Svenskaya Yu.I.1, Lomova M.V.1, Markin A.V.1, Lukyanets E.A.2, A.Bartkowiak3, Markvicheva E.A.4, Gorin D.A.1
1Saratov State University, Saratov, Russia
2State Research Centre of Organic Intermediates and Dyes“NIOPIC”, Moscow, Russia.
3West Pomeranian University, Szczecin, Poland
4Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.
Photodynamic therapy is rather new and promising method for cancer treatment [1,2]. It is based on the usage of light-sensitive substances, namely photosensitizers (photodynamic dyes), and irradiation with determined wavelength. Photosensitizes are accumulated mostly within tumor tissue which allows to destroy them by irradiation using wavelength corresponding to the absorption maximum of these photodynamic substances. Irradiation induces a photochemical reaction leading to the death of cancer cells.
Although photodynamic dyes have selective accumulation, there are some cytotoxicity effects because of the interaction of phodynamic dyes with blood proteins . To minimize these effects, we proposed phodynamic dye encapsulation using calcium carbonate cores and layer-by-layer electrostatic adsorption technique. We suggested that usage of calcium carbonate core and layer-by-layer electrostatic adsorption method for phodynamic dye encapsulation could be employed for targeted drug delivery to decrease toxicity of phodynamic dyes. We encapsulated photosensitizers within core-shell structures. “Dye-in-core” and “dye-in-shell” structures were prepared.
As a photodynamic dye Photosense was used . As templates for fabrication of core-shell structures calcium carbonate microparticles were used. Previously described technique for core fabrication was applied . However, we proposed some modifications of this method, namely co-precipitation of anionic polyelectrolyte at synthesis and ultrasound treatment.
An average size of the prepared microparticles was 1 μm. Polyelectrolyte shells were prepared by self-assembly method using biocompatible polymers (chitosan and dextran sulfate sodium salt) adsorbed layer-by-layer on the calcium carbonate microparticles. The photodynamic dye was embedded either into calcium carbonate cores by direct precipitation at synthesis (“dye-in-core” structures) or within the polyelectrolyte shells (“dye-in-shell” structures). Dye presence in core-shell structures was confirmed by confocal Raman microscopy. The photodynamic dye was localized into core-shell structures. To estimate phothodynamic dye concentration in structures, optical density spectra were measured. It was established that for “dye-in-core” structures more photosensitizer has been encapsulated.
As a result, biocompatible dye-filled structures of two types (“dye-in-core” and “dye-in-shell”) were prepared and optimized. Possibility of shell structure modification and simplicity of the preparation technique are significant advantages of LbL assembly method. Usage of biocompatible polymers allows to apply the obtained core-shell structures for biomedicine. These structures could be employed for targeted drug delivery systems.
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Dr. Yulia Igorevna Svenskaya
Sararov State University, Senior Research Scientist
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