Page 33 - Plastics News October 2016
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FEATURES
that are a good fit for the shape and properties of the had been immobilized, in the process of removing lipocalin
molecules of just this compound. The probability that any molecules, the MOF skeleton - by this time redundant -
other protein will get caught in them is very, very small," was also destroyed. This treatment also resulted in an
explains PhD student Zofia Iskierko, the lead author of the extension of the polymer surface, leading to an increase
publication in the journalACSApplied Materials & Interfaces. in cavities available for the protein molecules and ensuring
The new polymer was prepared by molecular imprinting. better sensitivity of the chemosensor.
Molecules of lipocalin
were first surrounded by The polymer mass increases
appropriately selected after entrapping the lipocalin
(so called functional) molecules. Therefore, if it
monomers binding with were to be placed on a small
the protein at specific piezoelectric oscillator, its
locations characteristic easy-to-measure oscillation
only for itself. Then, a frequency would have to
cross-linking monomer was decrease. Another method of
introduced which combined identifying the presence of
with the functional one. lipocalin particles within the
Those monomers were later molecular cavities is to measure
subjected to polymerization, changes in the potential of
after which the lipocalin the recognition film, which
was washed out of the alters the current flowing in
resulting structure. Finally, the processing field effect
a stable polymer film was transistor component. Due to
obtained with molecular its simplicity and reliability,
cavities matching lipocalin this latter solution would
molecules both in terms of their local chemical features be particularly suitable for commercial chemosensors
as well as their size and shape. designed for mass production.
"When lipocalin molecules in the test solution come into "Our research is of a basic, laboratory nature. It is,
contact with a polymer formed in this manner, some of however, still a long way from the preparation of a polymer
them have the chance to be deposited in the cavities. capturing lipocalin to the mass production of low-cost
Proteins, however, are quite large and they are reluctant detectors for the prevention and early treatment of
to migrate through the polymer network. Therefore, the disease," says Prof. Kutner.
structure of our polymer had to be artificially loosened
enough to ensure the lipocalin molecules had the best Niels Bohr, the great Danish quantum physicist, used to say
access to the greatest number of cavities, but not that predicting was difficult, especially when it comes to
excessively, so that the polymer film would not collapse," the future. However, it seems reasonable to suppose that
describes Dr. Noworyta. in the next decade devices detecting various biomarkers
and warning early on of a threat to health will become
The IPC PAS researchers obtained the required porosity, an integral part of the ubiquitous smartphone. Diagnosis
whilst retaining sufficient mechanical strength, by would then become as simple as testing blood sugar
using MOF (metal-organic framework) inorganic-organic using today's glucose meters: it would suffice to connect
microporous materials. In terms of structure, MOF a removable, simple chemosensor with an appropriately
materials resemble three-dimensional lattices whose mesh selected polymer recognition film to the smartphone,
sizes depend on the type of metal atoms and connecting apply a little physiological fluid to it and... wait for the
ligands used. It was on this construction frame that the smartphone to display the result. Everyone would be able
actual recognition film was fabricated. When the polymer to carry out advanced medical diagnostics as often as they
deemed appropriate.
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