Biomedical Engineering Reference
In-Depth Information
Biomineralization is an extremely complex microassembly process in
cell modulation [5]. The formation of biominerals is processed by space-
time templating of genes, proteins, mesenchymal cells, and further inter-
acting among organic supramolecular and inorganic precursor. This
process is the precise control of crystal nucleation and growth on the
molecular level. The main feature of the process is that precipitation of
inorganic mineral phase is controlled by the interaction of organic func-
tional molecules and inorganic mineral ions at the interface.
The aesthetic morphologies in the natural world have been of great
fascination to scientists in various fi elds. The biominerals often display
unusual morphology that are distinct from the inorganic minerals, and
the special and unusual morphologies are often targeted and emphasized
by scientists who work on biomimetic synthesis. Bio-morphogenesis has
been developed in synthesis of inorganic materials with comparable com-
plex forms of biominerals such as diatoms, etc., by a chemistry of con-
structing inorganic architectures via a biomimetic approach.
Biomineralization is different from general mineralization. In general
mineralization, if the solution containing calcium ions and phosphate ion
are mixed, the calcium phosphate will precipitate and further convert to
thermodynamically stable hydroxyapatite. In mineralization of bone or
teeth, calcium or phosphate ions are accumulated near special sites of the
matrix proteins in the intracellular or extracellular matrix, in which the
calcium phosphate nucleate, then grow together and fi nally constitute the
hard tissue. The reaction site of the matrix protein needs to be pre-self-
assembled in order to have mesostructure or hierarchical structure. The
self-assembly exists widely in the natural biomineralization.
An example of a study on natural biosilica is shown in Figure 13.2 [4].
13.2.2
Self-Assembly and Biomimic Synthesis
It can be extracted from the study of biomineralization that the most
important concepts are molecular recognition and self-assembly. Now
self-assembly has become the most important idea and basic principle of
basic and even supramolecular chemistry, and can supply the basis of bio-
mimetic synthesis at the microscopic scale.
Whitesides was the fi rst to interpret the concept of self-assembly [12].
He considered that ordered substance itself was formed by the synergistic
interaction among its building blocks, and the function of the assemblies
as well as the assembly “information” are stored in the assembled frag-
ments. Self-assembly is a fabrication process of molecule assemblies as well
as mesostructure. Firstly, it needs construction of the building block, i.e.,
primitives that are usually molecular assemblies formed by atoms, mol-
ecules, supramolecules, as well as uniformed nanoparticles with the deter-
mined component. Then the building blocks are assembled to mesoscopic
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