Synthesis and aggregation behaviour of a new sultaine surfactant.

The aggregation properties of a new sultaine surfactant have been studied in buffered aqueous solution at pH 7.4 under controlled condition of osmolarity. Spontaneously formed sultaine vesicles with a mean diameter of about 1 µm can be observed by optical microscopy. The phase behaviour of the surfactant has been investigated by differential scanning calorimetry (DSC) and Nile Red fluorescence. Two critical vesicular concentrations (CVC(1) and CVC(2)) have been fluorimetrically measured, by using pyrene and Nile Red as the fluorescent probes. The two populations of vesicles behave differently as a consequence of their size. The stability of extruded large unilamellar vesicles (LUV) formed slightly above the CVC(1) has been evaluated in the temperature range 25-75°C by following the rate of spontaneous release of entrapped 5(6)-carboxyfluorescein (CF). The stability of the same vesicles at 70°C has also been investigated under osmotic stress obtained by adding NaCl or sucrose to the bulk solution. At a sultaine concentration above the CVC(2) LUV tend to associate and form stable larger closely packed aggregates as suggested by Dynamic Laser Light Scattering and rheological measurements.

Ibuprofen and glutathione conjugate as a potential therapeutic agent for treating Alzheimer's disease.

Non-steroidal anti-inflammatory drugs (NSAIDs) and antioxidant therapy might protect against the development of Alzheimer's disease (AD). In the present work, we synthesized a molecular combination of glutathione (GSH) and ibuprofen (IBU) via an amide bond and investigated its potential for targeted delivery of the parent drugs to neurons, where cellular oxidative stress and inflammation are related to AD. Evaluation of its physicochemical and in-vitro antioxidant properties indicated that compound 1 exhibits good stability toward human plasma enzymatic activity, and, like GSH, displays in-vitro free radical scavenging activity in a time and concentration-dependent manner. The new compound was also assessed by infusion in a rat model for Alzheimer's disease for its potential to antagonize the deleterious structural and cognitive effects of ß-amyloid(1-40). In behavioral tests of long-term spatial memory, animals treated with codrug 1 performed significantly better than those treated with ß-amyloid (Aß) peptide. Histochemical findings confirmed the behavioral data, revealing that Aß protein was less expressed in cerebral cortex treated with 1 than that treated with IBU. Taken together, the present findings suggest that conjugate 1 treatment may protect against the oxidative stress generated by reactive oxygen species (ROS) and the cognitive dysfunction induced by intracerebroventricular (i.c.v.) infusion of Aß(1-40) in rats, and thus that codrug 1 could prove useful as a tool for controlling AD induced cerebral amyloid deposits and behavioral deterioration.

Ibuprofen and lipoic acid diamides as potential codrugs with neuroprotective activity.

Current evidences support the hypothesis that non-steroidal anti-inflammatory drugs (NSAIDs) and antioxidant therapy might protect against the development of Alzheimer's disease (AD). In the present work, our attention was focused on ibuprofen (IBU) used in clinical trails to prevent Alzheimer's disease, and (R)-alpha-lipoic acid (LA) considered as a potential neuroprotective agent in AD therapy. In particular, we investigated a series of lipophilic molecular combinations obtained by joining (R)-alpha-lipoic acid and ibuprofen via an amide bond. These new entities might allow targeted delivery of the parent drugs to neurons, where cellular oxidative stress and inflammation seem related to Alzheimer's disease. Our study included the synthesis of conjugates 1-3 and the evaluation of their physicochemical and in-vitro antioxidant properties. The new compounds are extremely stable in aqueous buffer solutions (pH = 1.3 and 7.4), and in rat and human plasma they showed a slow bioconversion to ibuprofen and (R)-alpha-lipoic acid. Codrugs 1-3 displayed in vitro free radical scavenging activity and were hydrolyzed more rapidly in brain tissue than in rat serum indicating that these new entities might allow targeted delivery of the parent drugs to neurons. The immunohistochemical analysis of Abeta (1-40) protein showed that Abeta-injected cerebral cortices treated with ibuprofen or compound 1 showed few plaques within capillary vessels and, in particular, Abeta (1-40) protein was less expressed in codrug-1-treated than in ibuprofen-treated cerebral cortex.

Microwave-assisted functionalization of carbon nanostructures in ionic liquids.

The effect of microwave (MW) irradiation and ionic liquids (IL) on the cycloaddition of azomethine ylides to [60]fullerene has been investigated by screening the reaction protocol with regard to the IL medium composition, the applied MW power, and the simultaneous cooling of the system. [60]Fullerene conversion up to 98 % is achieved in 2-10 min, by using a 1:3 mixture of the IL 1-methyl-3-n-octyl imidazolium tetrafluoroborate ([omim]BF(4)) and o-dichlorobenzene, and an applied power as low as 12 W. The mono- versus poly-addition selectivity to [60]fullerene can be tuned as a function of fullerene concentration. The reaction scope includes aliphatic, aromatic, and fluorous-tagged (FT) derivatives. MW irradiation of IL-structured bucky gels is instrumental for the functionalization of single-walled carbon nanotubes (SWNTs), yielding group coverages of up to one functional group per 60 carbon atoms of the SWNT network. An improved performance is obtained in low viscosity bucky gels, in the order [bmim]BF(4)> [omim]BF(4)> [hvim]TF(2)N (bmim=1-methyl-3-n-butyl imidazolium; hvim=1-vinyl-3-n-hexadecyl imidazolium). With this protocol, the introduction of fluorous-tagged pyrrolidine moieties onto the SWNT surface (1/108 functional coverage) yields novel FT-CNS (carbon nanostructures) with high affinity for fluorinated phases.

Viscoelastic properties of Staphylococcus aureus and Staphylococcus epidermidis mono-microbial biofilms.

The viscoelastic properties of mono-microbial biofilms produced by ocular and reference staphylococcal strains were investigated. The microorganisms were characterized for their haemolytic activity and agr typing and the biofilms, grown on stainless steel surface under static conditions, were analysed by Confocal Laser Scanning Microscopy. Static and dynamic rheometric tests were carried out to determine the steady-flow viscosity and the elastic and viscous moduli. The analysed biofilms showed the typical time-dependent behaviour of viscoelastic materials with considerable elasticity and mechanical stability except for Staphylococcus aureus ATCC 29213 biofilm which showed a very fragile structure. In particular, S. aureus 6ME biofilm was more compact than other staphylococcal biofilms studied with a yield stress ranging between 2 and 3Pa. The data obtained in this work could represent a starting point for developing new therapeutic strategies against biofilm-associated infections, such as improving the drug effect by associating an antimicrobial agent with a biofilm viscoelasticity modifier.