Ivo Grabchev

Surface enhanced Raman spectroscopy as a new spectral technique for quantitative detection of metal ions

Four newly synthesized poly (propylene amine) dendrimers from first and second generation modified with 1,8-naphthalimide units in the dendrimer periphery have been investigated as ligands for the detection of heavy metal ions (Al(3+), Sb(2+), As(2+), Cd(2+) and Pb(2+)) by surface-enhanced Raman spectroscopy. Calibration curves were established for all metal ions between the concentration ranges of 1 x 10(-6) to 5 x 10(-4) M. It has been shown that these dendrimers can be coordinated, especially with different metal ions. Using dendrimer molecules and silver colloids at the same time allowed us to obtain an SERS signal from the abovementioned metal ions at very low concentrations. Principle component analysis (PCA) analysis was also applied to the collected SERS data. Four different PCA models were developed to accomplish the discrimination of five metal ions, which interacted with each of the four dendrimer molecules, separately. A detailed investigation was performed in the present study to provide the basis of a new approach for heavy metal detection.

Synthesis, photophysical and antimicrobial activity of new water soluble ammonium quaternary benzanthrone in solution and in polylactide film

The synthesis of a new cationic water soluble fluorescent 1-[(7-oxo-7H-benzo[de]anthracen-3-ylcarbamoyl)-methyl]-triethylammonium chloride (B) has been described. Due to the presence of the quaternary amino group, the compound is soluble in water. Its photophysical characteristics in aqueous solution and organic solvents with different polarity have been determined using absorption and fluorescence spectroscopy. The photostability of compound B has been investigated in aqueous media. The newly synthesized compound has been tested in vitro for its antimicrobial activity against eight bacterial and two yeasts cultures. The results obtained suggest that the newly synthesized compound is effective in treating the relevant pathogens and is suitable in designing new effective antimicrobial preparations. The incorporation of the compound into thin polylactic acid film and its release into water solution has been also investigated. It was demonstrated that the compound released from the polymer polylactic acid matrix exhibited a prolonged good antibacterial activity.

Fluorescent Hydrogel–Textile Composite Material Synthesized by Photopolymerization

A fluorescent textile sensor and its capacities to detect pH changes in aqueous solutions have been reported. A new hydrogel-cotton fabric was obtained via surface initiated photopolymerization of 2-aminoethylmethacrylate hydrochloride, with N,N′-methylene-bis-acrylamide as a crosslinker, and fluorophore and modified eosin Y and N-methyldiethanolamine as photoinitiators. The synthesis of the modified eosin Y and a new 1,8-naphtalimide used as signal units in the hydrogel composite have been described. It has been found that the concentration of the photoinitiator affects the functional properties of the composite. pH variations influence the gel structure and this is transduced into fluorescence and color changes of the material. GRAPHICAL ABSTRACT

Preparation, characterization, and antibacterial activity of composite material: Cotton fabric/hydrogel/silver nanoparticles

ABSTRACT A new composite cotton fabric with hydrogel containing silver nanoparticles (AgNPs) has been synthesized by two steps, and simultaneous in situ synthesis of AgNPs under visible light irradiation has been performed. The influence of silver nitrate concentration upon the hydrogel and AgNP properties was studied by colorimetric analysis, scanning electron microscopy, and transmission electron microscopy. The antibacterial activities of the composite materials have been investigated against Acinetobacter johnsonii and Escherichia coli in agar medium and meat-peptone broth. The results showed high inhibition activity toward both test cultures which were better expressed against A. johnsonii.

Synthesis of New Blue Fluorescent Polymerizable 1,8-Naphthalimides and Their Copolymers with Styrene as Sensors for Fe(III) Cations

The synthesis, characterization, and functional properties of two new polymerizable 1,8-naphthalimides (MDs) have been described. Their copolymers with styrene designed to act as a fluorescence PET chemosensor have been investigated. The study also reports the influence of different metal cations (Ag

Detection of Metal Ions and Protons with a New Blue Fluorescent Bis(1,8-Naphthalimide)

The synthesis of a new blue fluorescent bis(1,8-naphthalimide) has been described and its basic photophysical characteristics have been investigated in organic solvents of different polarity. The detection of protons and different metal cations (Ag

Аntimicrobial and anticancer activity of new poly(propyleneamine) metallodendrimers

The synthesis, EPR characterisation and biological evaluation of two new metallodendrimers, i.e. a poly(propyleneamine) dendrimer functionalized at the external surface with 4-bromo-1,8-naphthalimide and conjugated with Cu(II) and Zn(II), was performed with the aim to evaluate their antimicrobial and anticancer activity. The antimicrobial activity was investigated in meat-peptone broth against bacteria B. subtilis and P. aeruginosa, and the yeast C. lipolytica. The results showed that the compounds inhibited effectively the tested pathogens even after their deposition on a textile fabric. Anticancer activity was investigated against three human permanent cell lines from non-small cell lung cancer (A549), triple negative breast cancer (MDA-MB-231) and carcinoma of the uterine cervix (HeLa) in the cu2009=u20090.01–30xa0μM concentration range. The results suggest that these compounds are promising for application in biomedicine as anticancer drugs in the design of new effective preparations. The antimicrobial and anticancer activity may be related to the peculiar structural and dynamical properties revealed for the Cu(II) complexes, by a computer aided analysis of the electron paramagnetic resonance (EPR) spectra. This analysis indicated the formation, at the lowest Cu(II) concentrations, of a flexible rhombic Cu-N4 coordination with the internal amino groups of the dendrimer, which transformed into a Cu2-N4 coordination already at 0.25 equiv. of Cu(II).

Impact of Cu(II) and Zn(II) ions on the functional properties of new PAMAM metallodendrimers

In this study, the synthesis, spectral characterization and in vitro antimicrobial activity of two new metallodendrimers based on the PAMAM dendrimer modified with four 1,8-naphthalimide units are described. The chemical structure of metallodendrimers has been analyzed by FT-IR, UV-Vis, fluorescence, NMR spectroscopy, MS and SEM analysis. The antimicrobial activity of the new compounds has been tested in vitro against different model pathogenic microorganisms. The results showed good inhibitory activity of the compounds better expressed against the tested Gram-positive bacteria and yeasts. Cotton fabrics were treated with each of the dendrimers, and their morphology, antimicrobial activity and biofilm inhibiting potential were investigated. Both metallodendrimers showed stronger antimicrobial and biofilm inhibiting abilities compared to the initial dendrimer ligand.

Synthesis and Characterization of a New PAMAM Metallodendrimer for Antimicrobial Modification of Cotton Fabric

The synthesis and spectral characterization of a new PAMAM metallodendrimer modified with four 4-hexylamino-1,8-naphthalimide units was described. The chemical structure of metallodendrimer has been analyzed with Fourier transform infrared spectroscopy, electronic, nuclear magnetic resonance spectroscopy, and scanning electron microscopy (SEM) analysis. The antimicrobial activity of PAMAM dendrimer and its Zn complex [Zn2(D)(NO3)4] was investigated in agar medium and in meat-peptone broth against several pathogenic bacteria and yeasts. The antimicrobial screening showed good inhibition activity of the compounds better expressed against the test Gram-positive bacteria and yeasts. The antimicrobial efficacy of cotton fabrics treated with each of the dendrimers was evaluated, and their anti-adhesive and biofilm inhibiting potential was analyzed by SEM. The complex [Zn2(D)(NO3)4] showed stronger antimicrobial and biofilm inhibiting abilities than those of the ligand. The cytotoxicity effect of the dendrimers was also investigated in vitro in model HEp-2 cell line.

Spectral Analysis of Poly(propyleneamine) Dendrimers Peripherally Modified with 1,8-Naphthalimides

Seven newly synthesized poly(propyleneamine) dendrimers, modified with 1,8-naphthalimides, have been investigated by infrared, UV-vis, and fluorescence spectroscopy. The influence of the nature of the substituents at the C-4 position of the naphthalene ring on the spectral properties of the dendrimers is discussed.