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The influence of the properties of an aqueous medium on aggregation of dimegin, photoditazine, and radachlorin is comparatively studied. It is noted that the molar extinction nonlinearly depends on the concentration of photosensitizer in solution and the degree of nonlinearity is different for the pharmaceutical form of solutions and solutions prepared with the use of freeze-dried photosensitizer powders. It is shown that the use of surfactants (Pluronic F-127 and polyvinylpyrrolidone) somewhat reduces problems related to aggregation of photosensitizers under study.

The photostability of albumin complexes, Pluronic F-127 complexes and the aqueous solutions of photoditazine and dimegin were investigated. The photodegradation rate of albumin complexes was about four times faster than that of other compositions under study due to the desagregation of photosensitizers.

We compare the photostability of one porphyrin and two chlorine photosensitizers. We show that a higher photostability of dimegine compared to photoditazine and radachlorin is determined both by their different chemical natures and by the fact that the aggregation ability of porphyrin dyes is higher than that of chlorine dyes, which in the solution leads to efficient formation of dimers and higher-order complexes.

The photophysical properties of three photosensitizers—dimegine, photoditazine, and radachlorin—have been comparatively examined. For dimegine and photoditazine, two techniques have been used to measure the singlet oxygen generation quantum yields and the quenching constants of singlet oxygen by dimegine and photoditazine, as well as the dimegine fluorescence quantum yield.

Photophysical and in vitro photocytotoxicity studies were performed for the photosensitizer Dimegine, a disodium salt 2.4-di(alpha-methoxyethyl)-deuteroporphyrin-IX with very low systemic toxicity. The singlet oxygen and luminescence quantum yield were ΦΔ = 0,65 ± 0,06, and Φƒ=0,11 ± 0,01 respectively, and were independent of the excitation wavelength. The photobleaching coefficients for Dimegine dissolved in phosphate buffer (pH 7.4), and DMEM medium at concentration 2 μM/l and in phosphate buffer (pH 7.0) at concentration 10 μM/l were 16·10-5, 9·10-5 and 2·10-5 respectively. In vitro cellular distribution and photocytotoxicity was studied in two human (U87 – primary glioblastoma and HT1376 – bladder cancer) and two rat cell lines (RG2 – glioma, and AY27 – bladder carcinoma). Fluorescence microscopy analysis shows primary Dimegine accumulation as small fluorescent inclusion bodies around the nuclei, suggesting an apoptotic over a necrotic cell death mechanism. The PDT efficacy was slightly higher for the rat cell lines over the human-derived cell lines, with LD50 values of 2,5 μM/l, 2.8 μM/l, 4.5 μM/l, 2.8 μM/l using 530 nm excitation wavelength for AY27, RG2, HT1376 and U87 respectively, and 1.8 μM/l, 2 μM/l, 5 μM/l, 2.4 μM/l using 625 nm excitation wavelength for AY27, RG2, HT1376 and U87 respectively. Comparison to literature data showed that Dimegine demonstrated improved phototherapeutic characteristics comparing to PpIX-mediated PDT.

Porphyrin-based substances are modern materials applied in the design of preparations used for photodiagnostics and photodynamic therapy of cancer [1]. The wide interest to their study is drawn by its low toxicity and high selectivity to accumulation in tumor tissues. At that, the photodiagnostics task requires pronounced photoluminescent properties of porphyrins, whereas the photodynamic therapy is based on their high efficiency as regards to photosensibilization of reactive oxygen species, and especially of singlet oxygen.

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 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.

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.

Singlet molecular oxygen generation is studied by means of its NIR luminescence at light excitation by pulse, pulse‐periodic and CW sources in C60 and C70 solutions in CCl4. Singlet oxygen concentration is determined in the stationary and pulse modes of irradiation. The quenching rate constants of 1Δg state of O2 molecule by fullerene are found to be (7.2 ± 0.1)·107 M−1s−1 (C70) and < 6·104 M−1s−1 (C60). Temperature and photolytic changes in the solutions photosensibilization ability are studied using optical and ESR spectroscopy methods. A pulse liquid singlet oxygen generator is constructed and studied on the base of the C60 solution in CCl4. Production of singlet oxygen into gas phase is realized with the concentration 5·1016 cm−3.

The generation of singlet oxygen in fullerene solutions is studied by luminescence methods upon excitation by pulsed, repetitively pulsed, and continuous radiation sources. The concentration of singlet oxygen in solutions is measured in stationary and pulsed irradiation regimes. The rate constants of quenching of O2(1Δg) by fullerenes C70 and C60 in the CCl4 solution are measured to be (7.2±0.1)×107 L mol-1 s-1 and less than 6×104 L mol-1 s-1, respectively. The temperature and photolytic variations in the generation properties of the fullerene solution exposed to intense continuous radiation are studied by the methods of optical and EPR spectroscopy. Pulsed irradiation resulted in the production of singlet oxygen in suspensions of fullerene-like structures, in particular, astralenes. A liquid pulsed singlet-oxygen generator based on the fullerene solution in CCl4 is developed and studied, in which the yield of O2 (1Δg) to the gas phase at concentrations up to 5×1016 cm-3 is obtained.

The photoinduced quenching of the luminescence of singlet oxygen in solutions of C60 and C70 fullerenes in CCl4 is studied. It is shown that intense pumping of the solutions by ultraviolet and visible radiation leads to formation of relatively long-lived fullerene-oxygen complexes, which are effective quenchers of the 1Δg excited state of singlet oxygen. The behavior of these complexes depending on the experimental conditions (pumping intensity, concentration of fullerenes in the solution, and temperature) is studied. Decomposition of complexes with time is investigated. It is shown that, upon formation and gradual degradation of these complexes, the absorption spectra of the solutions change with time. The C60 fullerene is shown to be more stable to the intense pumping, its concentration being completely restored with the decomposition of the complexes. At the same time, C70 fullerene is partly irreversibly lost and the solution does not reach its initial concentration after decomposition of complexes.

Conditions for preparing stable aqueous micellar solution of nonmodified fullerene C60 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 C60/H2O was demonstrated. The 1O2 luminescence signal at λ = 1268 nm lasts for ∼3 μs.

Fullerene-containing media, including polyacrylonitrile and acrylonitrile copolymers, were tested as candidates for application in protective devices for optical limitation of the laser radiation energy generated by a YAG-Nd laser.

A study has been carried out to compare the photophysical properties of a water-soluble photosensitizer of porphyrin nature (dimegin) with photosensitizers currently used in medical practice (photoditazin and radachlorin). Results are given for an investigation of the singlet-oxygen generation efficiency by the photosensitizers when they are irradiated by an LED array (radiation wavelength 395–405 nm). The luminescence spectra of the photosensitizers irradiated by an LED (wavelength 465 nm) were investigated, and it is pointed out that dimegin has higher luminescence intensity than photoditazin and radachlorin. A study was carried out of how the block copolymer Pluronic F-127 in a complex with dimegin affects the capability of the latter to generate singlet oxygen.

The possibility of lasing in the fullerene-oxygen-iodine system with optical excitation of fullerene is studied. Laser radiation with an energy of 25 mJ and a pulse duration of 5–10 ms is obtained.

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.

The experimental investigations of photo-induced quenching of singlet oxygen luminescence in fullerene solutions (C60 and C70 in CCI4) at optical pumping have shown presence of dependence of 1gΔg 02 lifetime in a solution on initial fullerene concentration, optical pumping intensity and temperature of the solution. The increase of any of these three factors results in the reduction of the singlet oxygen lifetime in the solution, and for C70 these effects are much stronger than for C60. It is shown that at pulse optical excitation the solution C60 is stable and restores the properties some time after the influence. These effects can not be explained by only thermal mechanism, the major part is played by process of formation of fullerene-oxygen complexes which as a quencher for the state 1Δg 02. These complexes are unstable and are decomposed later into initial components. The initial fullerene C60 concentration is completely restored in the solution. The initial fullerene C70 concentration is partly restored in the solution. All these conclusions are based on the results of the study of absorption spectra of fullerene solutions before and some time after the influence on solutions of pulse optical excitation. For CW irradiation, the effects of photoinduced quenching of singlet oxygen luminescence in fullerene solutions have been studied as well. These phenomena are to be considered when developing a generators of singlet oxygen for fullerene-oxygen-iodine laser. The temperature of solution also plays an important role in the development of singlet oxygen generators. To increase the generator efficiency it is necessary to cool the solution efficiently.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The paper presents the results of experimental study of the singlet oxygen ( 1 D0 2 ) lifetime in the solution, saturated by fullerene and oxygen in CCl 4 and irradiated by optical pump with various level of power and with various spectral content. It was shown that in the case of absence of the UV component in this optical pump, i.e. in the case using of only visible spectral range, the lifetime of 1 D0 2 reaches ~ 50 ms for optical pump energy density of ~ 0/5 J/cm 2 . Pulse duration was ~ 0.5- 1 ms. Such criterion makes it possible to develop the outlook of the realistic singlet oxygen generator with optical pumping of fullerenes for pulse-repetitive and CW regimes of FOIL operation.

Singlet oxygen generation by fullerene and astralen containing surfaces and powders under visible irradiation was studied in water and organic liquids by means of 1Δg state luminescence and chemical scavenger transmittance measurements. The chemical method, pioneered for solid photosensitizers of 102, allowed to measure the singlet oxygen concentration in the aqueous medium down to 108 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.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Mechanisms of nonlinear optical limiting by fullerenes and fullerene-like nanostructures in solutions, suspensions theoretically and experimentally investigated in wide spectral range 0.3-1.1 mm. An essential contribution of photoinduced scattering to nonlinear optical limiting was demonstrated in fullerene solutions and in suspensions of fullerene-like nanostructures. It is shown than suspensions based on fullerene-like nanostructures are the most perspective for devices design with nonlinear optical protection from laser radiation (speed less than 1 ns, dynamic range 10 3 -10 4 , limiting threshold 5x10 -6 J/cm 2 , spectral range 0.3-1.1 mm, color-comfortable vision through it, i.e. the absence of limiter color.) Devices with nonlinear optical limiters are demonstrated. The computer simulation of femtosecond range optical switchers, based on fullerene containing media was performed. Fabri-Perot interferometers, containing film of fullerene film, produced by vacuum deposition and film of fullerene-polymer solid solution were investigated. Fullerene polarization nonlinearity leads to light-induced refractive index change. The probability of interferometer reflection and transmission control by low intensity signal is demonstrated.

The paper presents the results of experimental study of the singlet oxygen ( 1 DO 2 ) lifetime in the solution, saturated by fullerene and oxygen in CCl 4 and irradiated by optical pump with various level of power and with various spectral content. It was shown that in the case of absence of the UV component in this optical pump, i.e. in the case using of only visible spectral range, the lifetime of 1 DO 2 reaches ~ 50 ms for optical pump energy density of ~ 0/5 J/cm 2 . Pulse duration was ~ 0.5-1 ms. Such criterion makes it possible to develop the outlook of the realistic singlet oxygen generator with optical pumping of fullerenes for pulse-repetitive and CW regimes of FOIL operation.

The singlet oxygen generator development is the basic problem of fullerene oxygen iodine laser design. Physival principles of singlet oxygen generator on the base of solid-state fullerene-containing structures were investigated. The solid-state singlet oxygen generator is a surface of membranous structures with embedded fullerenes (fullerites) of fullerene-like nanostructures - astralenes. Singlet oxygen is generated by interaction of molecular oxygen, sorbed by the surface and fullerene-like nanostructures, photoexcited by optical pump. The singlet oxygen entrance in gas phase occurs as a desorption wave, caused by surface heating by optical pump. The effectiveness of molecular oxygen sorption by fullerene C60 and astralen depending on temperature, the extent of nanostructures heating, oxygen pressure and morphology of coating was studies.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The paper considers the physical principles of developing the fullerene-oxygen-iodine laser (FOIL) with optical (sunlight in particular) pumping. Kinetic scheme of such a laser is considered. It is shown that the utmost efficiency of FOIL may exceed 40% of the energy, absorbed by fullerenes. Presented are the experimental results of singlet oxygen generation in liquid media (solutions and suspensions) and in solid-state structures, containing either fullerenes or fullerene-like nanoparticles (FNP). In experiment was shown the possibility of the singlet oxygen transfer to the gaseous phase by means of organizing of the solution (suspension) the boiling as well as of the gasodynamic wave of desorption from the solid-state structures, containing fullerenes or FNP. We present the preliminary experimental results of pulsed generation in optically pumped FOIL with the use of primary photodissociation of iodide for preparation of the atomic iodine in the generation zone. In the experiments on FOIL generation was implemented the principle of spectral separation of optical pumping.

In this Report we present the results of theoretical and experimental investigations of photodynamics of optical limiting in the fullerene-containing media (solutions, solid-state microporous glasses and polymer layers), as well as in suspensions of fulleroid-type nanoparticles. Some prototype of nonlinear-optical devices on this base will be described as the examples.

This paper presents the results of the development of modules for protecting the eyes from laser radiation in the visible and near-IR regions. A description is given of a nonlinear-optical module with a medium based on a suspension of carbon nanoparticles in a silicone liquid, a multispectral interference filter having narrow reflection bands with minimal transmission at wavelengths of 355, 532, and 1064 nm, and a system adequate for observational devices with embedded protective elements. The combined use of the protective modules makes it possible to reduce the energy at the output of the system to a level no greater than 200 pJ when the input energy is 50 mJ and the pulse-repetition rates are as much as 10 Hz, thus ensuring the safety of the observer’s eyes.

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.

The mechanisms of nonlinear-optical limitation in suspensions of carbon and fulleroid nanoparticles have been studied experimentally and theoretically. The study was carried out in the wide spectral range of 300-1064 nm. Suspensions of fulleroid nanoparticles - astralenes - have proven to be more promising in a number of parameters (the limitation efficiency, the possibility of multiple use). © 2004 Optical Society of America

This paper discusses the physical principles involved in creating a fullerene-oxygen-iodine laser (FOIL) with optical (including solar) pumping. The kinetic layout is discussed, and it is shown that the limiting efficiency of a FOIL can exceed 40% relative to the energy absorbed by the fullerenes. Experimental results of the lasing of singlet oxygen in liquid media (solutions and suspensions) and in solid-state structures containing both fullerenes and fullerenelike nanoparticles (FLNs) are presented. It is experimentally shown to be possible to release oxygen in the vapor phase by organizing the boiling of a solution (suspension), as well as by a gasdynamic desorption wave from solid-state FLN- or fullerene-containing structures. Preliminary experimental results are presented of the pulsed lasing of a FOIL with optical pumping, using the initial photodissociation of iodide to provide atomic iodine in the lasing zone. The principle of spectral separation of optical pumping is implemented in experiments on the lasing of a FOIL.

Immobilization of alpha-amylase from Bacillus subtilis by adsorption on carboxyl polyelectrolytes, copolymers of methacrylic acid and ethylene glycol dimethacrylate, was being investigated depending on the structure of the polymeric matrix. It is demonstrated that cation exchange resins can be successfully used for reversible sorption and immobilization of alpha-amylase. It was found that the more heterogeneous the structure of the polymeric carrier, the higher is reversibility of the enzyme adsorption. The isothermic process of Bac. subtilis alpha-amylase adsorption on copolymers of different structures was studied as well. The equilibrium of the sorption system was proved to be true.