Fitted with molecular pincers, the polymer synthesized in collaboration between the Institute of Physical Chemistry of the Polish Academy of Sciences and the Department of Chemistry, Wichita State University, made it possible to fabricate a chemical sensor for determination of nicotine in solution. Dr. Eng. Krzysztof Noworyta from the IPC PAS works with the prototype nicotine trap in Warsaw’s Fajka Bar. Image: IPC PAS/Grzegorz Krzyzewski
newly synthesized polymer, fitted with molecular pincers of carefully
tailored structure, effectively captures nicotine molecules and its
analogues. The polymer can be used for fabrication of sensitive and
selective chemical sensors to determine nicotine in solutions, and in
the near future also in gases. Moreover, the polymer is suitable for
slow, controlled release of nicotine, e.g., for therapeutic purposes.
collaboration of researchers of the Institute of Physical Chemistry of
the Polish Academy of Sciences (IPC PAS) and of the Department of
Chemistry, Wichita State University, Wichita, KS, has resulted in
fabrication of a polymer trap for nicotine. Bearing molecular pincers,
the polymer effectively captures nicotine molecules and its analogues,
and can also release them in a controlled way. The compound will be used
in reusable chemical sensors for determination of nicotine for
industrial and biomedical purposes as well as in patches for smokers to
evenly release nicotine to the body for a prolonged time.
first nicotine trap has been synthesized by our U.S. partner, Prof.
Francis D’Souza, several years ago. It was a sort of molecular pincers,
molecules that freely move in solution and form complexes with nicotine
therein. Recently, our US-Polish team has been able to fix the pincers
inside a polymer. The substance is solid, and that’s why we could use it
to construct chemosensors”, says Prof. W?odzimierz Kutner from IPC PAS.
core of the polymer nicotine trap, which has been recently filed for a
patent, is a metalloporphyrin derivative, a substance present, i.a., in
human blood. The molecule contains a ring (a macrocycle) with a
centrally located zinc atom and amide pincers attached to this ring.
Nicotine binds to this polymer with its two nitrogen atoms: one binds to
the zinc atom, whereas the other to the pincers.
is due to the specific two-point binding that we are surer that the
captured molecule is nicotine”, stresses Dr. Krzysztof Noworyta from IPC
PAS, adding that in one of the devised polymers the pincers are located
on both sides of the zinc containing-ring plane.
“Such a design clearly increases the efficiency of nicotine trapping”, says Noworyta.
nicotine, the polymer captures also a cotinine alkaloid produced in the
metabolism of nicotine and other alkaloids often accompanying nicotine,
e.g., myosmine. Polymer binding to nicotine is durable but reversible.
It is the property why the new chemosensors for determination of
nicotine and its analogues can be used repeatedly.
Polymer nicotine trap is composed of a porphyrin derivative (black), in which amide pincers (green) are attached to the zinc (violet) containing macrocycle (blue). The nicotine molecule is shown in red. Lower graphics is a 3D-visualisation of the polymer. (Source: IPC PAS/Tentaris/ACh)
is detected by means of a piezoelectric resonator coated by
electropolymerization with a submicrometer thick polymer film. The
captured nicotine increases the mass of the film resulting in a decrease
in the resonant frequency of the resonator that is easy to measure. “It
can be said that we are weighing a film of our polymer all throughout
the experiment. Because we know the initial polymer mass and we know
that the polymer selectively captures nicotine and its analogues, an
increased mass of the film means that these compounds are present in
solution”, explains Noworyta.
acoustic bulk wave resonators used in experiments with the new polymer
allow determining nicotine in solutions. In the near future, the
researchers from IPC PAS plan to establish collaboration with
manufacturers of surface acoustic wave resonators. These resonators
oscillate at significantly higher frequencies, thus being more
sensitive, and after coating with the nicotine capturing polymer film
could detect nicotine also in gases.
the method described herein, the detection and determination of
nicotine do not need to be confined to weighing. Because nicotine is
electroactive, the researchers from IPC PAS are going to measure
oxidation current of nicotine trapped in the polymer in parallel with
the resonant frequency measurement. Simultaneous measurement with these
two methods will increase the detection reliability.
polymer with pincers for nicotine can be used, among others, in
chemosensors devised to analyze nicotine content in tobacco leaves and
in biomedical studies to determine nicotine metabolites in patients’
body fluids. Another potential application is nicotine patches to help
quit smoking. The new polymer could be used for prolong and smooth
release of nicotine.