Complexes on the base of marigold's pigments and ytterbium will be used in cancer therapy
Scientists elaborated new organometallic complex on the base on marigold's pigments and ytterbium that had fluorescence and was able to produce reactive oxygen species. Such compound thanks to the ability to luminescence potentially can be used in photoelectronics, and due to toxic properties of reactive oxygen species - in biomedicine for cancer treatment. Results of the research are published in Journal of Molecular Structure.
When scientists elaborate modern electronic and optical devices, in particular, solar batteries and photodetectors, they increasingly tend to use complexes that consist of rare metals and organic residues – ligands. Regulating conditions of their synthesis, researchers control finite structure of complexes, that define their ability to luminesce. Besides this during stimulation with visible light such materials produce reactive oxygen species - compounds that are toxic in large quantities and destroy membranes, proteins and DNA of cells. This property increases opportunities of applying organometallic complexes in biomedicine, in particular, in cancer treatment. However still there aren't enough examples of synthesis of organometallic complexes, that effectively generate reactive oxygen species.
Scientists from Immanuel Kant Baltic Federal University (Kaliningrad) together with colleagues elaborated complex, that consists of ions of rare metal ytterbium and extracts, separated from marigold's flowers (Tagetes patula L.). To achieve this aim authors dried and grinded flowers and then dissolved this dry matter in ethanol. Obtained extracts researchers mixed with alcohol solution of ytterbium's ions. At the same time scientists created solutions with different concentrations of ytterbium's ions – from 0,865 to 17,3 gram per liter.
Authors tested the ability of pure extracts and obtained mixtures with ytterbium to absorb and emit light. It turned out that plants' extracts mainly absorbed ultraviolet lights, however after scientists added to them ions of ytterbium absorption peak moved to the field of violet light. Such change points at the formation of organometallic complex, because ions of ytterbium by themselves absorb more long wave infrared light.
Then authors irradiated compounds with blue light and registered their luminescence. Pure plant extracts emitted red light. Authors also found out that addition of ytterbium increased the intensity of their luminescence, approximately in 6,3 times. Researchers suggested that ions of ytterbium, that absorbed light energy, passed it to organic components of complex, thus increasing amount of energy, that was emitted by complexes in the form of luminescence.
Besides this, organometallic complexes, in contrast to extracts, emitted orange-yellow light. The appearance of this diapason is connected with the change of the electronic structure of organic molecules under the influence of ytterbium. The luminescence of organometallic complexes also continued about thrice longer than luminescence of pure plant extracts.
Scientists noticed that addition of ytterbium also led to generation of reactive oxygen species by the complex. Authors found their formation by the appearance of infrared radiation. With the help of integrating sphere – device that helps to measure power of luminescence – authors estimated efficiency of generation of reactive oxygen species by the elaborated complex. It was comparable with previously published information on organometallic complexes which also included ytterbium. However, in contrast to its predecessors this new complex with ytterbium was faster and easier to synthesize. Thus, scientists elaborated new effective generator of reactive oxygen species, that potentially could be applied for cancer treatment.
"Our research opens new approach to elaboration of luminescent compounds on the base of metals. We suggest, that complex on the base of ytterbium will be able to bind molecular oxygen well. That enables to treat the created compound as potential oxygen sensor in various systems, including biological ones. We are planning to dedicate our further research exactly to this theme", – tells Anna Tsibulnikova, senior research associate of REC "Fundamental and applied photonics. Nanophotonics" of Immanuel Kant Baltic Federal University.
In research took part members of Kaliningrad State Technical University (Kaliningrad), Yanka Kupala State University of Grodno (Belarus) and Herminio Ometto de Ararras University Center (Brazil).
More information:
doi.org/10.1016/j.molstruc.2025.143216
Provided by Immanuel Kant Baltic Federal University
