Synteza i właściwości antybakteryjne czwartorzędowej amoniowej pochodnej polietylenoiminy

The quaternary derivative of branched polyethylenimine (bPEI-met) was synthesized and its antibacterial activity against Gram-positive bacterium (Staphylococcus aureus) and Gram-negative bacterium (Escherichia coli) was studied. The values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of bPEI-met against mentioned bacteria were determined. These indicated that bPEI-met could be considered as an effective alternative to antibiotics for the treatment of selected bacterial strains. The results obtained can be useful in search for drugs allowing treatment of antibiotic resistant bacterial strains.Zsyntetyzowano czwartorzędową amoniową pochodną rozgałęzionej polietylenoiminy (bPEI-met) i badano jej działanie antybakteryjne przeciwko bakteriom Gram-dodatnim na przykładzie gronkowca złocistego (Staphylococcus aureus) i Gram-ujemnym na przykładzie pałeczki okrężnicy (Escherichia coli). Wyznaczono wartości minimalnego stężenia hamującego (MIC) i minimalnego stężenia bakteriobójczego (MBC) bPEI-met w stosunku do obu wymienionych szczepów bakterii. Wyniki tych badań sugerują, że bPEI-met może być rozważana jako alternatywa dla antybiotyków w zwalczaniu wybranych szczepów bakterii, szczególnie tych, które charakteryzują się antybiotykoopornością

Porphyrin-nanoclay photosensitizers for visible light induced oxidation of phenol in aqueous media

A new type of hybrid photosensitizer (Po-C30B) was obtained by efficient adsorption of a 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (Po) by Cloisite 30B (C30B)-a monotallow bis(hydroxyethyl)ammonium-modified montmorillonite clay-from acidic solution in methanol. Structural and spectroscopic properties of Po-nanoclay photosensitizer were determined using X-ray diffraction, laser scanning fluorescence confocal microscopy, and electronic absorption/emission spectroscopies. Po is present not only at the surface of the nanoclay but also in the interior of the Po-C30B hybrid material. The obtained material was found to be an efficient photosensitizer for the oxidation of phenol in aqueous solution under irradiation with the visible light (λ > 470 nm). The mechanism and the quantum yield of that process were shown to be strongly pH-dependent. They were controlled by the acid-base equilibria of porphyrin associated with imine N-protonation as well as by the ionization of the phenol molecule. The quantitative information regarding these dependencies was obtained. The values of K3 and K4 acid-base equilibrium constants were determined (pK3 = 5.88 and pK4 = 2.46) from the absorption spectra recorded during acid-base titration and using an evolutionary factor analysis with the mathematical model including dicationic (H2Po2+), monocationic (HPo+), and neutral (Po) porphyrin forms. They were used to evaluate the importance of these forms in singlet oxygen generation by Po-C30B under defined pH conditions. Moreover, the hybrid photosensitizer can be used repeatedly, which makes it possible to use it in industrial applications