Desislava Staneva

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.

Synthesis and spectroscopic studies of a new 1,8-naphthalimide dyad as detector for metal cations and protons

A new dyad containing two 1,8-naphthalimides has been synthesized. N,N-Dimetylaminoethylamino group has been used as substituent at C-4 position of the 1,8-naphthalimide chromophore structure. The photophysical characteristics of the dyad have been investigated in organic solvents with different polarity. In acetonitrile solution the newly synthesized dyad enhance its fluorescent intensity in the presence of metal cations (Ni(2+), Co(2+), Cu(2+), Pb(2)(+), Zn(2+), Fe(3+)) and protons due to quenching of photoinduced electron transfer.

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.

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.

Synthesis, spectral characterization, and in vitro antimicrobial activity in liquid medium and applied on cotton fabric of a new PAMAM metallodendrimer

ABSTRACT A new polyamidoamine metallodendrimer modified with eight 1,8-naphthalimide units was synthesized. The Cu(II) complex has been investigated by EPR spectroscopy and it has shown that 17 copper ions have involved in the dendrimer complex. To confirm the presence of metallodendrimers on the cotton surface, scanning electron microscopy characterization has been used. In vitro antimicrobial activity of the metallodendrimer against different pathogens was investigated and compared to the dendrimer ligand free of copper ions. Both dendrimers were deposited on a cotton fabric and antibacterial activity of the treated cotton samples was investigated against model Gram-positive and Gram-negative bacteria. It has been shown that the studied dendrimers reduce bacterial growth and prevent the formation of biofilms. The metallodendrimer showed stronger antimicrobial and biofilm inhibiting abilities than those of the free of Cu(II) ions ligand.

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.

Photophysical Properties of new Polymerizable 1,8-Naphthalimides and their Copolymers with Methylmethacrylate

In this paper we discuss the photophysical properties of some 4-nitro- and 4-allylamino-N-phenyl- 1,8-naphthalimides having different substituents in the phenyl ring, and their copolymers with methylmethacrylate in solid films. The influence of the substituents at the phenyl ring and the environment (methanol or polymer matrix) on the absorption and fluorescence properties is also discussed.