Photosensitizers (porphyrins) attack cancer cells and during photoactivation contribute to the generation of reactive oxygen species that damage various structures of cancer cells, which leads to their destruction. Porphyrins reach tumors through the blood and modelling of conditions for the transfer of porphyrins to the tumor (binding to blood proteins, the influence of pH and salt composition of the medium) is one of the most important problem of photodynamic therapy (PDT) of tumor. Ceruloplasmin (CP) is an important copper-containing plasma protein that actively binds photosensitizers (PS) and can play a certain role in the transfer of photosensitizers to the tumor. Changes in pH, as well as of salt composition in the tumor tissue and its cells can cause modifications in the complexes [CP + PS] and a possible separation of the PS from the complex can change the photodynamic process of tumor destruction. In this paper, it was shown that: 1) with a change in the pH of the medium from neutral to acidic, as well as with a change in the salt composition of the medium, significant conformational changes of ceruloplasmin and the transition of photosensitizers to the surface (for cationic porphyrins) or to the inside of the protein macromolecule (for chlorin e6) occur, with a partial separation of photosensitizers from protein; 2) CP can form complexes with photosensitizers and be an active carrier of PSs in the blood.
The relevance and importance of the development of new areas of tumor therapy is defined in connection with a strong increase in the level of oncological diseases. The latest global cancer data indicates a high mortality rate: the incidence of cancer increases to 18.1 million new cases and 9.6 million cancer deaths in 2018. Advances in nanostructures and nanotechnologies at the molecular scale in future can revolutionize several aspects of the diagnosis and treatment of body tumors. Search of highly specific and highly effective new therapeutic compounds is one of the most important directions in treatment of oncological diseases by noninvasive way. Currently, in clinics method of photodynamic therapy (PDT) of tumors based on photosensitizers (PSs) and light irradiation is widely used. At its application, the cancer cells are unable to develop resistance to such method of destruction.
In photodynamic therapy (PDT) of tumors, targeted therapy is one of the most successful directions. The goal of the present work was to study the formation of new potential photosensitizers, based on transferrin (Tf) and cationic porphyrins, for targeted binding with transferrin receptors of cancer cells. We studied non-covalent binding of three cationic porphyrins 1) meso-tetra [4-N-(2'-oxyethtyl) pyridyl] porphyrin (TOEt4PyP) 2) Zn-TOEt4PyP and 3) Zn-mesotetra [4-N-butyl pyridyl] porphyrin (Zn-TBut4PyP) with human transferrin by absorption and fluorescent spectroscopy as well as by gel filtration methods. It was shown that the investigated porphyrins and metalloporphyrins bind stably enough to the protein molecule. It was found that the porphyrins having Zn ion in porphyrin core as well as the peripheral OH - groups are linked better to the transferrin molecules. It can be apparently explained by Zn coordination with transferrin amino acids and the formation of the hydrogen bonds between OH - groups of the porphyrin and transferrin amino acids. It was shown that, for the transferrin-porphyrin complexes, singlet oxygen luminescence is significantly decreased due to the presence of transferrin amino acids which are efficient quenchers of singlet oxygen.
The binding of nanoparticles zeolite with a number of cationic porphyrins are studied. Previously, it was established that the main mechanism of binding the zeolite nanoparticles with cationic porphyrins is an ionic bond. Since binding of porphyrins as ligands to nanoparticles at the initial stage of interaction is determined by the Brownian motion of porphyrins, it is obvious that the interaction of porphyrins with nanoparticles may depend on the temperature. In the present paper by methods of absorption and fluorescence spectroscopy was studied the complexation of porphyrins with zeolite nanoparticles at different temperature conditions. It was established that there is a clear temperature dependence of the complexation of cationic metalloporphyrins with zeolite naonoparticles, and for correct determination of the percentage of binding must be strict thermostating of the experimental conditions.
Photodynamic inactivation of some microorganisms (St. aureus, E.coli) was investigated and their dependence on photo-physical properties of photosensitizers (PS) (cationic porphyrins and metalloporphyrins) was shown. One of the most important criteria for the effectiveness of the PS`s is the quantum yield of singlet oxygen (γΔ). Our investigations were shown that γΔ of metalloporphyrins, containing Zn, significantly higher than of metal-free porphyrins (85-97% and 77-79%, respectively). Previousl y experimentally we were found that under the action cationic porphyrins and metalloporphyrins on Gram (+) and Gram (-) microorganisms efficiency of metalloporphyrins Zn-TOEt4PyP and Zn-TBut4PyP in 3-5 times was higher than the metal-free porphyrins. In this study under the action of porphyrins and their Zn-derivatives on microorganism St. aureus such an effect was confirmed. Using the LED with a peak emission of 405 nm and a power density of 70 mW/cm2, and irradiation time of microorganisms from 5 to 30 minutes we have found, that at a concentration of 0.1 ug/ml the highest efficiency is observed of metalloporphyrin Zn-TBut3PyP. Upon irradiation of 10 and 15 min his efficiency is 3-5 times higher than the metal-free porphyrin TOEt4PyP, and irradiation for 30 min via Zn-TBut3PyP is practically completely kills microorganisms. These data correlate with the quantum yield of singlet oxygen for photosensitizers. The 30 mindirect sun exposure (power density of 70 mW/cm2) of photosensitizer solutions showed that a significant photobleaching of porphyrins and metalloporphyrins does not occur. Thus, Zn-containing cationic metalloporphyrins are highly efficient photosensitizers for photodynamic inactivation of microorganisms and PDT.
It is known that nanoparticles of colloidal silver and zeolites due to the porosity have an extremely large specific surface, which is an order of magnitude increases their sorption capacity. Previously we synthesized a set of water-soluble cationic porphyrins and metalloporphyrins and in the laboratory in vitro had shown their high effectiveness against the various cancer cell lines, and against a variety of microorganisms. The aim of this work was to study of processes sorption/desorption of porphyrins on nanoparticles of silver and zeolites. The interaction of cationic porphyrins with silver nanoparticles of 20 nm diameter was studied in the visible spectrum, in the range 350-800 nm. Investigation of sorption dynamics of porphyrins in the silver nanoparticles using two porphyrins: a) meso-tetra (4-N-butyl pyridyl) porphyrin (TBut4PyP), b) Ag-TBut4PyP, as well as of photosensitizer Al-phthalocyanine was carried out. Analysis of the dynamics of change in the absorption spectra for porphyrins TBut4PyP, Ag-TBut4PyP, Zn-TBut4PyP and Zn-TOEt4PyP by adding of nanoparticles of colloidal silver and zeolites leads to the conclusions: 1. nanoparticles of colloidal silver and zeolites are promising adsorbents for cationic porphyrins (sorption of 55-60% and 90-95%, respectively); 2. sorbents stable long (at least 24 hours) keeps the cationic porphyrins; 3. on nanoparticles of colloidal silver and zeolites an anionic and neutral porphyrins not be adsorbed or adsorbed bad.
Photodynamic inactivation (PDI) of microorganisms is successfully applied against Gram (+)
microorganisms. However the majority of photosensitizers poorly affect on Gram (-) microorganisms. At
present number of works have shown that cationic photosensitizers are able to induce photoinactivation both
Gram (+) and Gram (-) microorganisms. The purpose of this work was definition of more effective new
cationic pyridylporphyrins with various coordinated metals and functional groups for destruction of Gram (-)
microorganisms. The efficiency of new cationic porphyrins and metalloporphyrins (9 compounds) was tested
against Gram (-) microorganism E. coli (strain Κ-12). The testing results show high efficiency of
metalloporphyrins, especially silver complexes, against E. coli microorganism under dark conditions. 50 %
and 100 % cell growth inhibitory concentrations (IC50 and IC100 values, accordingly) of studied metallocomplexes
are considerably lower in comparison with metal-free porphyrins. At the same time the Zncomplexes
of porphyrins are more phototoxic than their metal-free analogues. Zn-metalloporphyrins with
allyl and butyl functional groups were shown the highest efficiency against E. coli. The photodynamic action
of cationic Zn -TBut4PyP metalloporphyrin against Gram(+) (St. aureus and St. epidermis) and Gram(-)
(E.coli, strain K-12 and Salmonella sp.) microorganisms was investigated. It is revealed, that Gram (+)
microorganisms were 3-5 times more susceptible to the compounds' phototoxic influence than Gram (-)