Browsing by Author "Tzoneva R."

Now showing 1 - 7 of 7
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    BIOCOMPATIBILITY AND ANTIFUNGAL ACTIVITY OF SILVER DOPED SiO2/PECTIN COMPOSITE MATERIALS
    (2021-01-01) Angelova T.; Uzunova V.; Rangelova N.; Georgieva N.; Momchilova A.; Tzoneva R.
    The purpose of the study was to evaluate the biocompatibility and antifungal activity of silver doped SiO2/citrus pectin composite materials. The effect of the amount of silver content (0 - 2.5 wt. %) on biocompatibility using L929 fibroblast cells and antifungal activity against Candida albicans 74 was observed. It was established that composites containing 0.5 wt. % and 1 wt. % Ag exhibited biocompatibility as well as revealed low cytotoxicity, good cell adhesion and spreading and luck of apoptosis. The antifungal activity of the composites demonstrated that the size of formed inhibition zones depends on the amount of silver in the materials. Based on the obtained results, silver doped SiO2/ pectin composite materials were proven to be efficient for use as in vivo implants in tissue engineering applications.
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    Cytotoxicity and antibiofilm activity of SiO2/cellulose derivative hybrid materials containing silver nanoparticles
    (2016-01-01) Angelova T.; Rangelova N.; Uzunova V.; Georgieva N.; Andreeva T.; Momchilova A.; Tzoneva R.; Müller R.
    Hybrid materials based on tetraethyl orthosilicate (TEOS), hydroxypropyl cellulose (HPC), or hydroxypropyl methyl cellulose (HPMC) with silver nanoparticles were synthesized. They were analyzed and characterized using differential thermal analysis and thermogravimetry, atomic force microscopy, and static contact angle measurements. It was experimentally demonstrated that the silverdoped hybrid materials have pronounced antibacterial behavior by studying the reduction of Pseudomonas aeruginosa PAO1 biofilm formation on the tested materials. The results revealed biofilm reduction of 35.7% and 30% by SiO2/HPC/2.5% Ag and SiO2/HPMC/2.5% Ag hybrid materials, respectively, compared to the control. Cytotoxicity of examined materials and actin cytoskeleton organization of fibroblasts seeded on the materials was studied as a function of material properties as the type of surface functional groups and silver content. The obtained hybrid materials with low silver content proved efficient in tissue engineering applications since they showed good antibacterial and noncytotoxic properties for eukaryotic cells.
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    CYTOTOXICITY OF COPPER DOPED SiO2-HYDROXYPROPYL CELLULOSE COMPOSITES ON CANCER AND NON-CANCEROUS CELLS
    (2023-01-01) Foteva T.; Vukova T.; Rangelova N.; Georgieva N.; Tzoneva R.
    In the present paper the cytotoxicity of series of sol-gel based copper doped SiO2/HPC composites on lung cancer cell line (A549) and primary human umbilical cord endothelial cells (HUVEC) was investigated. Hydroxypropyl cellulose (HPC), tetraethyl ortosilicate (TEOS) were used for preparation of amorphous matrix in which the copper was added as Cu(NO3)2*3H2O or CuSO4*5H2O in concentration range of 0 - 5 wt. %. We observed that the composite materials at low concentration of Cu (0.5 wt. %) showed no toxic effects on both cell types. The composite material with CuSO4*5H2O was found relatively more toxic, and furthermore, cancer cells are more sensitive to the copper concentration increase to non-cancer cells. The concentration of Cu ions of 2.5 and 5 wt. % were toxic to both cancer and non-cancer cells at 24th hour. At 72th hour of incubation some restoration of cell viability was observed
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    New Indole-3-Propionic Acid and 5-Methoxy-Indole Carboxylic Acid Derived Hydrazone Hybrids as Multifunctional Neuroprotectors
    (2023-04-01) Anastassova N.; Stefanova D.; Hristova-Avakumova N.; Georgieva I.; Kondeva-Burdina M.; Rangelov M.; Todorova N.; Tzoneva R.; Yancheva D.
    In light of the known neuroprotective properties of indole compounds and the promising potential of hydrazone derivatives, two series of aldehyde-heterocyclic hybrids combining those pharmacophores were synthesized as new multifunctional neuroprotectors. The obtained derivatives of indole-3-propionic acid (IPA) and 5-methoxy-indole carboxylic acid (5MICA) had good safety profiles: Hemolytic effects < 5% (200 μM) and IC50 > 150 µM were found in the majority of the SH-SY5Y and bEnd3 cell lines. The 2,3-dihydroxy, 2-hydroxy-4-methoxy, and syringaldehyde derivatives of 5MICA exhibited the strongest neuroprotection against H2O2-induced oxidative stress in SH-SY5Y cells and 6-OHDA-induced neurotoxicity in rat-brain synaptosomes. All the compounds suppressed the iron-induced lipid peroxidation. The hydroxyl derivatives were also the most active in terms of deoxyribose-degradation inhibition, whereas the 3,4-dihydroxy derivatives were able to decrease the superoxide-anion generation. Both series of compounds showed an increased inhibition of hMAO-B, with greater expression detected in the 5MICA hybrids. The in vitro BBB model with the bEnd3 cell line showed that some compounds increased the permeability of the endothelial monolayer while maintaining the tight junctions. The combined results demonstrated that the derivatives of IPA and 5MICA showed strong neuroprotective, antioxidant, MAO-B inhibitory activity and could be considered as prospective multifunctional compounds for the treatment of neurodegenerative disorders.
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    Novel Fluorescent Benzimidazole-Hydrazone-Loaded Micellar Carriers for Controlled Release: Impact on Cell Toxicity, Nuclear and Microtubule Alterations in Breast Cancer Cells
    (2023-06-01) Bryaskova R.; Georgiev N.; Philipova N.; Bakov V.; Anichina K.; Argirova M.; Apostolova S.; Georgieva I.; Tzoneva R.
    Fluorescent micellar carriers with controlled release of a novel anticancer drug were developed to enable intracellular imaging and cancer treatment simultaneously. The nanosized fluorescent micellar systems were embedded with a novel anticancer drug via the self-assembling behavior of well-defined block copolymers based on amphiphilic poly(acrylic acid)-block-poly(n-butyl acrylate) (PAA-b-PnBA) copolymer obtained by Atom Transfer Radical Polymerization (ATRP) and hydrophobic anticancer benzimidazole-hydrazone drug (BzH). Through this method, well-defined nanosized fluorescent micelles were obtained consisting of a hydrophilic PAA shell and a hydrophobic PnBA core embedded with the BzH drug due to the hydrophobic interactions, thus reaching very high encapsulation efficiency. The size, morphology, and fluorescent properties of blank and drug-loaded micelles were investigated using dynamic light scattering (DLS), transmission electron microscopy (TEM), and fluorescent spectroscopy, respectively. Additionally, after 72 h of incubation, drug-loaded micelles released 3.25 μM of BzH, which was spectrophotometrically determined. The BzH drug-loaded micelles were found to exhibit enhanced antiproliferative and cytotoxic effects on MDA-MB-231 cells, with long-lasting effects on microtubule organization, with apoptotic alterations and preferential localization in the perinuclear space of cancer cells. In contrast, the antitumor effect of BzH alone or incorporated in micelles on non-cancerous cells MCF-10A was relatively weak.
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    PREPARATION OF GOLD LOADED MICELLES BASED ON POLY (ETHYLENE GLYCOL) - b - POLY (4-VINYL PYRIDINE) COPOLYMERS AS A TOOL FOR BIOMEDICAL APPLICATIONS
    (2017-01-01) Vircheva S.; Bryaskova R.; Miloshev S.; Tzoneva R.; Dishovsky N.
    Well-defined block copolymers based on poly (ethylene glycol) monomethyl ether and poly (4-vinyl pyridine) (PEG-b-P4VP) were prepared by atom transfer radical polymerization (ATRP). PEG-b-P4VP block copolymer self assembled in an aqueous medium with formation of nanosized spherical micelles was thus prepared. Gold nanoparticles were successfully loaded into PEG-b-P4VP based micelles. This was confirmed by UV-vis, TEM and DLS analysis. The cytotoxicity of gold loaded micelles against MDA-MB-231 breast cancer cells and L929 fibroblasts was determined.
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    SYNTHESIS OF NEW TRIAZOLE AND THIADIAZOLE DERIVATIVES OF THE N,N’-DISUBSTITUTED BENZIMIDAZOLE-2-THIONE AND EVALUATION OF THEIR ANTITUMOR POTENTIAL
    (2022-01-01) Anastassova N.; Georgieva I.; Milanova V.; Tzoneva R.; Radev K.; Yancheva D.; Mavrova A.
    In the present study series of triazole-, thiadiazoleand thiosemicarbazone-benzimidazole hybrid compounds were synthesized as potential anti-cancer agents. In order to determine their antitumor potential and cytotoxic effect (via MTT assay) lung adenocarcinoma (A549) and breast cancer (MDA-MB-231) cell lines were examined. For detection of apoptosis induced by drug treatment, DAPI staining was performed in order to observe the apoptotic alterations in cell nuclei. It was found that the thiadiazole derivative 12 leads to the occurrence of micronuclei, suggesting genotoxic effect. Furthermore, a wound healing assay was performed in order to test whether any changes in cell motility occurred upon treatment with the newly synthesized hybrids, since both cell lines are examples of highly invasive tumours. The cell motility of MDA-MB-231 was impeded mostly by compound 12 (15 % of wound closure) and in A549 compound 9 reduced cell motility by 46 % compared to the control. The obtained results suggest that compound 12 possesses a promising anticancer effect.