Publications by authors named "Ivo Grabchev"

Article Synopsis
  • Researchers synthesized N-modified versions of VV-hemorphin-5 and paired them with different naphthalimides to create colorimetric and antimicrobial properties in cotton fabric.
  • The study found that immobilizing these peptides on fabric affects their flexibility and reduces their antimicrobial effectiveness, which is essential for bacterial contact.
  • Among the tested peptides, the one with a nitro-substituent showed slightly better antibacterial activity, indicating potential for using treated cotton in medical applications like antibacterial dressings.
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A novel second-generation blue fluorescent polyamidoamine dendrimer peripherally modified with sixteen 4--dimethylaninoethyloxy-1,8-naphthalimide units was synthesized. Its basic photophysical characteristics were investigated in organic solvents of different polarity. It was found that in these solvents, the dendrimer is colorless and emitted blue fluorescence with different intensities depending on their polarity.

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Chitosan is a natural biopolymer with a proven ability to impart textile materials with antimicrobial properties when loaded onto them. The mechanism of its bacteriological activity depends on the contact between the positive and negative charges of the amino groups located on the surface of the microbes. Unfortunately, the type of microorganisms and pH influence this action-shortcomings that can be avoided by chitosan modification and by loading its film with substances possessing antimicrobial properties.

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A new water-soluble poly(propylene imine) dendrimer (PPI) modified with 4-sulfo-1,8-naphthalimid units () and its related structure monomer analog () has been prepared by a simple synthesis. The aqueous solution of the monomer exhibited aggregation-induced emission (AIE) at 395 nm, while the dendrimer emitted at 470 nm due to an excimer formation beside the AIE at 395 nm. Fluorescence emission of the aqueous solution of either or was significantly affected by traces of different miscible organic solvents, and the limits of detection were found to be less than 0.

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Recently in the field of chemotherapeutics, to combat the side effects of cisplatin, ruthenium complexes have been investigated extensively. In this work, a bidentate benzimidazole-based ligand, HL [HL = 2-(1-benzo[]imidazol-2-yl)-6-methoxyphenol], was utilized to obtain three Ru(II) arene complexes having a generalized formula [Ru(η--cym)(L)(X)] or [Ru(η--cym)(L)(X)] (where -cym = -cymene). The co-ligand X (X = (i) Cl, (ii) PPh = triphenyl phosphine, and (iii) PTA = 1,3,5-triaza-7-phosphaadamantane) was varied in order to study the effect it has on the antitumor activity of the compounds.

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Article Synopsis
  • This study explores how copper (II) ions form complexes with hemorphin peptide motifs in alkaline water, focusing on the stoichiometry and stability of these complexes.
  • Voltammetric and spectral techniques, including UV-Vis and fluorimetric methods, were used to analyze the complexes, with IR spectroscopy and EPR providing insights into their binding structure and coordination.
  • The potential for these copper complexes to enhance antivirus properties in cotton fibers was also examined, suggesting that the formation of these complexes in situ could improve their effectiveness.
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A novel diamino triazine based 1,8-naphthalimide (NI-DAT) has been designed and synthesized. Its photophysical properties have been investigated in different solvents and its sensory capability evaluated. The fluorescence emission of NI-DAT is significantly impacted by the solvent polarity due to its inherent intramolecular charge transfer character.

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Surface-initiated photopolymerization has been run to synthesize a hydrogel with ZnO particles distributed uniformly along its structure, which has been loaded onto a polyamide fabric. Three samples have been obtained at different concentrations of zinc nitrate (10% (sample PA10); 20% (sample PA20) and 30% (sample PA30) of the weight of the fabric, respectively)) and subjected to gravimetric analysis, scanning electron microscopy and transmission electron microscopy. The effect of the adsorption parameters of the composite material on the removal Drimaren Rot K-7B dye from water has been studied.

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This study addresses the need for antibacterial medication that can overcome the current problems of antibiotics. It does so by suggesting two 1,8-naphthalimides (NI1 and NI2) containing a pyridinium nucleus become attached to the imide-nitrogen atom via a methylene spacer. Those fluorescent derivatives are covalently bonded to the surface of a chloroacetyl-chloride-modified cotton fabric.

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Some new N- and C-modified biomolecular peptide analogues of both VV-hemorphin-5 and VV-hemorphin-7 with varied amino acids (Cys, Glu, His), 1-adamantanecarboxylic acid, and niacin (nicotinic acid) were synthesized by solid-phase peptide synthesis-Fmoc (9-fluorenylmethoxy-carbonyl) chemistry and were characterized in water solutions with different pH using spectroscopic and electrochemical techniques. Basic physicochemical properties related to the elucidation of the peptide structure at physiological pH have been also studied. The results showed that the interaction of peptide compounds with light and electricity preserves the structural and conformational integrity of the compounds in the solutions.

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Ruthenium complexes are being studied extensively as anticancer drugs following the inclusion of NAMI-A and KP1019 in phase II clinical trials for the treatment of metastatic phase and primary tumors. Herein, we designed and synthesized four organometallic Ru(II)-arene complexes [Ru(η--cymene)(L)Cl] (1), [Ru(η-benzene)(L)Cl] (2), [Ru(η--cymene)(L)N] (3) and [Ru(η-benzene)(L)N] (4) [HL = ()-'-(pyren-1-ylmethylene)thiopene-2-carbohydrazide] that have anticancer, antimetastatic and two-photon cell imaging abilities. Moreover, in the transfer hydrogenation of NADH to NAD, these compounds also display good catalytic activity.

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A new methodology for modifying textile materials with dendrimers containing nanoparticles was developed. This involved a combination of eosin Y and -methyldiethanolamine (MDEA) for reducing the copper ions in the dendrimer complex by enabling a photochemical reaction under visible light and ambient conditions. The conversion of copper ions into nanoparticles was monitored using scanning electron microscopy (SEM) and by performing colorimetric, fluorescence, and electron paramagnetic resonance (EPR) studies.

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The activity and interacting ability of a polyamidoamine (PAMAM) dendrimer modified with 4--methylpiperazine-1,8-naphthalimide units (termed D) and complexed by Cu(ii) ions, towards healthy and cancer cells were studied. Comparative electron paramagnetic resonance (EPR) studies of the Cu(ii)-D complex are presented: coordination mode, chemical structure, flexibility and stability of these complexes, in the absence and presence of myeloid cancer cells and peripheral blood mononuclear cells (PBMC). The interactions of Cu(ii) ions in the biological media at different equilibrium times were studied, highlighting different stability and interacting conditions with the cells.

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Here we report on the synthesis and characterization of three new N-modified analogues of hemorphin-4 with rhodamine B. Modified with chloroacetyl, chloride cotton fabric has been dyed and color coordinates of the obtained textile materials were determined. Antiviral and virucidal activities of both the peptide-rhodamine B compounds and the dyed textile material were studied.

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The paper reports on the preparation of composite materials by modifying cotton fabric with a layer of crosslinked glutaraldehyde chitosan containing zinc oxide particles. The ability of chitosan to form complexes with zinc ions has been used to control the size, structure, and distribution of the particles on the fiber surface. The three different obtained materials have been characterized by optical and scanning electron microscopy, Fourier-transform infrared spectroscopy (FTIR), and fluorescent analysis.

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Textile materials, as a suitable matrix for different active substances facilitating their gradual release, can have an important role in skin topical or transdermal therapy. Characterized by compositional and structural variety, those materials readily meet the requirements for applications in specific therapies. Aromatherapy, antimicrobial substances and painkillers, hormone therapy, psoriasis treatment, atopic dermatitis, melanoma, etc.

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(1) Background: (KLAKLAK) is a representative of the antimicrobial peptide group which also shows good anticancer properties. (2) Methods: Herein, we report synthesis using SPPS and characterization by HPLC/MS of a series of shortened analogues of (KLAKLAK). They contain single sequence KLAKLAK as C-terminal amides.

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Two new copper complexes of hyperbranched polymers modified with dansyl units were synthesized and characterized by infrared spectroscopy (IR) and electron paramagnetic resonance (EPR) techniques. It was found that copper ions coordinate predominantly with nitrogen or oxygen atoms of the polymer molecule. The place of the formation of complexes and the number of copper ions involved depend on the chemical structure of the polymer.

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Three new 1,8-naphthalimide derivatives - with different substituents at the C-4 position have been synthesized and characterized. Their photophysical properties have been investigated in organic solvents of different polarity, and their fluorescence intensity was found to depend strongly on both the polarity of the solvents and the type of substituent at C-4. For compounds and having a tertiary amino group linked via an ethylene bridge to the chromophore system, high quantum yield was observed only in non-polar media, whereas for compound , the quantum efficiency did not depend on the medium polarity.

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In this study, a novel 6-(allylamino)-2-(2-(dimethylamino)ethyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (NI3) was synthesized and characterized. Its copolymer with styrene was also obtained. The photophysical characteristics of NI3 were investigated in organic solvents and the results were compared with those of its structural analogue, 2-allyl-6-((2-(dimethylamino)ethyl)amino)-1H-benzo[de]isoquinoline-1,3(2H)-dione (NI4).

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The increasing resistance of many pathogens to most of the common antimicrobials requires the development of new substances with more effective antimicrobial properties. In the present work, we investigated the mechanism of the antimicrobial activity of novel water soluble ammonium quaternary benzanthrone (Compound B) on model membranes, composed of dipalmitoylphosphatidylcholine, 1-palmitoyl-2-oleoylphosphatidylcholine, dipalmitoylphosphatidylglycerol, 1-palmitoyl-2-oleoylphosphatidylglycerol, and dipalmitoylphosphatidylethanolamine (DPPE). The lipids were chosen to represent a model of a bacterial membrane.

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A three-step synthesis was implemented to prepare a quaternary ammonium functionalized blue fluorescent poly(propylene imine) dendrimer modified with pyridinium salt of 4-acylamino-1,8-naphthalimide. The new cationic dendrimer absorbs in the ultraviolet light region and emits blue fluorescence. Its spectral characteristics in organic solvents and in an aqueous solution were studied.

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To prepare a novel highly photo-stable fluorescent chemosensor, curcumin was successfully immobilized to polyamidoamine dendrimer of zero (S1), first (S2) and second (S3) generations conjugated-UV absorber moieties. Chemical structure of synthesized chemosensors were well-analysed by FTIR, H-NMR, CNMR, elemental analysis, DSC and UV-vis techniques. Photo-physical characteristics and solvatochromism effect of three novel chemosensors in organic solvents with different dielectric constants ranged 2.

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A new fluorescent Zn(II) complex of symmetrical tripod form based on a 3-substituted benzanthrone (BT) has been synthesized and characterised. The basic photophysical properties of the new metal complex have been determined. It has been found by fluorescence spectroscopy that, one zinc ion forms a complex with the tripod ligand.

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A second-generation poly(propylene imine) dendrimer modified with acridine and its Cu(II) complex have been synthesized for the first time. It has been found that two copper ions form complexes with the nitrogen atoms of the dendrimeric core by coordinate bonds. The new compounds have been characterized by nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), fourier-transform infrared spectroscopy (FTIR) and fluorescence spectroscopy.

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