Thermal structural evolutions of DMPC-water biomimetic systems investigated by Raman Spectroscopy.

Many cell membranes of living organisms can be represented as phospholipid bilayers immersed into a water environment. The physical-chemical interactions at the membranes/water interface are responsible for the stabilization of the membranes. In addition, the drug efficiency, the pharmaceutical mechanism and the improvement of the drug design can be addressed to the interactions between the membranes-water interface with the drug and to the membrane-drug interface. In this framework, it is important to find membranes models able to simulate and simultaneously simplify the biological systems to better understand both physical and chemical interactions at the interface level. Dimyristoylphosphatidylcholine (DMPC) is a synthetic phospholipid used in order to make Multilamellar Vesicle (MLV), Large Unilamellar Vesicle (LUV) and Giant Unilamellar Vesicle (GUV). In order to understand the mechanisms of vesicle formation, we have analyzed mixtures of DMPC and water by micro-Raman spectroscopy at different temperatures in the range between 10 and 35 °C. Particularly, we analyzed the temperature dependence of the CN vibrational frequency, which appears well correlated to the order degree of the various phases. These investigations, beyond the determination of phospholipid hydrocarbon chains order, provide information about the conformation of the lipid membranes. We have identified the mixture of DMPC/water that is best suited for Raman studies and can be used as an in-vitro model for biological systems. A peculiar frequency shift across the transition gel-ripple-liquid crystalline phases has been proposed as a useful diagnostic marker to detect the "order degree" and subsequently the phases of biomimetic membranes made by DMPC.

Mesomorphism and electrochemistry of thienoviologen liquid crystals.

The thienoviologen series 4,4'-(2,2'-bithiophene-5,5'-diyl)bis(1-alkylpridinium)X2, with = counterion is a new class of electron acceptor materials which show very interesting electrochromic and electrofluorescence properties. Depending on the length, m, of the promesogenic alkyl chains, and on the counterion, thienoviologens might become liquid crystals. Here, we present the mesomorphic behaviour, and the electrochemical and spectroelectrochemical properties in solution of new thienoviologens of the series and (I = iodide; NTf2(-) = bis(tri-fuoromethylsulfonyl)imide) with m = 8, 12. Interestingly, we found that only the compounds are liquid crystals, exhibiting a calamitic behaviour in contrast to the homologous compounds of the series with m = 9-11 and X = NTf2(-), which showed columnar rectangular mesophases. The electrochemical study here reported allowed us to explain for the first time the anomalous behaviour of these thienoviologens already observed in cyclic voltammetry, where two apparently irreversible redox processes occur. This can be explained by a comproportionation reaction in which the neutral species rapidly reduces the dication to the radical-cation, due to its strong reducing power. Electrochemical reduction of the thienoviologens causes electrochromism since a new absorption band, occurring at 660 nm in the electronic spectra, appears with the negative potential bias applied. With a LUMO level of 3.64 eV, similar to those of the C60 and of other n-type materials, these compounds can find applications in several electronics devices, where their liquid crystalline properties can be used to control film morphology and geometry, provided they have good electron mobility.

Low pressure plasma functionalized cellulose fiber for the remediation of petroleum hydrocarbons polluted water.

This work reports the first example of effective purification, at laboratory level, of water polluted by petroleum hydrocarbons, by means of low pressure plasma fluorine grafted cellulose fiber extracted from Spanish Broom. In order to improve the affinity of the cellulosic surface towards water dispersed hydrocarbons, its original hydrophilic character was turned to super-hydrophobic, by a fluorine functionalization. Batch experiments were performed with the aim of studying kinetic and thermodynamic aspects of the adsorption process, as a function of the initial total hydrocarbon load and of the adsorbent amount. The kinetics data showed that the fiber removal efficiency ranged between 80-90% after one minute of contact time, in dependence of the initial hydrocarbon/fiber weight ratio (20-240 mg/g). A maximum adsorption capacity larger than 270 mg/g was estimated by fitting the adsorption isotherm measurements with the Langmuir model. It turned out that the functionalized fiber is capable to perform a significant hydrocarbons removal action if compared to other cellulosic materials reported in the literature. Finally, the efficiency of the plasma modified cellulose fiber, after iterative re-uses, was studied.

Antiproliferative effect of millimeter radiation on human erythromyeloid leukemia cell line K562 in culture: ultrastructural- and metabolic-induced changes.

In the present study we compared the proliferation behavior, the ultrastructural morphology and the glycolitic metabolism of K562 cells irradiated by low-power wide-band millimeter waves, with those of sham-exposed K562 cells (control), maintained in the same culture conditions. The gigaHertz radiation treatments, performed between 53-78 10(9) Hz, induced a noticeable inhibition of the cell proliferation that could be related to relevant ultrastructural changes. Such effects brought the irradiated cell system to lose the homeostasis and to trigger defense/reparatory mechanisms in order to reestablish a new steady state. (13)C-Nuclear magnetic resonance data on the kinetic of glucose metabolism demonstrated that the irradiated cells enhanced the glycolitic aerobic pathway, indicating that such system need to produce an extra-bioenergy. Most of the ATP synthesized served probably to perform the above processes resulting in a significant decrease of the proliferation rate without significant cell death increment.

Orthogonal electronic coupling in multicentre arylamine mixed-valence compounds based on a dibenzofulvene-thiophene conjugated bridge.

Herein we present organic mixed-valence compounds with an innovative H-shape design, where four redox centres are bridged "vertically" via a dibenzofulvene backbone and "horizontally" via a bis-(dibenzofulvene)-thiophene bridge. These compounds are easily oxidized to stable highly charged radical species which show intense intervalence charge transfer transitions in the near infrared region. Interestingly, depending on the position of the arylamine substituents on the bridge, both vertical and horizontal electron transfer pathways can be optically induced.

Early markers of Fabry disease revealed by proteomics.

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by a deficiency of the lysosomal hydrolase α-galactosidase A (α-GalA) that leads to the intra-lysosomal accumulation of globotriaosylceramide (Gb3) in various organ systems. As a consequence, a multisystems disorder develops, culminating in stroke, progressive renal and cardiac dysfunction. Enzyme replacement therapy (ERT) offers a specific treatment for patients affected by FD, though the monitoring of treatment is hindered by a lack of surrogate markers of response. Remarkably, due to the high heterogeneity of the Fabry phenotype, both diagnostic testing and treatment decisions are more challenging in females than in males; thus, reliable biomarkers for Fabry disease are needed, particularly for female patients. Here, we use a proteomic approach for the identification of disease-associated markers that can be used for the early diagnosis of FD as well as for monitoring the effectiveness of ERT. Our data show that the urinary proteome of Fabry naïve patients is different from that of normal subjects. In addition, biological pathways mainly affected by FD are related to immune response, inflammation, and energetic metabolism. In particular, the up-regulation of uromodulin, prostaglandin H2 d-isomerase and prosaposin in the urine of FD patients was demonstrated; these proteins might be involved in kidney damage at the tubular level, inflammation and immune response. Furthermore, comparing the expression of these proteins in Fabry patients before and after ERT treatment, a decrease of their concentration was observed, thus demonstrating the correlation between the identified markers and the effectiveness of the pharmacological treatment.