Biomedical Engineering Reference
In-Depth Information
O
O
OH
(A)
C
OH
OH
C
OH
O
O
O
n
O
C
OH
C
O
OH
HC1 2 h 25°C
O
n
DMAP/DCC
O
O
C
HNO
3
4 h 140°C
C
OH
OH
12 h 25°C
OH
O
C
OH
O C
O
O
OH
(1)
O
OH
-
(B)
PO
4
3-
(C)
Ca
2+
Ca
2+
PEG
O
Hydroxyapatite
FIGURE 18.8
(A) Scheme of synthetic route for the preparation of PEG-MWCNT, (B) scheme of biomineralization mechanism
of the preparation of HA-PEG-MWCNT, and (C) SEM and inserted TEM images of HA-PEG-MWCNT.
Reproduced with permission from Ref.
[95]
.
20 nm. In vitro biomineralization process was performed on the surface-treated 3-D CNFs. The
results showed that surface treatment of CNFs in nitric acid promoted the mineralization on CNFs.
18.6.2
Sol
gel/electrospinning
Another method to fabricate CaP/CNF hybrid is the preparation of CaP nanoparticles embedded
CNFs, produced in our lab, by combining sol
gel and electrospinning techniques
[98,99]
.Among
the different techniques available for the production of CaP compounds, including co-precipitation,
solid-state reactions, hydrothermal reactions, and electrochemical deposition, the sol
gel technique is
the simplest and most versatile to produce ceramic materials with high homogeneity
[85,100]
.The
sol-gel technique is generally based on hydrolysis reaction followed by the condensation of
the precursors to achieve the formation of colloidal particles (sol) and subsequent formation of
a three-dimensional network (gel). Calcination, sintering, or chemical conversion of the precursor
into the desired ceramic at an elevated temperature is conducted with concomitant removal of all
organic components from the precursor fibers. To produce CaP compounds, like HA and
-TCP, cal-
cium nitrate and triethyl phosphate (TEP) are usually used as the precursors. A feasible way to pro-
duce ceramic nanofibers is to electrospin the above sol
β
gel solution and subsequently calcinize
