Biomedical Engineering Reference
In-Depth Information
polymerisation technique. h e prepared ion-imprinted nanostructured
polymer particles have an increased selectivity toward Pb(II) ions over
a range of competing metal ions with the same charge and similar ionic
radius. h is ion-imprinted polymer is an ei cient solid phase for extrac-
tion and preconcentration of lead ions in complex matrixes [78].
Forouzani
et al.
have been reported nalidixic acid imprinted uniformly
sized polymers in the nanometer range by precipitation polymerization
using methacrylic acid (MAA) and methyl methacrylate (MMA) as func-
tional monomers at dif erent mole ratios [79]. h e ef ect of combination
of MAA-to-MMA on the morphology, binding, recognition and release
behaviors of the i nal particles were studied. h e produced polymers were
characterized by dif erential scanning calorimetry and their morphology
was precisely examined by scanning electron microscopy. A very uni-
form imprinted nanospheres with diameter of 120-180 nm are obtained.
Among the MIP nanospheres the MIPs using combination of MAA and
MMA showed nanospheres with lowest mean diameter (120 nm) and the
highest selectivity factor (9.7). Moreover, release experiments showed the
controlled release of Nalidixic acid in longtime period.
In another work, Cu
2+
-mediated salbutamol-imprinted polymer
nanoparticles, synthesis via precipitation polymerization, were reported by
Alizadeh
et al.
, which later on mixed with graphite powder and n-eicosane
in order to fabricate a modii ed carbon paste electrode [80]. h is electrode
was then applied for indirect dif erential pulse voltammetry determination
of salbutamol. In the presence of Cu
2+
ions, the formed Cu
2+
-salbutamol
complex was adsorbed in to the pre-designed cavities of the MIP particles,
situated on the electrode surface. Since the electrochemical signal of sal-
butamol was intrinsically small, the oxidation peak of the participant Cu
2+
,
at er reduction step, was recorded and used as an indication of salbutamol
amount, adsorbed in the electrode. Dif erent variables inl uencing the sen-
sor performance were studied and the best conditions were chosen for the
determination purpose.
Folic acid has been used as a template to generate molecularly imprinted
polymers (MIPs), both thin i lms and nanoparticles [81]. Systematic studies
on binding behavior include using two dif erent polymer systems, namely
methacrylates and acrylate-vinyl pyrrolidone copolymers. Both yield sen-
sor characteristics with lower limits of detection of 1-30 ppm with QCM
(quartz crystal microbalance), whereas the nonimprinted polymers do not
generate any signals. For methacrylate-based systems, switching from thin
i lms to MIP nanoparticles increases sensitivity by a factor of 3.0 and selec-
tivity toward metabolites (leucovorin and anhydroleucovorin) from broad-
band to specii c. In contrast to this, in poly vinyl pyrrolidone based materials
