Jamel-Eddine Belgaied

Five osmium(II) polypyridyl complexes of the general formula [Os(4,7‐diphenyl‐1,10‐phenanthroline)₂L]²⁺ were synthesized as photosensitizers for photodynamic therapy by varying the nature of the ligand L. Thanks to the pronounced π‐extended structure of the ligands and the heavy atom effect provided by the osmium center, these complexes exhibit a high absorption in the near‐infrared (NIR) region (up to 740 nm), unlike related ruthenium complexes. This led to a promising phototoxicity in vitro against cancer cells cultured as 2D cell layers but also in multicellular tumor spheroids upon irradiation at 740 nm. The complex [Os(4,7‐diphenyl‐1,10‐phenanthroline)₂(2,2′‐bipyridine)]²⁺ was found to be the most efficient against various cancer cell lines, with high phototoxicity indexes. Experiments on CT26 tumor‐bearing BALB/c mice also indicate that the Os^II complexes could significantly reduce tumor growth following 740 nm laser irradiation. The high phototoxicity in the biological window of this structurally simple complex makes it a promising photosensitizer for cancer treatment.

Five osmium(II) polypyridyl complexes of the general formula [Os(4,7‐diphenyl‐1,10‐phenanthroline)₂L]²⁺ were synthesized as photosensitizers for photodynamic therapy by varying the nature of the ligand L. Thanks to the pronounced π‐extended structure of the ligands and the heavy atom effect provided by the osmium center, these complexes exhibit a high absorption in the near‐infrared (NIR) region (up to 740 nm), unlike related ruthenium complexes. This led to a promising phototoxicity in vitro against cancer cells cultured as 2D cell layers but also in multicellular tumor spheroids upon irradiation at 740 nm. The complex [Os(4,7‐diphenyl‐1,10‐phenanthroline)₂(2,2′‐bipyridine)]²⁺ was found to be the most efficient against various cancer cell lines, with high phototoxicity indexes. Experiments on CT26 tumor‐bearing BALB/c mice also indicate that the Os^II complexes could significantly reduce tumor growth following 740 nm laser irradiation. The high phototoxicity in the biological window of this structurally simple complex makes it a promising photosensitizer for cancer treatment.

A new catalytic wet peroxide oxidation of ofloxacin antibiotic is presented in this work. The removal was achieved using a biodegradable sodium alginate-iron material. Several parameters were studied such as iron content, drying duration of the catalytic support, temperature, solid amount and initial drug concentration. The process showed a strong oxidative ability; at optimum conditions, a nearly complete removal of the drug (around 98%) has been reached after three h of treatment. A relatively low decrease of support activity (around 10%) has been observed after three successive oxidation runs and a low iron leaching has been detected (1.2% of the incorporated quantity). The removal of the substrate has been also examined in the absence of hydrogen peroxide in order to discriminate between the contributions of simple adsorption and oxidation processes in the drug disappearance. We also discussed the influence of the studied experimental parameters on the removal kinetic.

The construction of a new moxifloxacin (MOX) hydrochloride coated platinum selective electrode based on MOX-tetraphenylborate (MOX-TPB) as electroactive material is described. Plasticized polymeric membranes with a composition of polyvinyl chloride. o-nitrophenyl pentyl ether: MOX-TPB:potassium tetrakis(4-chlorophenyl) borate in the percentage ratio of 30:66:2:2 (%, w:w:w) were selected. The sensor displayed rapid, stable and near-Nernstian response, 57.6 ± 0.6 mV · decade ^-1 , over the concentration range of 2 × 10 ^-6 to 1 × 10 ^-2 mol · L ^-1 . The pH does not affect the performances of the proposed electrode within the pH range 3-5.5. The electrode is proved to have a good selectivity for MOX hydrochloride over some inorganic and organic compounds. The constructed electrode was proved to be successful for the potentiometric titration of MOX cation with TPB solution in raw material and in reconstituted powders containing MOX. The results were validated by comparison with a capillary electrophoresis method.

The hyphenation of CE with MS is nowadays accepted as a powerful analytical approach. As far as ESI, the most common interface, is concerned, one challenge is to provide the most sensitive as well as quantitative information, which is quite a difficult task, as it is linked, among other factors, to suction and dilution effects. In the coaxial ESI configuration, it has been previously demonstrated that suction effect depends on many parameters inherent to the ESI interface geometry, the prevailing ones being the CE capillary protrusion from the interface needle, the sheath liquid (SL) and the overall BGE flow rates and velocity profile. In this paper, dilution effect is studied, as the CE electrolyte is mixed with SL at the interface. Considering peak intensity and efficiency, this effect was studied as a function of the various parameters of the interface (capillary protrusion from the SL tube, nebulizing gas, SL and CE electrolyte flow rates) or of the source (skimmer and ESI voltages, drying gas flow rate and temperature). It appears that the dilution effect seems slightly lower than what can be anticipated from the proportions of the liquid flow rates. This study also indicates that suction effect has to be considered first to better understand the dilution phenomenon, as suction effect leads to an increase in peak intensity, before a dilution effect appears.

The hyphenation of CE with MS is nowadays accepted as a powerful analytical approach. Employing ESI, the most common interface, one challenge is to provide quantitative information, which is quite a difficult task, as it is linked, among other factors, to suction and dilution effects. In the coaxial ESI configuration, the suction effect has been presented in literature as stemming from nebulizing gas (NG) flow rate and drying gas temperature. But as this interface consists in three concentric capillaries, allowing for BGE, sheath liquid (SL) and NG mixing, it is demonstrated herein that other parameters are also involved in this suction effect: the CE capillary protrusion from the interface needle, SL flow rate, and overall BGE flow rate and velocity profile. Whereas NG flow rate is the parameter affecting suction to a greater extent, separation capillary protruding length, SL, and overall BGE flow rate have a significant additional impact on this phenomenon. It is shown that SL flow rate can affect suction differently according to the NG velocity, which may be explained by modification of the Taylor cone geometry. Furthermore, it appears that suction effect is noticeably favored by a parabolic velocity profile of the BGE, again probably due to the Taylor cone shape modification. Finally, the temperature gradient created by the contact between the heated NG and the separation capillary enhances this effect.

A method for a single‐run separation of cationic, anionic, and polyanionic compounds by CE hyphenated to ESI MS (CE‐ESI‐MS) is described. One of the main issues for coupling CE to MS with an ESI source consists in maintaining an electric contact for the electrophoretic separation. This condition is only performed if a liquid flow arising from the separation capillary is directed to the needle, making it coupling‐compatible. This latter situation is incompatible with the separations of polyanionic compounds of higher electrophoretic mobility (in absolute value) than the electroosmotic mobility, performed in bare fused‐silica capillaries under a negative polarity. In this study, several alternative approaches were evaluated to circumvent this difficulty, and applied to the setup of the CE‐MS separation of a mixture containing both cationic and polyanionic compounds, which are synthesis intermediates of contrast agents for medical imaging. Eventually, the detection of the cationic and anionic compounds in a single run could be obtained by either using neutrally coated polymethylsiloxane (DB‐1) capillaries and simultaneously applying a negative voltage polarity and a pressure allowing to compensate for the residual cathodic EOF or by dynamically modifying the inner wall of a bare fused‐silica capillary with a polycationic polymer (hexadimethrine bromide) and using it afterwards under negative voltage polarity.