Biomedical Engineering Reference
In-Depth Information
In future, an ability to functionalize surfaces with different
molecules of varying nature and dimensions by means of their
attachment to cells will enable them to act selectively on biological
species such as proteins and peptides. The capability of synthesizing
and processing of nanodimensional and nanocrystalline calcium
orthophosphates with the controlled structures and topographies, in
attempts to simulate the basic units of bones and teeth, will provide
a possibility of designing novel proactive bioceramics necessary
for enhanced repair efficacy. The various primary positive results
on the biocompatibility and biomimicity of novel nanostructured
bioceramics merit further confirmations. Namely, much work
remains to be undertaken to address the following key challenges
and critical issues of nanodimensional and nanocrystalline calcium
orthophosphates [663]:
•
Consistency of the processing technologies;
•
Optimization the structure and properties mimicking bones;
•
Matching the strength of nanodimensional and nanocrystalline
constructs with those of bones in order to provide a uniform
distribution of stresses (load sharing);
•
Optimizing bioresorption without comprising the mechanical
properties;
•
Assessing the inflammatory response to validate their
biosafety.
Furthermore, substantial research efforts are required in the
analysis of cells and their different behaviors with regard to their
interactions with nanodimensional and nanocrystalline calcium
orthophosphates [663]. An important but still unsolved question is
how the cells can recognize the particle dimensions and crystallinity
of nano-sized calcium orthophosphates. What is the signal for
nanodimensional biomaterials to promote cell proliferation and
differentiation and how can the pathways be found out? According
to the experiments results on transfection, nano-sized particles
can enter into cells readily but many details of this process remain
unclear. Namely, the pathways for the nano-sized particles to
enter the cells through the membranes should be revealed [664].
A greater influence of the hydrated surface layer with labile ionic
species of smaller particles and crystals (see section 3.5) might be
another possible option, to be confirmed experimentally. Then, it is
important to examine the metabolism process of nano-sized calcium
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