Polymer–Colloid Complexes Based on Cationic Imidazolium
Amphiphile, Polyacrylic Acid and DNA Decamer
Darya A. Kuznetsova 1 , Dinar R. Gabdrakhmanov 1, Denis M. Kuznetsov 1, Svetlana S. Lukashenko 1,
Valery M. Zakharov 2, Anastasiia S. Sapunova 1, Syumbelya K. Amerhanova 1, Anna P. Lyubina 1,
Alexandra D. Voloshina 1 , Diana V. Salakhieva 3 and Lucia Ya. Zakharova 1,*
Citation: Kuznetsova, D.A.;
Gabdrakhmanov, D.R.; Kuznetsov,
D.M.; Lukashenko, S.S.; Zakharov,
V.M.; Sapunova, A.S.; Amerhanova,
S.K.; Lyubina, A.P.; Voloshina, A.D.;
Salakhieva, D.V.; et al.
Polymer–Colloid Complexes Based
on Cationic Imidazolium Amphiphile,
Polyacrylic Acid and DNA Decamer.
Molecules 2021, 26, 2363. https://
doi.org/10.3390/molecules26082363
Academic Editors: Ramón G. Rubio
and Tamar Greaves
Received: 2 February 2021
Accepted: 15 April 2021
Published: 19 April 2021
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1 FRC Kazan Scientific Center, Russian Academy of Sciences, Arbuzov Institute of Organic and Physical
Chemistry, Arbuzov str. 8, 420088 Kazan, Russia; dashyna111@mail.ru (D.A.K.);
Nemezc1988@yandex.ru (D.R.G.); kuznetsov_denis91@mail.ru (D.M.K.); notassl@yandex.ru (S.S.L.);
anastasiya.strobykina@iopc.ru (A.S.S.); syumbelya07@mail.ru (S.K.A.); aplyubina@gmail.com (A.P.L.);
sobaka-1968@mail.ru (A.D.V.)
2 Kazan National Research Technological University, Karl Marx str., 68, 420015 Kazan, Russia;
zakharov_vm@mail.ru
3 Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University,
Kremlyovskaya St. 18, 420008 Kazan, Russia; DiVitSai@gmail.com
* Correspondence: luciaz@mail.ru; Tel.: +7-(843)-273-22-93
Abstract: The solution behavior and physicochemical characteristics of polymer–colloid complexes
based on cationic imidazolium amphiphile with a dodecyl tail (IA-12) and polyacrylic acid (PAA) or
DNA decamer (oligonucleotide) were evaluated using tensiometry, conductometry, dynamic and
electrophoretic light scattering and fluorescent spectroscopy and microscopy. It has been established
that PAA addition to the surfactant system resulted in a ca. 200-fold decrease in the aggregation
threshold of IA-12, with the hydrodynamic diameter of complexes ranging within 100–150 nm.
Electrostatic forces are assumed to be the main driving force in the formation of IA-12/PAA complexes.
Factors influencing the efficacy of the complexation of IA-12 with oligonucleotide were determined.
The nonconventional mode of binding with the involvement of hydrophobic interactions and the
intercalation mechanism is probably responsible for the IA-12/oligonucleotide complexation, and
a minor contribution of electrostatic forces occurred. The latter was supported by zeta potential
measurements and the gel electrophoresis technique, which demonstrated the low degree of charge
neutralization of the complexes. Importantly, cellular uptake of the IA-12/oligonucleotide complex
was confirmed by fluorescence microscopy and flow cytometry data on the example of M-HeLa cells.
While single IA-12 samples exhibit roughly similar cytotoxicity, IA-12–oligonucleotide complexes
show a selective effect toward M-HeLa cells (IC50 1.1 M) compared to Chang liver cells (IC50
23.1 M).
Keywords: imidazolium; amphiphile; polyacrylic acid; oligonucleotide; complexation