A study is performed of the inactivation of planktonic bacteria Escherichia coli and Bacillus subtilis by acoustic shock waves generated by a nanosecond laser pulse that causes rapid local heating, growth, and collapse of vapor bubbles in a physiological saline with bacteria containing organic dyes as thermosensitizers. The role of strong electronically excited states of dyes in the local heating of a medium is shown. The dependence of the efficiency of microorganism inactivation on the type and concentration of dyes, the power density of the exciting radiation, and the distance from the source of shock wave generation is studied.

A methodology for the formation of molecular clusters of silver in silicate nanoporous glasses has been developed. Composite materials containing molecular clusters of silver, silver nanoparticles and zinc oxide have been synthesized. The synthesis was carried out by impregnation of porous glasses in aqueous solutions of silver and zinc nitrates stabilized with high-molecular polyvinylpyrrolidone, followed by heat treatment of samples for decomposition of metal nitrates and polymer. Spectral-luminescent properties of composites have been investigated.

The photoexcitation energy transfer in donor–acceptor (DA) systems formed from a mixture of semiconductor polymer poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) with fullerene C 60 and endohedral metallofullerene Ho@C 82 have been investigated. It is established that the migration of excitons between polymer segments significantly affect the quenching of MEH-PPV luminescence. The Forster radii of nonradiative energy transfer are estimated for the DA systems under study. It is shown that the DA system formed using endohedral metallofullerenes is most efficient. Model photovoltaic cells with different C 60 and Ho@C 82 doping levels are formed based on MEH-PPV. The spectral sensitivity of photovoltage and kinetics of rise in the photovoltage signal under pulsed irradiation are measured for the formed cells. The charge carrier mobility in the polymer composites under study is estimated. It is established that a change in the endohedral metallofullerene concentration within 1–2% makes it possible to change the effective free-carrier mobility of the polymer heterojunction.

The photoexcitation energy transfer was studied in donor-acceptor systems (DA) formed from a mixture of the semiconductor polymer poly [2-methoxy-5- (2`-ethylhexyloxy) -1,4-phenylenevinylene] (MEH-PPV) with C60 fullerene and endohedral metallofullerene Ho@C82. A significant effect of the exciton migration between the polymer units on the quenching of MEH-PPV luminescence has been established. The Foerster radii of nonradiative energy transfer for the investigated DA systems are estimated. It is shown that the DA system formed using endohedral metallofullerenes is the most effective. Based on MEH-PPV, model photovoltaic cells with different doping levels C60 and Ho@C82 were formed. For the formed cells, the spectral sensitivity of the Photo-EMF and the kinetics of the increase in the Photo-EMF signal under pulsed irradiation were measured. The mobility of charge carriers in the studied polymer composites was estimated. It was found that a change in the concentration of endohedral metallofullerene within 1-2% allows you to change the effective mobility of free carriers of the polymer heterojunction.

This study demonstrates the susceptibility of the Escherichia coli and Bacillus subtilis planktonic bacteria to inactivation by shock acoustic waves that arise from the rapid formation and collapse of vapor bubbles in a medium locally heated to its boiling point. Local heating of the medium occurred due to heat release through the relaxation of highly excited electronic states of exogenous molecules of organic dyes. Dye molecules were excited by nanosecond laser pulses. Highly excited electronic states were formed as a result of stepwise absorption of two quanta of laser radiation. The dependence of the efficiency of microorganism inactivation on the dye concentration, excitation power density, and the distance from the shock wave source was studied.

A method for the physicochemical modification of the structure of gelatinous films is proposed. For this purpose, molecular-recognition-based self-assembly was used: the formation of (bio)polymolecular complexes between gelatin and chitosan owing to the interactions of the main amino acid residues in gelatin and acidic amino groups in the structure of chitosan (cooperative polyelectrolyte interaction). The use of a gelatin–chitosan matrix made it possible to significantly increase the luminescence yield of the dyes introduced into the biopolymer. This was due to the more efficient filling of the corresponding binding gelatin sites with dye molecules and, consequently, minimization of the concentration quenching of fluorescence. In the film samples of gelatin–chitosan matrix–dye, effective superluminescence of sulforhodamine B was achieved.

The dynamics of the consumption of oxygen during photodynamic processes and the subsequent restoration of its concentration in malignant tumors and healthy tissues of mice were studied in vitro by the kinetics of long-term luminescence of xanthene dyes. To assess changes in the oxygen concentration in tissues, delayed fluorescence can be used due to singlet–triplet annihilation of singlet oxygen and a sensitizer in the triplet state. Upon periodic pulse excitation of sensitizers, reversible quenching of delayed fluorescence was detected in tumors, which is associated with a decrease in the amount of oxygen in the tissues during photodynamic processes. A method for visualizing the restoration of the initial oxygen concentration in tissues is proposed.

The dynamics of oxygen consumption during photodynamic processes and its subsequent restoration in malignant tumors and healthy tissues of mice were studied in vitro by kinetics of long-term luminescence of xanthene dyes. It was shown that to estimate changes in tissue oxygen tension, specific type of delayed fluorescence can be used which caused by singlet-triplet annihilation of singlet oxygen and a sensitizer in triplet state. In tumors under pulse excitation of sensitizers, reversible quenching of delayed fluorescence was observed, which is associated with a decrease in the tissue oxygen tension during photodynamic processes. Method for visualizing the restoration of the initial oxygen level in tissues after photodynamic action is proposed.

Abstract—The results of a study of photoinactivation of bacteria during stimulation of sensitizers with nanosecond laser pulses with a power density within 1–30 MW/cm2 are presented. The irreversible damage to living cells by shock waves developed during the formation and collapse of vapor bubbles in locally heated microregions of the medium is discussed. The local heating of the medium occurred due to heat release during nonradiative relaxation of high electronic states of sensitizer molecules.

Abstract—The kinetics of delayed fluorescence and phosphorescence of xanthene dyes in mouse tissues under the pulse-periodic excitation of molecules was studied in vivo and in vitro. The advantages of continuous monitoring of oxygen content in tissues by the kinetics of delayed fluorescence caused by singlet–triplet annihilation of singlet oxygen with triplet excitation of fluorophore are demonstrated. A method is proposed for determining the time of recovery of the concentration of oxygen consumed in tissues in vivo and in vitro during photodynamic processes.

Long-term luminescence of organic dyes (xanthene dyes, halogen substituted fluoroscein) was used for an in vitro study of the photodynamic effect of exogenic probes in malignant tumors and healthy tissues of mice. It is shown that the photodynamic activity of oxygen and the dynamics of its concentration in tissues can be estimated from the delayed fluorescence of exogenic probes caused by singlet–triplet annihilation of singlet oxygen and excited triplet states of the molecules of photosensitizer dyes. It is found that quenching of long-term luminescence of photosensitizers significantly differs in tumors and normal tissues.

The formation of endohedral metallofullerene clusters with Y, Gd, and Ho in an N,N-dimethylformamide solution and on a mica substrate surface has been investigated using static and dynamic light scattering and atomic force microscopy, respectively. It has been found that the size distribution of the clusters depends on the concentration of endohedral metallofullerenes and on the exposure time of the solution. It has been shown that the clusters are resistant to high temperatures and ultrasound effects. The concentration of endohedral metallofullerenes at which only single clusters are formed in the solutions has been determined. It has been established that an increase in the concentration of endohedral metallofullerenes leads to the agglomeration of single clusters. The fractal dimension has been estimated, and the zeta potential of endohedral metallofullerene clusters has been measured.

The features of delayed fluorescence (DF) and phosphorescence in erythrosine stained healthy and cancer-diseased mammary gland tissues of BYRB-line mice were investigated in vitro. Thermoactivated delayed fluorescence (TDF), triplet-triplet annihilation (TTA) and originated from singlet-triplet annihilation (STA) delayed fluorescence are investigated as competing channels of radiative relaxation of the triplet states of erythrosine. The dominant role of diffusive-mobile molecular oxygen in deactivation of triplet-excited long-live states of the dye molecules in cells is determined. The previously not described phenomenon of light quenching of DF under pulsed laser irradiation (light quenching of DF, LQDF) in stained tissue was revealed. LQDF is increased if the energy of excited pulses is rise and their sequence period is decreased. The DF depletion disappears if time interval between pulses in the series is >5s. This phenomenon is due two process competition: fast consumption of singlet oxygen by oxidation of cell organelles right after laser pulse excitation and slow diffusive recovery of oxygen concentration in the pause between the pulses. Statistically valid distinction between DF characterization as well as LQDF erythrosine extent in healthy and pathological tissues was established. The use of this phenomenon will greatly simplify the determination of radiation "dose" in photodynamic therapy (PDT) directly during the treatment session.

Установлены закономерности кинетики замедленной флуоресценции и фосфоресценции экзогенных флуорофоров (молекул органических красителей) в биологических тканях. Обсуждены отличия кинетики замедленной флуоресценции окрашенных эритрозином образцов здоровых и патогенных тканей in vitro.