Biomedical Engineering Reference
In-Depth Information
Si
Si
Remove template
Rebind
NH
NH
H
TEOS
Ext-Si
OC
O
CH
3
O
1
2
3
Figure 11.32
Scheme for the synthesis of (A) CNTs@Est-MIPs. h e surface of purii ed
CNTs was converted to a silica shell by a sol-gel process using TEOS and APTES in the
presence of CTAB to give core@shell CNTs@SiO
2
(1). h e CNTs@SiO
2
reacted with Est-
Si to produce a silica surface functionalized with estrone-imprinted polymer (2). At er
removing estrone by a simple thermal reaction, estrone-imprinted polymer coated CNTs
were obtained (3) [71].
11.2.2 h
in Film Imprinting
A thin i lm is a layer of material ranging from fractions of a nanometer
(monolayer) to several micrometers in thickness. A familiar application of
thin i lms is the household mirror, which typically has a thin metal coating
on the back of a sheet of glass to form a rel ective interface. h e process of
silvering was once commonly used to produce mirrors. Several imprinted
thin i lm of nanometer thickness were also reported in the literature.
Recently, screen-printed electrodes were modii ed with MWCNTs and
molecularly imprinted membranes (MIM) were directly synthesized on
these modii ed electrodes using the in situ thermal polymerization tech-
niques [72]. h e sensing system was easily established by connecting the
screen-printed electrode modii ed with MWCNT-MIM to an electro-
chemical analyzer through an electrode slot. h e signal for the determi-
nation of ractopamine was recorded using dif erential pulse voltammetry
(DPV) and the optimization for the experimental conditions was also con-
ducted. h e results showed that the response of the sensor to concentration
of ractopamine displayed a linear correlation over a range from 20 nM to
200 nM with a detection limit of 6 nM, demonstrating favourable sensitiv-
ity and selectivity for the detection of ractopamine. h e recoveries reached
87.7-96.9% based on pig urine samples.
TiO
2
nano-thin i lms with imprinted (R)- and (S)-enantiomers of pro-
pranolol, 1,1'-bi-naphthol, and 2-(4-isobutylphenyl)-propionic acid were
fabricated by Mizutani
et al.
on quartz plates by spin-coating their solu-
tions with Ti(O-nBu)
4
in a toluene-ethanol mixture (1:1, v/v) [73]. At er
template removal, the imprinted i lms showed better binding for original
