Gold nanoparticles and propranolol drug: single electron transfer instead chiral discrimination
Ekaterina A. Kolobova 1, Kseniia N. Makarova 1, Elena V. Solovyeva 1;
1Saint-Petersburg State University, Saint Petersburg, Russia
Abstract
The propranolol drug from β-adrenergic blockers family is one of the molecules for which a chiral recognition has been reached by surface-enhanced Raman scattering (SERS) using metal nanoparticles modified with a chiral selector. Therefore, a deep insight into the interaction of propranolol with plasmonic surface (bare or modified) is of great interest. To reliable conclusions, various methods sensitive to enantiomers have to be involved. Capillary electrophoresis meets this requirement and can be used as an accompanying method.
A series of experiments, in which the sorption of propranolol on gold nanoparticles with bare and modified surface was performed. After different times of exposition, propranolol - gold nanoparticles dispersions were centrifuged, followed by electrophoretic analysis of the supernatant with enantiomeric separation. The SERS spectra were recorded for the solid phase.
After sorption of propranolol on gold nanoparticles, unknown peak was observed on the electropherogram of supernatant besides two peaks from the pair of enantiomers. HPLC-MS experiments showed that this is N-desisopropylpropranolol with m/z ratio of 218.2. Thus, plasmon-assisted conversion of propranolol to its dealkylated product occurs on the gold surface. This process presumably takes place through the single electron transfer mechanism. The SERS spectra turned out to be identical for propranolol and its metabolite that emphasizes an importance of using independent methods to study subtle phenomena.
This work was supported by Saint-Petersburg State University, project № 122040800256-8. The authors would like to thank the Research Park of SPbU.
Speaker
Makarova Kseniia Nikodimovna
Saint Petersburg State University
Russia
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Discussion
Lomova Maria
How stable are gold nanoparticles in aquatic and biological environments?
Makarova Kseniia Nikodimovna
The stability of nanoastics is characterized by the zeta potential of their surface; the colloidal system is stable when its value is more than 30 mV in absolute value. For the nanoparticles used, the zeta potential is about -40 mV, which indicates their stability.
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