The formation of calcium
phosphate phases is extremely important in a biomedical engineering context.
These phosphates are used in many applications, such as grafts, drug-delivery
processes and evaluation of the bioactivity of metallic surfaces. Considering
this scenario, it is useful to evaluate the thermodynamic conditions for the
precipitation of phosphates of biomedical interest, mainly hydroxyapatite. In
this work, we investigate the effects of two important factors using a
thermodynamic framework: 1) carbon dioxide partial pressure; and 2)
buffer type (2-Amino-2-hydroxy- methyl-propane-1,3-diol, known as TRIS and
2-[4-(2-hydroxyethyl)piperazin-1-yl] ethanesulfonic acid, also called HEPES),
on the driving force behindthe precipitation of calcium phosphates in
simulated body fluids. The in silico results show that the pH value is governed by carbon dioxide content, as
expected to occur in vivo.Moreover,
the buffers can deplete the free calcium available in solution and,
consequently,can cause difficulties in the calcium phosphate precipitation.
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