Biomedical Engineering Reference
In-Depth Information
spherical molecularly imprinted polymers were compared with the spheri-
cal nonimprinted polymers, both in organic (acetonitrile) and water media.
Finally,
in vitro
release studies were performed in plasma simulating l uids.
h e interactions between the template and the functional monomer are
key to the formation of cavities in the imprinted nanogels with high molec-
ular recognition properties [92]. Nanogels with enzyme-like activity for
the Kemp elimination have been synthesized using 4-vinylpyridine as the
functional monomer and indole as the template. h e weak hydrogen bond
interaction in the complex is shown to be able to induce very distinctive
features in the cavities of the imprinted nanogels. Although the percent-
age of initiator used in the polymerization, ranging from 1% to 3%, does
not have a substantial ef ect on the catalytic rate, it considerably reduces
the imprinting ei ciency. h e alteration of the template/monomer ratio
has also been investigated, and the data show that there is considerable
loss of imprinting ei ciency. In terms of substrate selectivity, a number of
experiments have been performed using 5-Cl-benzisoxazole as substrate
analogue, as well as 5-nitro-indole as template analogue, for the prepara-
tion of a dif erent set of nanogels. All the kinetic data demonstrate that
the chemical structure of the template is key to the molecular recognition
properties of the imprinted nanogels that are closely tailored and able to
dif erentiate among small structural changes.
12.3.5 Nanoimprint Lithography
Nanoimprint lithography (NIL) can generate well-dei ned nanostructures
with high ei ciency and at very low cost. Molecular imprinting is a “bot-
tom-up” technique creating a polymer layer exhibiting structures with a
molecular selectivity [93]. Such polymer structures may be employed as
molecular recognition sites for sensing applications. Herein, the authors
combine NIL with MIP and they are able to obtain micro- and nanopat-
terns of polymer with features down to 100 nm that show high molecular
selectivity.
12.4
Conclusions and Future Outlook
h e current status, challenges, and highlighted applications of MIPs have
been described in this chapter. Major work has been performed to resolve
the problems associated with the development of MIPs during the last few
years. Owing to their high selectivity, high sensitivity, low cost, and ease
of preparation, MIPs have been extensively utilized as chromatographic
