface with
–NH 2 had no influence on crystal polymorph, only calcite was precipitated, a small
amount of vaterite was formed on –COOH surface due to the acidic electrostatic
adsorption (Fig. 6.27).
Calcium carbonate depositions on templates in vitro, of which carp lapillus
WSM and ASM absorbed on modified single crystal silicon substrate, were
characterized to have different crystal morphologies. WSM of lapillus (aragonite)
on –NH 2 and –COOH templates could induce aragonite crystals, while amorphous
calcium carbonate was also observed in the first 15 min. ASM of lapillus (aragonite)
on –NH 2 and –COOH templates could induce perfect needlelike aragonite particles,
which were similar to the aragonite sticks in natural lapillus, but ACC was not
found in the process. These results revealed that WSM and ASM have different
effects in the mineralization process: ASM could mediate perfect crystals compared
with WSM, but it did not have the size-mediation effect as WSM did. All the results
above explained that the formation of calcium carbonate crystals in lapillus is a very
complex process in which different kinds on protein matrices combined and
functioned. While, when ASM and WSM of carp asteriscus (vaterite) adsorbed
on the modified silicon substrate, the deposited crystal particles were similar to
those on template without any protein, they are calcite particles with only a few
vaterite ones (Fig. 6.28). Why WSM and ASM did not show the mediating effect,
the possible reason might lie in the absence of AIM during the extraction process,
on which WSM and ASM would absorb, so as to affect the mineralization process
of calcium carbonate.
6.5 Principles of Calcium Phosphate Mineralization
Mineralized calcium phosphate by collagen in vertebrates can be considered as a
material produced by self-assembly at ambient temperature (Cui et al. 2007). The
concept of self-assembling was defined by (Whitesides & Grzybowski 2002), i.e.,
self-assembling is the autonomous organization of components into patterns or
6 Principles of Calcium-Based Biomineralization
185
In in vitro mineralization experiments, glass substrate is often used because of its
good characters like extensive resources, convenient usage, cheap price, etc., but
glass surface may induce aragonite crystals. Single crystal silicon is another
commonly used substrate. The single crystal silicon substrate should be treated
by HF acid to remove surface oxide layer, then cleaned by acetone, absolute ethyl
alcohol, and deionized water to expose the (100) crystal plane. (Li 2008) tentatively
studied radical influence on polymorph of calcium carbonate crystals by surface
modification with –OH, –NH 2 and –COOH on single crystal silicon substrate.
WSM and ASM were absorbed on such substrate to prepare specific templates,
and then in vitro mineralization experiments were carried out. SEM and XRD
results showed that calcite aggregates were formed on –OH surface, surface with
–NH 2 had no influence on crystal polymorph, only calcite was precipitated, a small
amount of vaterite was formed on –COOH surface due to the acidic electrostatic
adsorption (Fig. 6.27).
Calcium carbonate depositions on templates in vitro, of which carp lapillus
WSM and ASM absorbed on modified single crystal silicon substrate, were
characterized to have different crystal morphologies. WSM of lapillus (aragonite)
on –NH 2 and –COOH templates could induce aragonite crystals, while amorphous
calcium carbonate was also observed in the first 15 min. ASM of lapillus (aragonite)
on –NH 2 and –COOH templates could induce perfect needlelike aragonite particles,
which were similar to the aragonite sticks in natural lapillus, but ACC was not
found in the process. These results revealed that WSM and ASM have different
effects in the mineralization process: ASM could mediate perfect crystals compared
with WSM, but it did not have the size-mediation effect as WSM did. All the results
above explained that the formation of calcium carbonate crystals in lapillus is a very
complex process in which different kinds on protein matrices combined and
functioned. While, when ASM and WSM of carp asteriscus (vaterite) adsorbed
on the modified silicon substrate, the deposited crystal particles were similar to
those on template without any protein, they are calcite particles with only a few
vaterite ones (Fig. 6.28). Why WSM and ASM did not show the mediating effect,
the possible reason might lie in the absence of AIM during the extraction process,
on which WSM and ASM would absorb, so as to affect the mineralization process
of calcium carbonate.
6.5 Principles of Calcium Phosphate Mineralization
Mineralized calcium phosphate by collagen in vertebrates can be considered as a
material produced by self-assembly at ambient temperature (Cui et al. 2007). The
concept of self-assembling was defined by (Whitesides & Grzybowski 2002), i.e.,
self-assembling is the autonomous organization of components into patterns or
6 Principles of Calcium-Based Biomineralization
185