The photodynamic inactivation of viruses by a microporous photocatalytic element made of copper or copper alloy is the very method of ensuring biosafety that the article is about. Based on this method, encouraging results of virological studies (using the influenza virus as a test) were obtained as well as the equipment solving the strategic task of antiviral (influenza, COVID-19, etc.) disinfecting and sterilizing of confined spaces air, including air of medical premises, was developed.

This paper presents a review of papers associated with the study of in vitro spectral, fluorescence, and photosensitizing properties, as well as the photostability of low-toxicity photosensitizers based on endogenous porphyrins—the disodium salt of 2,4-di(1-methoxyethyl) deuteroporphyrin IX (dimegin) and the tetrapotassium salt of coproporphyrin III—in comparison with chlorin preparations for medical purposes—Photoditazin, Radachlorin, and Fotolon—when photosensitizer solutions are irradiated in the visible range. The influence of transport additives and proteins on the properties mentioned above is discussed and studied. The results of the study are evidence that it is promising to use drugs based on endogenous porphyrins as effective agents for photodynamic therapy and fluorescence diagnosis, where, along with the photophysical properties of the photosensitizer, a key role is played by photostability, low toxicity, and accumulation selectivity in the pathological foci of the organism, and this is directly associated with the chemical structure of the drug. The results of the latest work carried out at S. I. Vavilov State Optical Institute on this specialization are treated separately.

The photosensitizing ability of an agent based on chlorin e6 (Photoditazin), which is used for photodynamic diagnosis and therapy, is compared with that of a new preparation on the basis of coproporphyrin III in the environment of a phosphate buffer and a simulated biological environment (albumin solution). The efficiency of singlet-oxygen production was estimated by EPR spectroscopy and spectroscopy in the UV and visible ranges with the use of “chemical traps” of singlet oxygen. By irradiating drugs with LED emission centered at λmax = 520 nm, we determined the quantum yield of singlet-oxygen production in a buffer solution; the obtained values are 0.60 and 0.37 for chlorine and coproporphyrin, respectively. The steady-state concentration of singlet oxygen upon irradiation of solutions of the studied photosensitizers with concentrations of 12–43 μМ and the density of radiation power within the 6–96 W/cm2 region was found to be in the region of 1010–1011 molecules/cm3. It is shown that the introduction into the solution of egg albumin (0.1%) reduces the sensitizing properties of the two drugs by two to three times, while the efficiencies of the preparations with respect to singlet-oxygen production become almost identical (0.19 and 0.17).

The photodynamic properties of a new photosensitizer—dimegin (disodium salt of 2,4-di(1- methoxyethyl)-deuteroporphyrin-IX)—are studied in comparison with the properties of photosensitizers used in medical practice, namely, Photoditazine (dimethylglucamine salt of chlorin e6) and Radachlorin (trisodium salt of chlorin e6). The spectral characteristics, singlet oxygen generation ability, luminescence efficiency, and photostability of these photosensitizers are studied upon irradiation by light-emitting diode arrays in different spectral ranges. The ability of photosensitizers to generate singlet oxygen was estimated with the use of tryptophan as a chemical trap. The photostability was estimated by a change in the optical density of solutions in the Soret band after irradiation. It is shown that the photodynamic properties are related to the specific features of the optical absorption spectrum of the material. The results of this work testify to the possibility of using the Dimegin photosensitizer as an efficient drug for photodynamic therapy and fluorescent diagnostics. Comparative studies of luminescence, singlet oxygen generation, and photostability have shown that Dimegin surpasses Photoditazine and Radachlorin in many characteristics. In the future, these studies will help to choose the most efficient irradiation sources for photodynamic therapy and fluorescent diagnostic.

Background: The problem of transfution-transmitted infections still remains serious and actual for health care despite the detailed testing of donors. Human immunodeficiency virus, hepatitis B and C viruses and human cytomegalovirus are among the most dangerous pathogens that can be transmitted with blood. Previously, a composition consisting of fullerene layer applied on silica gel particles was shown to inactivate influenza virus up to complete loss of infectivity.Methods: In the present study the unit has been developed with source of irradiation whose spectrum is appropriate for solid-phase fullerene. The ability of the unit to inactivate the enveloped influenza virus in protein fraction of donor blood has been studied.Results: It was shown that at optimized conditions complete inactivation of enveloped virus of extremely high initial titer (7.0-9.5 log(10)EID(50)/0.2 mL) in the solution of albumin was achieved after as short time as 30 min of irradiation. This process did not affect the oxidative metabolism of neutrophils and membranes of erythrocytes evaluated by NBT reduction test and morphological analysis of erythrocytes, respectively.Conclusion: The data obtained suggests that the method described can be recommended for further development and optimization of the procedure of inactivation of viruses in the preparations of the plasma of donor blood. (C) 2014 Elsevier B.V. All rights reserved.

We resume a complex study of a new Coproporphyrin III preparation obtained in vitro via microbiological synthesis in environment of a cultural medium of Arthrobacter globiformis with gaining of the coproporphyrin III tetrapotash salt sterilized aqueous solution with 94.5% purity. The main impurities have porphyrinic nature.The absorption spectrum shows that the preparation has multiple excitation bands in visible region with most pronounced maxima at 501 nm, 535 nm, and 556 nm, and a weak one at 606 nm. The most effective spectral range of its electronic states excitation can serve the region of a Soret band with maximum at 404 nm. Comparative luminescent and photosensitizing properties of Coproporphyrin III and Fotoditazin preparations have been studied. Luminescence and singlet oxygen quantum yields have been determined to be 0.03 and 0.37 (Coproporphyrin III) and 0.05 and 0.6 (Fotoditazin) correspondingly. A reduction of the quantum yields values at an introduction of a biological additive into aqueous solutions of the given preparations has been found.Preclinical trials of the preparation are performed. It is shown that Coproporphyrin III toxicity value is LD50 = 2400 +/- 120 mg/kg, that allows to rank this preparation to the (V) class of almost nontoxical medicinal agents. It is shown that the preparation Coproporphyrin III has no teratogenic and allergenic properties and does not damage erythrocytes and thrombocytes. Absence of an influence of the preparation on the blood flow speed has been established. The results obtained thereby testify the absence of contra-indications for clinical tests of the Coproporphyrin III preparation on indicators of sharp toxicity.

A new type of solid-phase photosensitizer has been proposed and created on the basis of aggregated fullerene C60 for the photodynamic inactivation of pathogens in biological liquids. This paper demonstrates the chief advantage of such solid-phase systems, which is that efficient inactivation of pathogens (using influenza viruses as an example) by active forms of oxygen formed when a photosensitizer is irradiated in aqueous and biological media is combined with high photostability of the fullerene coatings and the possibility of completely extracting the photosensitizer from the biological medium after photodynamic activation.

A high-sensitivity photochemical technique has been developed for measuring to 2 in order to qualitatively and quantitatively study the sensitizing capability of various solid-phase composites that contain aggregated and nonaggregated photosensitizer molecules in an aqueous medium. The minimum error of measuring the singlet-oxygen concentration in water is 1 X 10(8) cm(-3). The operation of the technique is demonstrated, using a solid-phase photosensitizer that contains fullerene C-60 aggregates as an example. (C) 2009 Optical Society of America.

Проведено исследование стабильности оптических свойств и эффективности генерации синглетного кислорода твердофазным фотосенсибилизатором на основе фуллерена в водной суспензии и метиленовым синим в водном растворе при продолжительном интенсивном облучении видимым светом. Изменение спектров поглощения показывает убыль фуллерена за 20 мин облучения на 2% от его первоначального количества, а метиленового синего – на 19%. Динамика падения фотосенсибилизирующих свойств образцов в процессе облучения коррелирует с изменением их спектров в обоих случаях, но величина этого падения в случае твердофазного фотосенсибилизатора больше величины его спектральных изменений вследствие поверхностной природы процесса фотосенсибилизации. Исследование спектров поглощения фуллереновых покрытий показывает, что их облучение в воде и на воздухе приводит к одинаковой величине фотодеградации фуллерена. В то же время исследование с помощью техники электронного парамагнитного резонанса (ЭПР) обнаруживает различие в природе процессов, происходящих с фуллереном в воде и на воздухе.

The stability of the optical properties and the generation efficiency of singlet oxygen of a solidphase photosensitizer based on fullerene in an aqueous suspension subjected to prolonged intense irradiation with visible light are studied in comparison with a photosensitizer based on methylene blue in an aqueous solution. Changes in the absorption spectra show that, as a result of 20-min irradiation, the content of fullerene decreases by 2% from its initial value, while that of methylene blue decreases by 19%. In both cases, the dynamics of the decrease in the photosensitizing ability of the photosensitizers in the course of their irradiation correlates with the changes in their spectra, but the magnitude of this decrease in the case of the solid-phase photosensitizer is greater than the magnitude of its spectral changes because of the surface nature of the photosensitization process. The study of the absorption spectra of fullerene coatings shows that their irradiation in water or in air causes the same photodegradation of fullerene. At the same time, studies with the help of the electron spin resonance (ESR) technique reveal differences in the nature of processes undergone by fullerene in water and in air.

The relationship between the structural and photosensitizing properties of solid-phase particles of fullerene C60 in aqueous suspensions is studied using the methods of absorption spectroscopy, electron spin resonance spectroscopy (ESR), X-ray diffraction, and spectrophotometry of solutions of singlet oxygen chemical traps—histidine in combination with p-nitrosodimethylaniline. Two new variants are proposed for obtaining aqueous suspensions of particles of solid-phase fullerene whose structures are disordered and whose degrees of amorphization are 67 and 40%, respectively. It is shown that an increase in the disorder of the structure of particles in suspensions and a decrease in their average size facilitate an increase in the formation efficiency of singlet oxygen by solid-phase fullerene presumably due to an in increase in the concentration of surface localized excitons.

Singlet oxygen generation by fullerene and astralen containing surfaces and powders under visible irradiation was studied in water and organic liquids by means of (1)Delta(g) state luminescence and chemical scavenger transmittance measurements. The chemical method, pioneered for solid photosensitizers of O-1(2), allowed to measure the singlet oxygen concentration in the aqueous medium down to 10(8) cm(-3). The singlet oxygen sensitizing by the solid-phase fullerene-containing systems was found to be 100 times less effective then by fullerene in solution. The results obtained confirm the applicability of these structures in biology and medicine.

Conditions for preparing stable aqueous micellar solution of nonmodified fullerene C 60 were optimized. The size distribution of the micellar particles was determined by transmission electron microscopy, and the negative charge of the micelles was proved. The mean particle diameter appeared to be ∼2.5 times smaller than that determined by dynamic light scattering. The possibility of generation of singlet oxygen in the modified system C 60 /H 2 O was demonstrated. The 1 O 2 luminescence signal at λ = 1268 nm lasts for ∼3 μs.