ABSTRACT
Photophysical and in vitro photocytotoxicity studies were performed for the photosensitizer Dimegine, a disodium salt 2.4-di(alpha-methoxyethyl)-deuteroporphyrin-IX with very low systemic toxicity. The singlet oxygen and luminescence quantum yield were ΦΔ = 0,65 ± 0,06, and Φƒ=0,11 ± 0,01 respectively, and were independent of the excitation wavelength. The photobleaching coefficients for Dimegine dissolved in phosphate buffer (pH 7.4), and DMEM medium at concentration 2 µM/l and in phosphate buffer (pH 7.0) at concentration 10 µM/l were 16·10-5, 9·10-5 and 2·10-5 respectively. In vitro cellular distribution and photocytotoxicity was studied in two human (U87 - primary glioblastoma and HT1376 - bladder cancer) and two rat cell lines (RG2 - glioma, and AY27 - bladder carcinoma). Fluorescence microscopy analysis shows primary Dimegine accumulation as small fluorescent inclusion bodies around the nuclei, suggesting an apoptotic over a necrotic cell death mechanism. The PDT efficacy was slightly higher for the rat cell lines over the human-derived cell lines, with LD50 values of 2,5 µM/l, 2.8 µM/l, 4.5 µM/l, 2.8 µM/l using 530 nm excitation wavelength for AY27, RG2, HT1376 and U87 respectively, and 1.8 µM/l, 2 µM/l, 5 µM/l, 2.4 µM/l using 625 nm excitation wavelength for AY27, RG2, HT1376 and U87 respectively. Comparison to literature data showed that Dimegine demonstrated improved phototherapeutic characteristics comparing to PpIX-mediated PDT.
Subject(s)
Deuteroporphyrins/pharmacology , Photochemotherapy/methods , Photosensitizing Agents/pharmacology , Singlet Oxygen/metabolism , Animals , Cell Line, Tumor , Dose-Response Relationship, Drug , Humans , Hydrogen-Ion Concentration , Methylene Blue/pharmacology , Microscopy, Fluorescence , Photobleaching/drug effects , Protoporphyrins/pharmacology , RatsABSTRACT
Immobilization of alpha-amylase from Bacillus subtilis by adsorption on carboxyl polyelectrolytes, copolymers of methacrylic acid and ethylene glycol dimethacrylate, was being investigated depending on the structure of the polymeric matrix. It is demonstrated that cation exchange resins can be successfully used for reversible sorption and immobilization of alpha-amylase. It was found that the more heterogeneous the structure of the polymeric carrier, the higher is reversibility of the enzyme adsorption. The isothermic process of Bac. subtilis alpha-amylase adsorption on copolymers of different structures was studied as well. The equilibrium of the sorption system was proved to be true.
