Biomedical Engineering Reference
In-Depth Information
After implantation, the preferential dissolution of β-TCP phase
would result in functionally gradient porosity for bone ingrowth
[1116]. Functionally graded fluoridated HA (FHA) with a gradient
of fluoride [1117] and carbonated HA with a gradient of carbonate
[1118] were synthesized as well. HA/zirconia graded biocomposites
were fabricated to enhance the mechanical properties of HA while
retaining its bone bonding property [963]. TiO
and HA were
found to be a good combination for FGM providing both a gradient
of bioactivity and a good mechanical strength [1119]. Besides,
graded HA/CaCO
2
biocomposite structures for bone ingrowth were
developed [1120]. Functionally graded composite skull implants
consisting of polylactides, carbonateapatite, and CaCO
3
are known as
well [386, 387]. Thus, the research in this field is quite promising but
currently the mechanical properties of the available biocomposites
do not match the similar properties of bones [179].
3
6.4.9
Biosensors
A biosensor is a device for detection of an analyte that combines a
biological component with a physicochemical detector component.
Very briefly, it consists of three parts: a sensitive biological element;
a transducer or a detector element that transforms the signal
resulting from the interaction of the analyte with the biological
element into another signal; and associated electronics that is
primarily responsible for the display of the results in a user-friendly
way [1121].
The surface of biologically relevant calcium orthophosphates
(CDHA, HA, α-TCP, β-TCP, DCPD, DCPA) has an excellent ability of
adsorption for functional biomolecules such as proteins, albumins,
DNA, as well as some other types of chemicals. Therefore, several
calcium orthophosphate-based biocomposites and hybrid
biomaterials were found to be applicable for biosensor manufacturing
[354, 642, 1041, 1083, 1122-1127]. For example, formation of poly-
L-lysine/HA/carbon nanotube hybrid nanodimensional particles
was described and a general design strategy for an immunosensing
platform was proposed based on adsorption of antibodies onto this
biocomposite [1083]. In another paper, a hybrid material formed
by assembling of nanodimensional particles of gold onto nano-
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