Biomedical Engineering Reference
In-Depth Information
going from thin i lms to MIP nanoparticles does not increase sensitivity, but
selectivity: thin i lms yield selectivity factors of 2-3 between folic acid and
its metabolites, whereas nanoparticles do not show any response toward
the latter and thus can be regarded specii c. Hence, not only the heterocy-
clic backbone, but also the carboxylic groups of the folic acid molecule play
fundamental role in detection. Vinyl pyrrolidone thus is the more suitable
monomer than methacrylic acid to ensure these properties.
In another work, Tahir alizadeh
et al.
reported the synthesis of nanopar-
ticles of promethazine-imprinted polymers by the ultrasonic assisted sus-
pension polymerization in silicon oil [82]. h e MIP particles were then
embedded in a carbon paste (CP) electrode in order to prepare the MIP
(nano)-CP electrode. h is electrode showed higher response to analyte,
compared to the carbon paste electrode, modii ed with nonimprinted
polymer (NIP (nano)-CP), with response ranges of 4×10
-12
-1×10
-10
M and
1×10
-9
-1×10
-7
M with the sensitivities of 31.7 and 0.17 μA nM
-1
, respec-
tively. h e lower detection limit of the sensor was calculated equal to
2.8x10
-12
M (S/N). h e sensor was applied for promethazine (PMZ) deter-
mination in plasma samples without applying any sample pretreatment.
Similarly, the author has also reported a potentiometric sensor based on
nanosized molecularly imprinted polymer (MIP) for the determination of
promethazine [83]. h ese MIP nanoparticles were prepared by two meth-
ods: microemulsion polymerization and suspension polymerization, also
known as nano-MIP(1) and nano-MIP(2). h e nano-MIP(2)-based sensor
showed higher selectivity and sensitivity, compared to the nano-MIP(1)-
based electrode. Both electrodes demonstrated a response time of 5s, a
high performance and a satisfactory long-term stability. h e electrodes
were applied for PMZ determination in syrup and serum samples.
Asadi
et al.
used novel synthetic conditions of precipitation polymeriza-
tion to obtain nanosized cyproterone molecularly imprinted polymers for
application in the design of new drug delivery systems [84]. h e scanning
electron microscopy images and Brunauer-Emmett-Teller analysis showed
that MIP prepared by acetonitrile exhibited particles at the nanoscale with a
high degree of monodispersity, specii c surface area of 246 m
2
g
−1
, and pore
volume of 1.24 cm
3
g
−1
. Controlled release of cyproterone from nanopar-
ticles was investigated through
in vitro
dissolution tests and by measuring
the absorbance by HPLC-UV. h e pH dissolution media employed in con-
trolled release studies were 1.0 at 37 C for 5 h and then at pH 6.8 using the
pH change method. Results show that MIPs have a better ability to control
the cyproterone release in a physiological medium compared to the NIPs.
Imprinted nanoparticles were also employed as packing material in solid
phase extraction technique. A new, simple, rapid, and sensitive solid-phase
