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OBJECTIVE There is currently no consensus regarding the appropriate lower instrumented vertebra (LIV) for multilevel posterior cervical fusion (PCF) constructs between C7 and crossing the cervicothoracic junction (CTJ). The goal of the present study was to compare postoperative sagittal alignment and functional outcomes among adult patients presenting with cervical myelopathy undergoing multilevel PCF terminating at C7 versus spanning the CTJ. METHODS A single-institution retrospective analysis (January 2017–December 2018) was performed of patients undergoing multilevel PCF for cervical myelopathy that involved the C6–7 vertebrae. Pre- and postoperative cervical spine radiographs were analyzed for cervical lordosis, cervical sagittal vertical axis (cSVA), and first thoracic (T1) vertebral slope (T1S) in two randomized independent trials. Modified Japanese Orthopaedic Association (mJOA) and Patient-Reported Outcomes Measurement Information System (PROMIS) scores were used to compare functional and patient-reported outcomes at the 12-month postoperative follow-up. RESULTS Sixty-six consecutive patients undergoing PCF and 53 age-matched controls were included in the study. There were 36 patients in the C7 LIV cohort and 30 patients in the LIV spanning the CTJ cohort. Despite significant correction, patients undergoing fusion remained less lordotic than asymptomatic controls, with a C2–7 Cobb angle of 17.7° versus 25.5° (p < 0.001) and a T1S of 25.6° versus 36.3° (p < 0.001). The CTJ cohort had superior alignment corrections in all radiographic parameters at the 12-month postoperative follow-up compared with the C7 cohort: increase in T1S (ΔT1S 14.1° vs 2.0°, p < 0.001), increase in C2–7 lordosis (ΔC2–7 lordosis 11.7° vs 1.5°, p < 0.001), and decrease in cSVA (ΔcSVA 8.9 vs 5.0 mm, p < 0.001). There were no differences in the mJOA motor and sensory scores between cohorts pre- and postoperatively. The C7 cohort reported significantly better PROMIS scores at 6 months (22.0 ± 3.2 vs 11.5 ± 0.5, p = 0.04) and 12 months (27.0 ± 5.2 vs 13.5 ± 0.9, p = 0.01) postoperatively. CONCLUSIONS Crossing the CTJ may provide a greater cervical sagittal alignment correction in multilevel PCF surgeries. However, the improved alignment may not be associated with improved functional outcomes as measured by the mJOA scale. A new finding is that crossing the CTJ may be associated with worse patient-reported outcomes at 6 and 12 months of postoperative follow-up as measured by the PROMIS, which should be considered in surgical decision-making. Future prospective studies evaluating long-term radiographic, patient-reported, and functional outcomes are warranted.

The development of innovations has an inevitable impact on the ability of organizations to innovate. Reducing costs and increasing the quality of services force organizations to adapt to the ever-changing environment constantly and adequately. The extremely fast development of information and communication technologies gives grounds to believe that innovations will be a key factor in achieving competitiveness and will continue to be a major challenge for companies in the future. This article presents detailed information on a study of the innovation capability of organizations that belong to the industrial sector “Information and Communication Technologies” (ICT) in Bulgaria. A statistically substantiated comparative analysis of the characteristics of the innovation ability is done. The subject and object of the research are presented. Both methodology and logic for testing the research hypothesis are described in detail. The obtained results confirm the main research thesis related to the importance and role of industrial clusters for increasing the innovation capability of organizations.

Four mestranol moieties were chemically linked to Zn(II) phthalocyanine (4) by cycloaddition “Click” reaction using a tetra-azidoethoxy substituted Zn(II)-phthalocyanine (3). The alkyl-azido coupling reaction was realized between azido groups of 3 and alkyl group of mestranol. The alkylation reaction was carried out to obtain cationic Zn(II) phthalocyanine derivative (5). The new compounds were chemically characterized by the known analytical methods. The absorption and fluorescence properties were studied in comparison. The absorption maxima of phthalocyanines 3, 4 and 5 were recorded at approx. shifts of 8 - 12 nm in the far- red region (680 - 684 nm) and the fluorescence maxima (692 - 693 nm) as compared to unsubstituted ZnPc (672 nm, 680 nm) in DMSO. The studies of singlet oxygen generation of 3, 4 and 5 showed relatively high values such as 0.52 for 3; 0.51 for 4 and 0.46 for 5. The fluorescence lifetime of 3.15 ns (3), 3.25 ns (4) and 3.46 ns (5) were determined with lower than the value than for the used standard ZnPc (3.99 ns). The high photo stability was observed for compounds 3, 4 and 5. In addition, the photosensitized oxidation of cholesterol was compared for 3 and 4 with much lower values of oxidation potential than for unsubstituted ZnPc which suggests that the substitution groups influenced on the photooxidation index of the target molecule.

The hydro-distilled leaves of Pistacia lentiscus are considered as an agricultural residue and of no commercial value yet. In this study, chromatographic purification of a methanolic fraction of P. lentiscus L. (lentisk) distilled leaves yielded pure compounds, including Quercitrin (QUE) and Loliolid (LOL) which are characterized, for the first time, in the lentisk leaves’ residue. The inhibitory potential of QUE and LOL was investigated against tyrosinase and acetylcholinesterase activities using enzymatic assays and lysozyme fibrillation through Thioflavin-T fluorescence assay. Their binding mode to Bovine Serum Albumin (BSA) was also assessed by several spectroscopic analyses. Results show that QUE was more potent to inhibit enzyme activity than LOL. Besides, the Thioflavin-T assay confirmed that only QUE was able to block the fibril formation at a concentration of 25 μg/mL. Furthermore, the BSA quenching mechanism by QUE and LOL is a static process with conformational changes in BSA. Interestingly, our findings may provide novel insights into the potentiality of lentisk to be used as a bioresource for the generation of Quercitrin and Loliolid which can be commercially exploited in the field of cosmeceuticals and nutraceuticals.

Photodynamic therapy (PDT) is a curative method, firstly developed for cancer therapy with fast response after treatment and minimum side effects. Two zinc(II) phthalocyanines (3ZnPc and 4ZnPc) and a hydroxycobalamin (Cbl) were investigated on two breast cancer cell lines (MDA-MB-231 and MCF-7) in comparison to normal cell lines (MCF-10 and BALB 3T3). The novelty of this study is a complex of non-peripherally methylpyridiloxy substituted Zn(II) phthalocyanine (3ZnPc) and the evaluation of the effects on different cell lines due to the addition of second porphyrinoid such as Cbl. The results showed the complete photocytotoxicity of both ZnPc-complexes at lower concentrations (

The antimicrobial multidrug resistance (AMR) of pathogenic bacteria towards currently used antibiotics has a remarkable impact on the quality and prolongation of human lives. An effective strategy to fight AMR is the method PhotoDynamic Therapy (PDT). PDT is based on a joint action of a photosensitizer, oxygen, and light within a specific spectrum. This results in the generation of singlet oxygen and other reactive oxygen species that can inactivate the pathogenic cells without further regrowth. This study presents the efficacy of a new Pd(II)- versus Zn(II)-phthalocyanine complexes with peripheral positions of methylpyridiloxy substitution groups (pPdPc and ZnPcMe) towards Gram-negative bacteria

The photodynamic impact of water-soluble zwitterionic zinc phthalocyanines (ZnPc1–4) was studied on pathogenic bacterial strains after specific light exposure (LED 665 nm). The structural differences between the studied ZnPc1–4 are in the positions and the numbers of substitution groups as well as in the bridging atoms (sulfur or oxygen) between substituents and macrocycle. The three peripherally substituted compounds (ZnPc1–3) are tetra-2-(N-propanesulfonic acid)oxypyridine (ZnPc1), tetra-2-(N-propanesulfonic acid)mercaptopyridine (ZnPc2), and octa-substituted 2-(N-propanesulfonic acid)mercaptopyridine (ZnPc3). The nonperipherally substituted compound is tetra-2-(N-propanesulfonic acid)mercaptopyridine (ZnPc4). The uptake and localization capability are studied on Gram (+) Enterococcus faecalis and Gram (−) Pseudomonas aeruginosa as suspensions and as 48 h biofilms. Relatively high accumulations of ZnPc1–4 show bacteria in suspensions with different cell density. The compounds have complete penetration in E. faecalis biofilms but with nonhomogenous distribution in P. aeruginosa biomass. The cytotoxicity test (Balb/c 3T3 Neutral Red Uptake) with ZnPc1–4 suggests the lack of dark toxicity on normal cells. However, only ZnPc3 has a minimal photocytotoxic effect toward Balb/c 3T3 cells and a comparable high potential in the photoinactivation of pathogenic bacterial species.

Octa-(4-tyrosylamido) phenyl substituted Zn(II) phthalocyanine (ZnPcTyr8) was synthesized and characterized as potential photosensitizer for photodynamic therapy (PDT). The new ZnPcTyr8 was evaluated in comparison to recently synthesized tetra-(4-tyrosylamido) phenyl substituted Zn(II) phthalocyanine (ZnPcTyr) and used as a standard unsubstituted Zn(II) phthalocyanine (ZnPc). The photophysical properties of absorption and fluorescence, and photochemical properties of singlet oxygen generation and photostability as well as in vitro photocytotoxicity property were investigated. The irradiation from a light-emitting diode (LED 665 nm) with a dose of 50 J cm−2 and a fluence of 60 mW cm−2 was applied. The obtained results suggested improved photophysicochemical properties of singlet oxygen generation for tyrosine-conjugated Zn(II)-phthalocyanines. In addition the tyrosine substitution to ZnPc is liable for gentle photocytotoxicity which is in contrast to the harsh phototoxic effect determined for ZnPc on tumor and normal cell lines. Among both tyrosine substituted Zn(II) phthalocyanines, a novel ZnPcTyr8 has advantages of water solubility and proper values of the main photophysicochemical properties responsible for PDT efficacy.

A novel rotary switch, overcoming the disadvantages of hydrazone based switches with competitive proton acceptor sub-rotors, has been designed. The new compound contains a pyridyl ring and a COOH group as sub-rotors, which provides engagement of the pyridyl nitrogen atom and leads to the existence of a single isomer in the ground state. The availability of acidic functionality in the rotor creates conditions for excited state intramolecular proton transfer (ESIPT), which exhibits anti-Kasha behavior.

The goal of our research was to assess the vascularization degree of tumor to predict the efficiency of plasmonic photothermal therapy (PPT) and photodynamic therapy (PDT) in tumor-bearing rats. Before any treatment, 3D Doppler ultrasound imaging was used for assessment of the vascularization degree of transplanted rat cholangiocarcinoma. For PPT, the gold nanorods with aspect ratio of 4:1, functionalized with thiolated polyethylene glycol, were used. After multiple fractional intravenous (IV) injections in rats with cholangiocarcinoma, the tumours were irradiated through the skin by an 808-nm NIR diode laser at a power density of 2.3 W/cm2 for 15 min. For PDT, galactose – Luphthalocyanine, as a photosensitizer, was applied by intratumoural injection, in a dose of 2 mg/kg. Then, tumors were irradiated through the skin by 670 nm-diode laser source with power density 200 mW/cm2 applied for 1000 sec in three non-overlapping zones covering whole tumour surface to obtain a total irradiation dose of 200 J/cm2 for each lesion. The withdrawal of the animals from the experiment and sampling of tissues for morphological study were performed before and 72 hrs after PPT and PDT. The vascular microdensity in tumors was assessed on histological sections as vessel counts or vessel area per unit of assessed tumor area. It was shown that efficiency of PPT and PDT therapy was mostly due to the sufficient accumulation of photothermosensitizers in the tumor, therefore preliminary assessment of tumor vascularization degree was necessary before starting a therapy.

Porphyrins used as photosensitizers are accumulated selectively in glioblastoma cells due to the latter heme metabolism disorders and could be used effectively for intraoperative fluorescence staining of the tumor formation and differentiation from normal brain parenchyma. The aim of this work was to investigate the photodynamic properties of 5-ALA/PpIX on stem cell cultures isolated from glioblastoma. Supernatant samples of photosensitizer-treated cell lines were used for evaluation of photosensitizers’ accumulation in the cell lines investigated using excitation in the spectral ranges of Soret’ band (360 – 410 nm) and Q-band (600 – 650 nm). The emission detected was used to evaluate the efficacy of the photodynamic treatment during PDT irradiation inducing apoptosis and necrosis processes in cell lines treated with photosensitizers. Several variables were studied, such as histochemical and genetic variants of glioblastoma, and various photosensitizers’ concentrations and light-emitting parameters. The results of this in vitro work will be used as the basis for a further in vivo application on animal models of glioblastoma with applying irradiation using intracranial light sources and for a subsequent transfer of the obtained protocols of photodynamic treatment of glioblastoma lesions in such model systems for the needs of human medicine.

Immobilization of proteins on a surface plasmon resonance (SPR) transducer is a delicate procedure since loss of protein bioactivity can occur upon contact with the untreated metal surface. Solution to the problem is the use of an immobilization matrix having a complex structure. However, this is at the expense of biosensor selectivity and sensitivity. It has been shown that the matrix-assisted pulsed laser evaporation (MAPLE) method has been successfully applied for direct immobilization (without a built-in matrix) of proteins, preserving their bioactivity. So far, MAPLE deposition has not been performed on a gold surface as required for SPR biosensors. In this paper we study the impact of direct immobilization of heme proteins (hemoglobin (Hb) and myoglobin (Mb)) on their bioactivity. For the purpose, Hb and Mb were directly immobilized by MAPLE technique on a SPR transducer. The bioactivity of the ligands immobilized in the above-mentioned way was assessed by SPR registration of the molecular reactions of various Hb/Mb functional groups. By SPR we studied the reaction between the beta chain of the Hb molecule and glucose, which shows the structural integrity of the immobilized Hb. A supplementary study of films deposited by FTIR and AFM was provided. The experimental facts showed that direct immobilization of an intact molecule was achieved.

Abiotic synthesis of nucleobases and amino acids is of critical importance as it sheds light on potential prebiotic chemical reactions. During thermal decomposition of formamide in vacuum conditions, purine, cytosine, adenine, hypoxanthine, uracil, pterin, urea, urocanic acid, glycine, alanine and norvaline were detected. The compounds were obtained without catalyst by heating at 100-180 °C or microwave heating of formamide. Reaction network of self-catalyzed chemical reactions is suggested, showing how from only one parent molecule, nucleobases, urea and the amino acid glycine can be produced. The reaction pathways are theoretically determined using SCS-MP2 calculations.Communicated by Ramaswamy H. Sarma.

The target-specific drug release which is depending on the pH of the medium appears precious approach for increasing of drug selectivity and further efficacy in photodynamic diagnosis (PDD) and therapy (PDT) of cancer. A strongly hydrophobic Zn (II) phthalocyanine (ZnPc) along with its liposomal formulates belongs to the clinically approved phthalocyanines for cancer photodiagnosis PDD and PDT. Nevertheless closed to the ideal photo-physicochemical properties the planar molecular structure of ZnPc easily forms aggregates which finally limit the phototoxic effect. Different strategies are on hand, all aiming to minimize the formation of photo-inactive associates. At present time, the polymeric carrier systems are still under development as carrier systems for biomedical applications. The present work evaluated the efficiency of two recently proposed graft - copolymers namely polyimide (PI)-graft-polymethacrylic acid (PAT2 and PAT3) as vehicles of hydrophobic ZnPc. The potential of the proposed polymeric brushes with great number of carboxylic groups, for conformational changes in different pH media, can be used for ZnPc release as studied by fluorescence spectroscopy. Complexes developed were investigated in vivo on rat model system of gastric carcinoma lesions for photodiagnosis and photodynamic treatment of neoplasia and compared with the application of ZnPcs solely. The contrast achieved of the fluorescence detection using polymer brushes - phthalocyanine conjugate is about twice higher that standard applied photosensitizer using same protocol and doses of application. The photodynamic treatment efficacy was also significantly improved allowing to receive full response using doses of 0,5-1 mg/kg of the conjugates. |To obtain same efficiency for the ZnPc PDT in the gastric lesions treated drug doses of 1,5-2 mg/kg had to be applied. Initially detected fluorescence signal and photo-bleaching dynamics were used for the monitoring of the processes of accumulation and photodynamic treatment processes.

The new generations of photoactive compounds, which are derivatives of already well-established groups of photosensitizers, together with the modern light sources in the spectral region of their activation and in the PDT window range, are emerging as a reliable phototherapy approach for tumour treatment with higher efficiency. The substitution of a highly hydrophobic phthalocyanine with galactose units could improve the solubility and to decrease significant aggregation in polar solvents. The control group of rats with transplanted cholangiocarcinoma without any treatment was used for comparison of PDT effectiveness. In the second group the white outbred male rats with cholangiocarcinoma lesions were treated using Zn-phthalocyanine, as a typical representative of phthalocyanine photosensitizers with known photodynamic properties and the third group of animals was treated with galactose – Lu-phthalocyanine, as a novel derivative from the same family with two specific differences – presence of galactose and replacing of Zn(II) with Lu(III) ion. To compare the PDT effectiveness of both compounds the same drug doses were applied - 2 mg/kg, applied by intratumoural injection. Diode laser source at 670 nm, on 50 mW output power with power density applied 200 mW/cm2 was applied for 1000 sec to obtain total irradiation dose of 200 J/cm2 for each lesion. 3 days after treatment, the animals were withdrawn from the experiment. Tissue from the central zone and periphery of the tumor was taken for morphological examination and fixed in 10% formalin. Serial paraffin sections were stained with hematoxilin-eosin and by immunohistochemical staining with antibodies to proliferation marker Ki-67 and apoptosis marker BAX. After photodynamic therapy, pronounced necrobiotic changes in combination with an inflammatory reaction were developed at the central zone of tumors. The dystrophic changes, reduction of proliferation and development of apoptosis in tumor cells were observed on tumor periphery as well.

Four novel tetra non-peripheral 2-hydroxypyridine substituted palladium (II) and nickel (II) phthalocyanines and their quaternized derivatives were synthesized. The phthalocyanines were fully characterized by different spectroscopic methods such as UV-Vis, FT-IR, 1H NMR and MALDI-TOF mass spectrometry. The quaternized phthalocyanines showed solubility in DMSO and water within a wide concentration range and with lack of aggregation behavior. The singlet oxygen generation properties were determined for quaternized phthalocyanine complexes in DMSO, water, and water + TritonX 100 solutions. The uptake capability and in vitro photodynamic activity studies performed on two pathogenic bacteria namely Gram (+) Methicillin-resistant Staphylococcus aureus (MRSA) and Gram (-) Aeromonas hydrophila suggested good potential of palladium (II) phthalocyanine complex (5) for the uptake and inactivation of planktonic cultured bacteria. Significant localization of water-soluble Pd(II) phthalocyanine complex was observed for MRSA biofilms. However, this resulted in low efficiency of pathogen inactivation. The newly synthesized nickel (II) phthalocyanine (6) showed lack of inactivation towards both bacterial strains under the applied mild treatment conditions.

Photodynamic inactivation (PDI) has been featured as an effective strategy in the treatment of acute drug-resistant infections. The efficiency of PDI was evaluated against three periodontal pathogenic bacteria that were tested as drug-resistant strains. In vitro studies were performed with four water-soluble cationic Zn(II) phthalocyanines (ZnPc1–4) and irradiation of a specific light source (light-emitting diode, 665 nm) with three doses (15, 36 and 60 J/cm2). The well detectable fluorescence of ZnPcs allowed the cellular imaging, which suggested relatively high uptakes of ZnPcs into bacterial species. Complete photoinactivation was achieved with all studied ZnPc1–4 for Enterococcus faecalis (E. faecalis) at a light dose of 15 J/cm2. The photodynamic response was high for Prevotella intermedia (P. intermedia) after the application of 6 μM of ZnPc1 and a light dose of 36 J/cm2 and for 6 μM of ZnPc2 at 60 J/cm2. P. intermedia was inactivated with ZnPc3 (4 log) and ZnPc4 (2 log) with irradiation at an optimal dose of 60 J/cm2. Similar photoinactivation results (2 log) were achieved for Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) treated with 6 μM ZnPc1 and ZnPc2 at a light dose of 60 J/cm2. The study suggested that PDI with quaternized Zn(II) phthalocyanines and specific light irradiation appears to be a very useful antimicrobial strategy for effective inactivation of drug-resistant periodontal pathogens.

Regretfully, because of her sudden demise, Assoc. Prof. Ekaterina Borisova is no longer amongst us. COVID-19 pulled away a brilliant scientist during the peak of her scientific career (see Fig. 1). All authors would like to express deepest condolences and sincere support to her family, friends, relatives and colleagues! We, therefore, rightfully commemorate her dedicated and devoted contribution to biophotonics, her readiness to always support, help, motivate and inspire all her colleagues and collaborators., We would like to acknowledge the support from the National Science Fund of the Bulgarian Ministry of Education and Science (NSFB-MES) under all current projects involving Assoc. Prof. Ekaterina Borisova, which are grant numbers: #DN 18-8; #КP06-N29/11/18.12.18; #KP06-N28/11/14.12.2018; #KP06-Russia-9/2020; #KP-06-N23/8; #KP-06/N38/13; #KP06-India-8/07.08.2019; #KP-06-KOST-6. Also, projects under NRRI #DO1-401/18.12.2020 and #D01-392/18.12.2020.

In a series of previous studies, we demonstrated that the photodynamic therapy (PDT), as a widely used tool for treatment of glioblastoma multiforme (GBM), also site-specifically opens the blood&ndash, brain barrier (BBB) in PDT-dose and age-related manner via reversible disorganization of the tight junction machinery. To develop the effective protocol of PDT-opening of the BBB, here we answer the question of what kind of photosensitizer (PS) is the most effective for the BBB opening. We studied the PDT-opening of the BBB in healthy mice using commercial photosensitizers (PSs) such as 5-aminolevulenic acid (5-ALA), aluminum phthalocyanine disulfonate (AlPcS), zinc phthalocyanine (ZnPc) and new synthetized PSs such as galactose functionalized ZnPc (GalZnPc). The spectrofluorimetric assay of Evans Blue albumin complex (EBAC) leakage and 3-D confocal imaging of FITC-dextran 70 kDa (FITCD) extravasation clearly shows a revisable and dose depended PDT-opening of the BBB to EBAC and FITCD associated with a decrease in presence of tight junction (TJ) in the vascular endothelium. The PDT effects on the BBB permeability, TJ expression and the fluorescent signal from the brain tissues are more pronounced in PDT-GalZnPc vs. PDT-5-ALA/AlPcS/ZnPc. These pre-clinical data are the first important informative platform for an optimization of the PDT protocol in the light of new knowledge about PDT-opening of the BBB for drug brain delivery and for the therapy of brain diseases.

The development of ionic liquids based on active pharmaceutical ingredients (API-ILs) is a possible solution to some of the problems of solid and/or hydrophobic drugs such as low solubility and bioavailability, polymorphism and an alternative route of administration could be suggested as compared to the classical drug. Here, we report for the first time the synthesis and detailed characterization of a series of ILs containing a cation amino acid esters and anion ketoprofen (KETO-ILs). The affinity and the binding mode of the KETO-ILs to bovine serum albumin (BSA) were assessed using fluorescence spectroscopy. All compounds bind in a distance not longer than 6.14 nm to the BSA fluorophores. The estimated binding constants (KA) are in order of 105 L mol&minus, 1, which is indicative of strong drug or IL-BSA interactions. With respect to the ketoprofen-BSA system, a stronger affinity of the ILs containing l-LeuOEt, l-ValOBu, and l-ValOEt cation towards BSA is clearly seen. Fourier transformed infrared spectroscopy experiments have shown that all studied compounds induced a rearrangement of the protein molecule upon binding, which is consistent with the suggested static mechanism of BSA fluorescence quenching and formation of complexes between BSA and the drugs. All tested compounds were safe for macrophages.

An intelligent autonomous control unit for dimmable LED lighting has been developed. A group of street lights, for a street, a neighborhood or a village, is switched on and off by an astronomical calendar relay. Each luminaire has a small control system with intelligent self-tuning during the luminaire's operation. During operation, the luminous flux of the illuminator changes according to a given algorithm and corrects the aging of the sources by the accumulated hours of work.

Gastrointestinal cancerous lesions were induced in laboratorial animals using prolonged exposure to social (overpopulation) and chemical stress (nitrosamine diet), mimicking typical stress factors for humans in the big cities. Twenty laboratorial rats with developed stress-induced neoplasia in gastrointestinal tract were used. Three of them formed control group - without application of exogenous contrast fluorescent marker. Exogenous fluorescent spectroscopic measurements were used to evaluate gastrointestinal tract (GIT) neoplasia development noninvasively using excitation at 405 nm and emission was detected in the region of 500-850 nm using microspectrometer. We used as exogenous fluorescent marker protoporphyrin IX applying its precursor delta aminolevulinic acid in a dose of 20mg/kg, in laboratorial rats with stress-induced neoplasia. Spectroscopic analysis of primary gastric tumours and their metastases spreading in rats’ liver was carried out on animals in vivo, as excitation and emission light were delivered by fiberoptic probe 6+1 to the organs investigated during open surgery procedure. Biochemical indicators detected malignant alterations presence in GIT were also evaluated and used as complementary indices for lesions’ growth. Fluorescent observation using exogenous fluorophore addressed the exact area and borders of neoplastic lesions in stomach and liver. In some cases in inflammatory areas significant accumulation of delta-ALA had place, which lead to false-positive fluorescent signal of protoporphyrin IX in these tissues. Photodiagnostics accuracy of 93% was reached for cancerous cases and 87% for gastric pre-cancer lesions evaluation. Very good correlation between fluorescence data and histology examination of the lesions investigated was achieved as well.

The result of photodynamic action significantly depends on the density of the light dose absorbed by the photosensitizer. The efficiency of using light to excite photosensitizer molecules and minimization of its loss plays an important role in ensuring the overall success of the process. When carrying out photodynamic treatment of thin sensitized layers (such as inactivation of surface pathogens or in vitro screening studies of photosensitizers), only a part of the light dose is absorbed in the layer, while a significant part is lost, especially at low concentrations of the photosensitizer. In this work, we evaluate the decrease in absorbed light dose depending on the extinction and concentration of the photosensitizer in a thin sensitized layer, the shape of its absorption spectrum, and the shape of the excitation light source spectrum. It was found out that a significant loss of the absorbed dose occurs upon excitation of photosensitizers, especially with low extinction, when using light sources with a broad emission spectrum. This loss must be taken into consideration when predicting the results of photodynamic exposure and optimizing its tactics.

Various metal phthalocyanines have been studied for their capacity for photodynamic effects on viruses. Two newly synthesized water-soluble phthalocyanine Zn(II) complexes with different charges, cationic methylpyridyloxy-substituted Zn(II)- phthalocyanine (ZnPcMe) and anionic sulfophenoxy-substituted Zn(II)-phthalocyanine (ZnPcS), were used for photoinactivation of two DNA-containing enveloped viruses (herpes simplex virus type 1 and vaccinia virus), two RNA-containing enveloped viruses (bovine viral diarrhea virus and Newcastle disease virus) and two nude viruses (the enterovirus Coxsackie B1, a RNA-containing virus, and human adenovirus 5, a DNA virus). These two differently charged phthalocyanine complexes showed an identical marked virucidal effect against herpes simplex virus type 1, which was one and the same at an irradiation lasting 5 or 20 min (Δlog=3.0 and 4.0, respectively). Towards vaccinia virus this effect was lower, Δlog=1.8 under the effect of ZnPcMe and 2.0 for ZnPcS. Bovine viral diarrhea virus manifested a moderate sensitivity to ZnPcMe (Δlog=1.8) and a pronounced one to ZnPcS at 5- and 20-min irradiation (Δlog=5.8 and 5.3, respectively). The complexes were unable to inactivate Newcastle disease virus, Coxsackievirus B1 and human adenovirus type 5.

Photodynamic inactivation (PDI) is a light-associated therapeutic approach suitable for treatment of local acute infections. The method is based on specific light-activated compound which by specific irradiation and in the presence of molecular oxygen produced molecular singlet oxygen and other reactive oxygen species, all toxic for pathogenic microbial cells. The study presents photodynamic impact of two recently synthesized water-soluble cationic lutetium (III) acetate phthalocyanines (LuPc-5 and LuPc-6) towards two pathogenic strains, namely, the Gram-negative bacterium Pseudomonas aeruginosa and a fungus Candida albicans. The photodynamic effect was evaluated for the cells in suspensions and organized in 48-h developed biofilms. The relatively high levels of uptakes of LuPc-5 and LuPc-6 were determined for fungal cells compared to bacterial cells. The penetration depths and distribution of both LuPcs into microbial biofilms were investigated by means of confocal fluorescence microscopy. The photoinactivation efficiency was studied for a wide concentration range (0.85–30 μM) of LuPc-5 and LuPc-6 at a light dose of 50 J cm−2 from red light-emitting diode (LED; 665 nm). The PDI study on microbial biofilms showed incomplete photoinactivation (

Background and objectives: Intensive research in the area of photodynamic therapy (PDT) has been made in recent years revealing it as a promising method for the treatment of tumors and inactivation of pathogenic microorganisms. However, for a broader application of this therapy one major challenge, namely a significant improvement of the targeted drug delivery and uptake, still remains. A possible solution of the selectivity problem could be the application of specifically functionalized photosensitizers, in particular phthalocyanine dyes. Materials and methods: Water-soluble Zn(II) phthalocyanines (ZnPcs) with four galactose moieties on non-peripheral and peripheral positions and a non-substituted Zn(II) phthalocyanine were studied for in vitro antitumor activity on three breast cancer cell lines (MCF-7, MDA-MB-231 and HBL-100). The influence of the exposure to ultraviolet (UV) (365 nm) and red (635 nm) light in non-therapeutic doses on the cellular uptake, binding and subcellular localization of three photosensitizers was investigated by confocal laser scanning microscopy. In addition, phototoxicity studies with the tested phthalocyanines on the non-tumorigenic mouse embryo cell line Balb c/3T3 (clone 31) were carried out. Results: The results indicate that the pre-treatment, namely exposure to UV or red light, influences the localization properties of the used dyes. The positions of galactose units to the ZnPc ring also influenced the uptake, localization and the photodynamic response of breast cancer cells. The results show that the galactose substitution, together with exposure to UV or red light in non-therapeutic doses, are important factors for the photodynamic effect. Conclusion: Experimental PDT with galactose-substituted ZnPcs accompanied by UV and red light pre-irradiation leads to a higher photodynamic effect towards breast tumor cells. Thus, the investigated galactopyranosyl-substituted phthalocyanines could be used as a part of the design of intelligent, stimuli-responsive nanosystems for medical applications.

Endogenous fluorescence measurements using UV-VIS excitation wavelengths revealed a variety of natural fluorophores, including the amino acids tyrosine and tryptophan, coenzymes – NADH and flavin, collagen and elastin. Deep minima in the tumor fluorescence signals were observed in the region 540 – 575 nm related to re-absorption of hemoglobin. Such high haemoglobin content was also found as an indication of the tumor’s vascularization and it was clearly pronounced in all dysplastic and tumor sites investigated ex vivo. A photosensitizer from the family of porphyrins was applied as an exogenous fluorescent marker, namely, delta-aminolevulinic acid/protoporphyrin IX (5-ALA/PpIX). The 5-ALA was administered per os six hours before endoscopic observation and spectral measurements at a dose of 20 mg/kg. A high-power light-emitting diode at 405 nm was used as an excitation source (LED-405, 25 mW, CW, Polironik Ltd., Russia). A fiber was introduced through an endoscopic instrumental channel in order to retrieve information about the fluorescence to a USB4000 micro-spectrometer (OceanOptics Inc., Dunedin, USA). The fluorescence detected from in vivo tumor sites has very complex spectral origins. It consists of autofluorescence, fluorescence from exogenous fluorophores and re-absorption from the chromophores accumulated in the investigated tissue. However, the fluorescence of 5-ALA/PpIX was clearly pronounced in the 630 – 710 nm region, having a significant contrast with the surrounding normal mucosa pale fluorescence in the blue-green spectral region. The precancerous mucosa also revealed a red light signal, but with lower intensity levels than the carcinoma lesions observed in situ. False-positive signals were recognized in case of inflammations in the colon and rectum areas, where 5-ALA/PpIX was accumulated as well.