Elena Gardeva - Academia.edu (original) (raw)

Papers by Elena Gardeva

Comptes rendus de l'Académie bulgare des sciences: sciences mathématiques et naturelles

In this paper theoretical and experimental results on the heating process of gold nanoparticles i... more In this paper theoretical and experimental results on the heating process of gold nanoparticles irradiated by nanosecond laser pulses are presented. Gold nanoparticles with diameters of 40 and 100 nm in water are considered in the presented study. Based on the Mie scattering theory the optimal conditions of particle absorption for different wavelengths in the visible spectra are estimated. The calculated absorption cross-sections are implemented in 2D heat diffusion equation which describes the particle and the surrounding medium heating process. Using this model the dependence of the achieved maximal particles temperature on the applied laser uence is obtained. The results indicate that even at laser uences lower by order of magnitude than the typical threshold for tissue modification, the gold nanoparticles are heated to temperatures higher than the critical for water. Such temperatures are suffcient to induce permanent modification in a biological object in a close vicinity of th...

Local application of heat is a well-known concept in therapeutic medicine that has been explored ... more Local application of heat is a well-known concept in therapeutic medicine that has been explored extensively for the treatment of cancer and other conditions. The plasmon resonance for gold nanoparticles (GNPs) is at �520 nm. The aim of the present investigation was to elucidate the effect of different size GNPs combined with laser irradiation on permanent human cancer cell line HeLa. The samples were irradiated at k=532 nm, pulse duration s p= 15 ns and repetition rate 1 Hz. Laser pulses with energy densities of F= 80mJ/cm2 and F=25mJ/cm2 were used. The irradiation of the samples was performed using 2, 3 and 10 laser pulses. The potential anti-tumor effect in vitro of GNPs and laser treatment on HeLa cells were studied by MTT assay. Cells treated with GNPs or laser irradiation alone showed no significant difference from the control The combination of GNPs and laser treatment showed cytotoxic effect when cells were incubated with GNPs (100 nm), irradiated with 3 pulses and F= 80mJ/c...

ABSTRACT Export Date: 18 October 2014

The in vitro effect of highly purified B-phycoerythrin from Porphyridium cruentum on the prolifer... more The in vitro effect of highly purified B-phycoerythrin from Porphyridium cruentum on the proliferation of Graffi myeloid tumor cells was studied. The MTT assay showed a dosedependentinhibition of tumor cell proliferation. About 50 and 63% cell growth suppression was recorded using 50 and 100 μg/ml B-phycoerythrin, respectively. In contrast, the pigment stimulated the proliferative response of normal hamster bone marrow cells (113 ± 4.34 and 154 ± 8.6% for 50 and 100 μg/ml, respectively). Fluorescence microscopy ofacridine orange and propidium iodide - double stained tumor cells revealed characteristic apoptotic features like nuclear shrinkage, condensed chromatin and membrane blebbing, as well as formation of apoptotic bodies and DNA fragmentation in B-phycoerythrin-treated cells. A concomitant dose-dependent increase in the activities of glutathione reductase and especially of superoxide dismutase (both Mn SOD and Cu/Zn SOD) in Graffi cells in response to the treatment was observed...

Revue de médecine vétérinaire

Polyclonal antibodies against Caprine Herpes virus 1 (CpHV-1) were prepared and used for developm... more Polyclonal antibodies against Caprine Herpes virus 1 (CpHV-1) were prepared and used for development of a direct immunofluorescence test for detection of CpHV-1 infection. The test was evaluated using infected and non infected MDBK cells. Specific asymmetric perinuclear immunofluorescence was observed since 2 hours post infection and lasted up to the end point investigated in monolayers obtained at the 36th hour post infection. Infected and uninfected MDBK cells were analyzed in parallel following May-Grünwald Giemsa and double fluorochrome staining with acridine orange (AO) and propidium iodide (PI). The dynamics of the cytopathological changes showed cell shrinkage, cell loss and marked increase in the apoptotic index after the 12th hour post infection. Infected cells were rearranged into many syncytia in which live and apoptotic cells could be present at the 24th up to the 36th hour post infection. The present investigation clearly indicated that immunofluorescence test is an app...

Journal of Applied Phycology

Gloeocapsa sp. strain R-06/1 was grown at three different temperatures and two light intensities.... more Gloeocapsa sp. strain R-06/1 was grown at three different temperatures and two light intensities. The fatty acid composition of this blue-green alga was determined for the first time. The relative content of almost all fatty acids was changed depending on the temperature of cultivation. Biological activity of the tested fatty acids and ethanol extracts isolated from Gloeocapsa sp. were also influenced by the culture conditions of the alga. For antibacterial and antifungal assay seven pathogens (Streptococcus pyogenes, Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium and Candida albicans) were used. The cytotoxicity was tested on a human cervix epitheloid carcinoma cell line, HeLa. Fatty acids inhibited the growth of Gram-positive bacterium S. pyogenes and exhibited a cytotoxic effect on HeLa cells with IC50 values in the range of 23.2–18.1 μg.ml-1. Ethanol extracts from biomass, obtained at all culture conditions decreased the ...

Although a large number of strains have been shown to possess anticancer activity, the microalgal... more Although a large number of strains have been shown to possess anticancer activity, the microalgal and cyanobacterial potential is still largely unexplored. The present study was aimed to evaluate and compare the growth inhibitory activity of 33 extracts, 15 fatty acid mixtures and five exopolysaccharides from 19 species on HeLa cells, using MTT assay. All investigated strains showed growth inhibitory activity of at least one tested extract/constituent. More than 80% decrease in Hela cells viability was registered for the crude hot water extract of Gloeocapsa sp. and ethanol extracts of the new Bulgarian isolates Gloeocapsa sp. and Chlorella sp. Most active cell-free culture liquids were these of Anabaena sp. and Synechocystis sp., while the exopolysaccharides of Gloeocapsa sp. exhibited the lowest IC50 value (24.4 μg/ml). An interesting and useful finding of our investigation was that the isolated fatty acid mixtures from five out of eight cyanobacterial strains and from four out of...

Comptes rendus de l'Académie bulgare des sciences: sciences mathématiques et naturelles

Biophotonics: Photonic Solutions for Better Health Care III, 2012

ABSTRACT In this work an application of gold nanoparticles in in-vitro photothermal cancer cell t... more ABSTRACT In this work an application of gold nanoparticles in in-vitro photothermal cancer cell therapy is demonstrated. Gold nanoparticles with different diameters - 40, 100 and 200 nm are mixed with HeLa cancer cells. After incubation, the nanoparticles are found to be deposited on the cell's membrane or enter into the cells. Pulsed laser radiation at wavelength of 532 nm delivered by Nd:YAG system is used to irradiate the samples. The experiments are performed at fluences in the range from 50 mJ/cm2 up to the established safety standard for medical lasers of 100 mJ/cm2. The cell viability as a function of the particle dimensions and laser fluence is estimated. The nanoparticles heating and cooling dynamics is traced by a numerical model based on heat diffusion equation combined with Mie theory for calculation of the optical properties of nanoparticles. The particle response to the nanosecond laser heating is investigated experimentally as gold colloids are irradiated at different fluences. The threshold fluences for particle's melting and boiling are defined. We show that at the presented fluence range the particles are decomposed into smaller fragments and even short irradiation time leads to decrease of cell viability.

Biotechnology & Biotechnological Equipment, 2009

ABSTRACT The cell wall sulfated polysaccharide of the red microalga Porphyridium cruentum (Rhodop... more ABSTRACT The cell wall sulfated polysaccharide of the red microalga Porphyridium cruentum (Rhodophyta) (PcrPSH) exhibited strong antitumor activity against Graffi myeloid tumor in hamsters both in vitro and in vivo. When tested in vivo, depending on the concentration and the way of application, this polysaccharide decreased transplantability in all experimental groups till 20 days of observation and mortality rate. The tumor growth was retarded and the mean survival time was prolonged with 10 - 16 days. Applied in in vitro experiments the PcrPSH increased both—spreading and phagocytic ability of peritoneal macrophages from healthy and Graffi tumor bearing hamsters in a dose—dependent manner. Primary Graffi tumor cell culture, cultivated in the presence of PcrPSH showed significant decrease of cell viability, determined by MTT test, while in cells derived from bone marrow it was increased at the same conditions of cultivation and concentration of polysaccharide. Primary Graffi tumor cell culture, treated with PcrPSH showed the appearance of a characteristic DNA ladder on agarose gel electrophoresis, which is a biochemical hallmark of apoptosis. The manifested anticancer activity of PcrPSH could be associated with its immunostimulating action as well as with direct cytotoxic properties. Based on these results, we could suggest that the tested algal PcrPSH is a promising candidate as an antitumor agent. Further studies will be done to clarify the mechanisms of a biological action of PcrPSH.

Nanophotonics IV, 2012

ABSTRACT In this study, we synthesized different types of ZnO samples (thin and nanostructured fi... more ABSTRACT In this study, we synthesized different types of ZnO samples (thin and nanostructured films) and investigated their potential application in biomedicine. The properties of ZnO films are strongly dependent on the synthesis process and the experimental conditions. Thus, the samples were prepared by pulsed laser deposition (PLD), which allows excellent control over the stoichiometry and surface morphology. Cell suspensions of the same concentration and volume (i.e. same number of cells) were seeded on each sample. The subjects of interest were 3T3 fibroblast, MCF-7 and HeLa cancer cells. The influence of the ZnO surface morphology on the viability of these three different cell cultures was studied. The cell type defines the appropriate surface morphology for cell culturing. The nanoscale morphology of the samples supports the HeLa cell viability, while only a small quantity of MCF-7 cells are able to adhere, spread and survive on them.

Brazilian Archives of Biology and Technology, 2014

Pure C-phycocyanin (C-PC) was isolated from Arthronema africanum to evaluate its potential antitu... more Pure C-phycocyanin (C-PC) was isolated from Arthronema africanum to evaluate its potential antitumor effects in vivo and in vitro. Experimental myeloid Graffi tumor in hamsters was used as a model. The cell proliferation assay showed that C-PC treatment, at concentration of 100 µg mL-1 for 24 h, significantly inhibited the growth of Graffi tumor cells (51.4% viability). Agarose gel electrophoresis of the genomic DNA of treated cells displayed time-and concentration-dependent fragmentation pattern, typical for apoptosis. Apoptotic process was related to the increase in cellular manganese and copper/zinc superoxide dismutases and glutathione reductase activities, coupled with a low catalase activity. In vivo C-PC administration (5.0 mg kg-1 body weight) suppressed the tumor transplantability and growth, while the mean survival time of the tumor-bearing hamsters was increased. The results revealed promising antitumor activities of A. africanum C-PC and suggested the potential of this natural biliprotein pigment for future pharmacological and medical applications. The study provided new data on the mechanism of the C-PCinduced apoptosis in which the imbalance of antioxidant enzymes that favoured hydrogen peroxide accumulation might play a leading role.

Biotechnology & Biotechnological Equipment, 2012

ABSTRACT The efforts of scientists are aimed at finding anti-cancer agents of natural origin whic... more ABSTRACT The efforts of scientists are aimed at finding anti-cancer agents of natural origin which have high biological activity, low toxicity and broad spectrum of therapeutic activity. This study was designed to determine the cytotoxic properties of polysaccharides derived from the red microalgae Dixoniella grisea and Porphyridium cruentum and to elucidate the mechanism of their action on two permanent human cell lines MCF-7 (breast adenocarcinoma) and HeLa (cervical carcinoma), as well as on primary culture from Graffi myeloid tumor in hamsters. Our investigations indicated that both algal polysaccharides showed high cytotoxic and apoptogenic activities on cancer cells and may be a promising alternative to synthetic substances.

Applied Surface Science, 2011

Theoretical and experimental results on the heating process of gold nanoparticles irradiated by n... more Theoretical and experimental results on the heating process of gold nanoparticles irradiated by nanosecond laser pulses are presented. The efficiency of particle heating is demonstrated by in-vitro photothermal therapy of human tumor cells. Gold nanoparticles with diameters of 40 and 100 nm are added as colloid in the cell culture and the samples are irradiated by nanosecond pulses at wavelength of 532 nm delivered by Nd:YAG laser system. The results indicate clear cytotoxic effect of application of nanoparticle as more efficient is the case of using particles with diameter of 100 nm. The theoretical analysis of the heating process of nanoparticle interacting with laser radiation is based on the Mie scattering theory, which is used for calculation of the particle absorption coefficient, and two-dimensional heat diffusion model, which describes the particle and the surrounding medium temperature evolution. Using this model the dependence of the achieved maximal temperature in the particles on the applied laser fluence and time evolution of the particle temperature is obtained.

Journal of Developmental Biology and Tissue Engineering, 2011

The main goal is connected with providing, on the one hand, of active tumor-suppressor genes for ... more The main goal is connected with providing, on the one hand, of active tumor-suppressor genes for prevention of eventual malignant transformations, and, on the other hand, of functionally active oncogenes for prevention of early aging and death, both in vitro and in vivo. Modulation of an adequate immune control was also necessary, and in this way any eventual unwished side effects from the genetic manipulations applied, could be escaped. Gene transfer in laboratory-cultivated mouse embryonic stem cells (mESCs) was made by use of appropriate recombinant DNA-constructs, which contained the promoter for gene, coding Elongation Factor 1-alpha (EF1-α), isolated from adenoassociated virus (AAV) (Parvoviridae); gene Dcn1, isolated from 3T3 fibroblasts of laboratory mice Balb/c, as well as gene for neomycin resistance, isolated from bacterial DNA-plasmid. Besides those indicated in the scientific literature inactivation of oncogene Dcn1 in the process of normal cell differentiation, its presence in the genome was supported and confirmed by our results from electrophorhesis of genomic DNA from normal mature epithelial cells of adult Balb/c laboratory mice. Furthermore, electrophorhetic profiles of genetic material from wild type (WT) on oncogene Dcn1 and "knock-down" (KD) on it inbred lines experimental mice differed not only on this oncogene, but also on the tumor-suppressor gene HACE1 in both categories of laboratory rodents. Similarly transfected Hela and RIN-5F malignant cells were then in vitro-co-cultivated with myeloid cell precursors, derived from populations of non-transfected laboratory-cultivated mESCs, in the presence of Doxyciclin, known from many literature data as activator of tumor-suppressor genes from STAT-family expression. Our results were also confirmed by the noticed differences in the degree of myeloid differentiation of derived precursor cells in their in vitro-co-cultivation with containing additional copies of tumor-suppressor genes malignant cells from both lines described, in comparison with the data, obtained in their laboratory co-cultivation with non-treated human cervical carcinoma Hela cells. Differences were also observed in in vitro-co-cultivation with the derived by us normal mESCs, containing additional copy of oncogene Dcn1 by the described above transfection with recombinant DNA-constructs. On the other hand, the derived normal cells with inserted additional copy of oncogene Dcn1 have indicated good safety and immunogenity. These cells have also indicated preserved normal cell characteristics, as well as eventual over-expression of the experimentally-activated oncogene Dcn1 in them.

Journal of Clinical Immunology and Immunopathology Research, 2012

Studies on the biology of immune cells are mainly focused on their role as immune activators and ... more Studies on the biology of immune cells are mainly focused on their role as immune activators and modulators. In their appropriate cultivation and/or modifications, they have shown abilities for an enhanced expression of specific effective molecules. These ...

International journal of pharmaceutics, Jan 15, 2010

Nanofibrous implants containing quaternized chitosan (QCh), poly(L-lactide-co-D,L-lactide) (coPLA... more Nanofibrous implants containing quaternized chitosan (QCh), poly(L-lactide-co-D,L-lactide) (coPLA), and the antitumor drug doxorubicin (DOX) were fabricated by electrospinning. The surface chemical composition and the morphology of the implants were characterized by XPS and SEM. In vitro cell viability studies demonstrated that QCh- and DOX-based implants exhibited high cytotoxicity against Graffi tumor cells. The implants efficiently inhibited the growth of Graffi tumor in hamsters with minimum weight loss. Insertion of QCh/coPLA/DOX implants in the place of removed tumor led to an increase in the animal survival rate and to a decrease in the percentage of recurrences.

Comptes rendus de l'Académie bulgare des sciences: sciences mathématiques et naturelles

In this paper theoretical and experimental results on the heating process of gold nanoparticles i... more In this paper theoretical and experimental results on the heating process of gold nanoparticles irradiated by nanosecond laser pulses are presented. Gold nanoparticles with diameters of 40 and 100 nm in water are considered in the presented study. Based on the Mie scattering theory the optimal conditions of particle absorption for different wavelengths in the visible spectra are estimated. The calculated absorption cross-sections are implemented in 2D heat diffusion equation which describes the particle and the surrounding medium heating process. Using this model the dependence of the achieved maximal particles temperature on the applied laser uence is obtained. The results indicate that even at laser uences lower by order of magnitude than the typical threshold for tissue modification, the gold nanoparticles are heated to temperatures higher than the critical for water. Such temperatures are suffcient to induce permanent modification in a biological object in a close vicinity of th...

Local application of heat is a well-known concept in therapeutic medicine that has been explored ... more Local application of heat is a well-known concept in therapeutic medicine that has been explored extensively for the treatment of cancer and other conditions. The plasmon resonance for gold nanoparticles (GNPs) is at �520 nm. The aim of the present investigation was to elucidate the effect of different size GNPs combined with laser irradiation on permanent human cancer cell line HeLa. The samples were irradiated at k=532 nm, pulse duration s p= 15 ns and repetition rate 1 Hz. Laser pulses with energy densities of F= 80mJ/cm2 and F=25mJ/cm2 were used. The irradiation of the samples was performed using 2, 3 and 10 laser pulses. The potential anti-tumor effect in vitro of GNPs and laser treatment on HeLa cells were studied by MTT assay. Cells treated with GNPs or laser irradiation alone showed no significant difference from the control The combination of GNPs and laser treatment showed cytotoxic effect when cells were incubated with GNPs (100 nm), irradiated with 3 pulses and F= 80mJ/c...

ABSTRACT Export Date: 18 October 2014

The in vitro effect of highly purified B-phycoerythrin from Porphyridium cruentum on the prolifer... more The in vitro effect of highly purified B-phycoerythrin from Porphyridium cruentum on the proliferation of Graffi myeloid tumor cells was studied. The MTT assay showed a dosedependentinhibition of tumor cell proliferation. About 50 and 63% cell growth suppression was recorded using 50 and 100 μg/ml B-phycoerythrin, respectively. In contrast, the pigment stimulated the proliferative response of normal hamster bone marrow cells (113 ± 4.34 and 154 ± 8.6% for 50 and 100 μg/ml, respectively). Fluorescence microscopy ofacridine orange and propidium iodide - double stained tumor cells revealed characteristic apoptotic features like nuclear shrinkage, condensed chromatin and membrane blebbing, as well as formation of apoptotic bodies and DNA fragmentation in B-phycoerythrin-treated cells. A concomitant dose-dependent increase in the activities of glutathione reductase and especially of superoxide dismutase (both Mn SOD and Cu/Zn SOD) in Graffi cells in response to the treatment was observed...

Revue de médecine vétérinaire

Polyclonal antibodies against Caprine Herpes virus 1 (CpHV-1) were prepared and used for developm... more Polyclonal antibodies against Caprine Herpes virus 1 (CpHV-1) were prepared and used for development of a direct immunofluorescence test for detection of CpHV-1 infection. The test was evaluated using infected and non infected MDBK cells. Specific asymmetric perinuclear immunofluorescence was observed since 2 hours post infection and lasted up to the end point investigated in monolayers obtained at the 36th hour post infection. Infected and uninfected MDBK cells were analyzed in parallel following May-Grünwald Giemsa and double fluorochrome staining with acridine orange (AO) and propidium iodide (PI). The dynamics of the cytopathological changes showed cell shrinkage, cell loss and marked increase in the apoptotic index after the 12th hour post infection. Infected cells were rearranged into many syncytia in which live and apoptotic cells could be present at the 24th up to the 36th hour post infection. The present investigation clearly indicated that immunofluorescence test is an app...

Journal of Applied Phycology

Gloeocapsa sp. strain R-06/1 was grown at three different temperatures and two light intensities.... more Gloeocapsa sp. strain R-06/1 was grown at three different temperatures and two light intensities. The fatty acid composition of this blue-green alga was determined for the first time. The relative content of almost all fatty acids was changed depending on the temperature of cultivation. Biological activity of the tested fatty acids and ethanol extracts isolated from Gloeocapsa sp. were also influenced by the culture conditions of the alga. For antibacterial and antifungal assay seven pathogens (Streptococcus pyogenes, Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium and Candida albicans) were used. The cytotoxicity was tested on a human cervix epitheloid carcinoma cell line, HeLa. Fatty acids inhibited the growth of Gram-positive bacterium S. pyogenes and exhibited a cytotoxic effect on HeLa cells with IC50 values in the range of 23.2–18.1 μg.ml-1. Ethanol extracts from biomass, obtained at all culture conditions decreased the ...

Although a large number of strains have been shown to possess anticancer activity, the microalgal... more Although a large number of strains have been shown to possess anticancer activity, the microalgal and cyanobacterial potential is still largely unexplored. The present study was aimed to evaluate and compare the growth inhibitory activity of 33 extracts, 15 fatty acid mixtures and five exopolysaccharides from 19 species on HeLa cells, using MTT assay. All investigated strains showed growth inhibitory activity of at least one tested extract/constituent. More than 80% decrease in Hela cells viability was registered for the crude hot water extract of Gloeocapsa sp. and ethanol extracts of the new Bulgarian isolates Gloeocapsa sp. and Chlorella sp. Most active cell-free culture liquids were these of Anabaena sp. and Synechocystis sp., while the exopolysaccharides of Gloeocapsa sp. exhibited the lowest IC50 value (24.4 μg/ml). An interesting and useful finding of our investigation was that the isolated fatty acid mixtures from five out of eight cyanobacterial strains and from four out of...

Comptes rendus de l'Académie bulgare des sciences: sciences mathématiques et naturelles

Biophotonics: Photonic Solutions for Better Health Care III, 2012

ABSTRACT In this work an application of gold nanoparticles in in-vitro photothermal cancer cell t... more ABSTRACT In this work an application of gold nanoparticles in in-vitro photothermal cancer cell therapy is demonstrated. Gold nanoparticles with different diameters - 40, 100 and 200 nm are mixed with HeLa cancer cells. After incubation, the nanoparticles are found to be deposited on the cell's membrane or enter into the cells. Pulsed laser radiation at wavelength of 532 nm delivered by Nd:YAG system is used to irradiate the samples. The experiments are performed at fluences in the range from 50 mJ/cm2 up to the established safety standard for medical lasers of 100 mJ/cm2. The cell viability as a function of the particle dimensions and laser fluence is estimated. The nanoparticles heating and cooling dynamics is traced by a numerical model based on heat diffusion equation combined with Mie theory for calculation of the optical properties of nanoparticles. The particle response to the nanosecond laser heating is investigated experimentally as gold colloids are irradiated at different fluences. The threshold fluences for particle's melting and boiling are defined. We show that at the presented fluence range the particles are decomposed into smaller fragments and even short irradiation time leads to decrease of cell viability.

Biotechnology & Biotechnological Equipment, 2009

ABSTRACT The cell wall sulfated polysaccharide of the red microalga Porphyridium cruentum (Rhodop... more ABSTRACT The cell wall sulfated polysaccharide of the red microalga Porphyridium cruentum (Rhodophyta) (PcrPSH) exhibited strong antitumor activity against Graffi myeloid tumor in hamsters both in vitro and in vivo. When tested in vivo, depending on the concentration and the way of application, this polysaccharide decreased transplantability in all experimental groups till 20 days of observation and mortality rate. The tumor growth was retarded and the mean survival time was prolonged with 10 - 16 days. Applied in in vitro experiments the PcrPSH increased both—spreading and phagocytic ability of peritoneal macrophages from healthy and Graffi tumor bearing hamsters in a dose—dependent manner. Primary Graffi tumor cell culture, cultivated in the presence of PcrPSH showed significant decrease of cell viability, determined by MTT test, while in cells derived from bone marrow it was increased at the same conditions of cultivation and concentration of polysaccharide. Primary Graffi tumor cell culture, treated with PcrPSH showed the appearance of a characteristic DNA ladder on agarose gel electrophoresis, which is a biochemical hallmark of apoptosis. The manifested anticancer activity of PcrPSH could be associated with its immunostimulating action as well as with direct cytotoxic properties. Based on these results, we could suggest that the tested algal PcrPSH is a promising candidate as an antitumor agent. Further studies will be done to clarify the mechanisms of a biological action of PcrPSH.

Nanophotonics IV, 2012

ABSTRACT In this study, we synthesized different types of ZnO samples (thin and nanostructured fi... more ABSTRACT In this study, we synthesized different types of ZnO samples (thin and nanostructured films) and investigated their potential application in biomedicine. The properties of ZnO films are strongly dependent on the synthesis process and the experimental conditions. Thus, the samples were prepared by pulsed laser deposition (PLD), which allows excellent control over the stoichiometry and surface morphology. Cell suspensions of the same concentration and volume (i.e. same number of cells) were seeded on each sample. The subjects of interest were 3T3 fibroblast, MCF-7 and HeLa cancer cells. The influence of the ZnO surface morphology on the viability of these three different cell cultures was studied. The cell type defines the appropriate surface morphology for cell culturing. The nanoscale morphology of the samples supports the HeLa cell viability, while only a small quantity of MCF-7 cells are able to adhere, spread and survive on them.

Brazilian Archives of Biology and Technology, 2014

Pure C-phycocyanin (C-PC) was isolated from Arthronema africanum to evaluate its potential antitu... more Pure C-phycocyanin (C-PC) was isolated from Arthronema africanum to evaluate its potential antitumor effects in vivo and in vitro. Experimental myeloid Graffi tumor in hamsters was used as a model. The cell proliferation assay showed that C-PC treatment, at concentration of 100 µg mL-1 for 24 h, significantly inhibited the growth of Graffi tumor cells (51.4% viability). Agarose gel electrophoresis of the genomic DNA of treated cells displayed time-and concentration-dependent fragmentation pattern, typical for apoptosis. Apoptotic process was related to the increase in cellular manganese and copper/zinc superoxide dismutases and glutathione reductase activities, coupled with a low catalase activity. In vivo C-PC administration (5.0 mg kg-1 body weight) suppressed the tumor transplantability and growth, while the mean survival time of the tumor-bearing hamsters was increased. The results revealed promising antitumor activities of A. africanum C-PC and suggested the potential of this natural biliprotein pigment for future pharmacological and medical applications. The study provided new data on the mechanism of the C-PCinduced apoptosis in which the imbalance of antioxidant enzymes that favoured hydrogen peroxide accumulation might play a leading role.

Biotechnology & Biotechnological Equipment, 2012

ABSTRACT The efforts of scientists are aimed at finding anti-cancer agents of natural origin whic... more ABSTRACT The efforts of scientists are aimed at finding anti-cancer agents of natural origin which have high biological activity, low toxicity and broad spectrum of therapeutic activity. This study was designed to determine the cytotoxic properties of polysaccharides derived from the red microalgae Dixoniella grisea and Porphyridium cruentum and to elucidate the mechanism of their action on two permanent human cell lines MCF-7 (breast adenocarcinoma) and HeLa (cervical carcinoma), as well as on primary culture from Graffi myeloid tumor in hamsters. Our investigations indicated that both algal polysaccharides showed high cytotoxic and apoptogenic activities on cancer cells and may be a promising alternative to synthetic substances.

Applied Surface Science, 2011

Theoretical and experimental results on the heating process of gold nanoparticles irradiated by n... more Theoretical and experimental results on the heating process of gold nanoparticles irradiated by nanosecond laser pulses are presented. The efficiency of particle heating is demonstrated by in-vitro photothermal therapy of human tumor cells. Gold nanoparticles with diameters of 40 and 100 nm are added as colloid in the cell culture and the samples are irradiated by nanosecond pulses at wavelength of 532 nm delivered by Nd:YAG laser system. The results indicate clear cytotoxic effect of application of nanoparticle as more efficient is the case of using particles with diameter of 100 nm. The theoretical analysis of the heating process of nanoparticle interacting with laser radiation is based on the Mie scattering theory, which is used for calculation of the particle absorption coefficient, and two-dimensional heat diffusion model, which describes the particle and the surrounding medium temperature evolution. Using this model the dependence of the achieved maximal temperature in the particles on the applied laser fluence and time evolution of the particle temperature is obtained.

Journal of Developmental Biology and Tissue Engineering, 2011

The main goal is connected with providing, on the one hand, of active tumor-suppressor genes for ... more The main goal is connected with providing, on the one hand, of active tumor-suppressor genes for prevention of eventual malignant transformations, and, on the other hand, of functionally active oncogenes for prevention of early aging and death, both in vitro and in vivo. Modulation of an adequate immune control was also necessary, and in this way any eventual unwished side effects from the genetic manipulations applied, could be escaped. Gene transfer in laboratory-cultivated mouse embryonic stem cells (mESCs) was made by use of appropriate recombinant DNA-constructs, which contained the promoter for gene, coding Elongation Factor 1-alpha (EF1-α), isolated from adenoassociated virus (AAV) (Parvoviridae); gene Dcn1, isolated from 3T3 fibroblasts of laboratory mice Balb/c, as well as gene for neomycin resistance, isolated from bacterial DNA-plasmid. Besides those indicated in the scientific literature inactivation of oncogene Dcn1 in the process of normal cell differentiation, its presence in the genome was supported and confirmed by our results from electrophorhesis of genomic DNA from normal mature epithelial cells of adult Balb/c laboratory mice. Furthermore, electrophorhetic profiles of genetic material from wild type (WT) on oncogene Dcn1 and "knock-down" (KD) on it inbred lines experimental mice differed not only on this oncogene, but also on the tumor-suppressor gene HACE1 in both categories of laboratory rodents. Similarly transfected Hela and RIN-5F malignant cells were then in vitro-co-cultivated with myeloid cell precursors, derived from populations of non-transfected laboratory-cultivated mESCs, in the presence of Doxyciclin, known from many literature data as activator of tumor-suppressor genes from STAT-family expression. Our results were also confirmed by the noticed differences in the degree of myeloid differentiation of derived precursor cells in their in vitro-co-cultivation with containing additional copies of tumor-suppressor genes malignant cells from both lines described, in comparison with the data, obtained in their laboratory co-cultivation with non-treated human cervical carcinoma Hela cells. Differences were also observed in in vitro-co-cultivation with the derived by us normal mESCs, containing additional copy of oncogene Dcn1 by the described above transfection with recombinant DNA-constructs. On the other hand, the derived normal cells with inserted additional copy of oncogene Dcn1 have indicated good safety and immunogenity. These cells have also indicated preserved normal cell characteristics, as well as eventual over-expression of the experimentally-activated oncogene Dcn1 in them.

Journal of Clinical Immunology and Immunopathology Research, 2012

Studies on the biology of immune cells are mainly focused on their role as immune activators and ... more Studies on the biology of immune cells are mainly focused on their role as immune activators and modulators. In their appropriate cultivation and/or modifications, they have shown abilities for an enhanced expression of specific effective molecules. These ...

International journal of pharmaceutics, Jan 15, 2010

Nanofibrous implants containing quaternized chitosan (QCh), poly(L-lactide-co-D,L-lactide) (coPLA... more Nanofibrous implants containing quaternized chitosan (QCh), poly(L-lactide-co-D,L-lactide) (coPLA), and the antitumor drug doxorubicin (DOX) were fabricated by electrospinning. The surface chemical composition and the morphology of the implants were characterized by XPS and SEM. In vitro cell viability studies demonstrated that QCh- and DOX-based implants exhibited high cytotoxicity against Graffi tumor cells. The implants efficiently inhibited the growth of Graffi tumor in hamsters with minimum weight loss. Insertion of QCh/coPLA/DOX implants in the place of removed tumor led to an increase in the animal survival rate and to a decrease in the percentage of recurrences.