Serial multiple crossed immunoelectrophoresis at a microscale: A stamp-sized 2D immunoanalysis of protein C3 activation caused by nanoparticles.

Crossed immunoelectrophoresis (C-IE) is used to detect and quantify specific proteins. An application allowed the evaluation of complement system activation by nanomaterials. The work aimed to improve the C-IE toward a higher throughput and less tedious method. A new concept was implemented to prepare and run agarose gels. The first and the second dimension of electrophoresis were performed on a single gel plate, prepared before the beginning of the analysis. Several samples were migrated simultaneously on the same migration line. Up to 35 analyses were run at once, providing stamp-sized electrophoregrams (2.8 × 3 cm(2) ) maintaining the performance of the original method performed on 5 × 7 cm(2) gel slabs. Robustness and precision of the method were demonstrated through a validation approach using ANOVA. Handling, experimental duration, amount of reagents, and overall cost of one analysis were considerably reduced compared to the original method. With the same equipment, seven times more analyses can be performed in one run. C-IE can be used to analyze many types of proteins. The new experimental modalities were suitable for the application developed in the present work that was to evaluate activation of protein C3 of the complement system triggered by nanomaterials.

Match of Solubility Parameters Between Oil and Surfactants as a Rational Approach for the Formulation of Microemulsion with a High Dispersed Volume of Copaiba Oil and Low Surfactant Content.

PURPOSE: Aim was to formulate oil-in-water (O/W) microemulsion with a high volume ratio of complex natural oil, i.e. copaiba oil and low surfactant content. The strategy of formulation was based on (i) the selection of surfactants based on predictive calculations of chemical compatibility between their hydrophobic moiety and oil components and (ii) matching the HLB of the surfactants with the required HLB of the oil. METHOD: Solubility parameters of the hydrophobic moiety of the surfactants and of the main components found in the oil were calculated and compared. In turn, required HLB of oils were calculated. Selection of surfactants was achieved matching their solubility parameters with those of oil components. Blends of surfactants were prepared with HLB matching the required HLB of the oils. Oil:water mixtures (15:85 and 25:75) were the titrated with surfactant blends until a microemulsion was formed. RESULTS: Two surfactant blends were identified from the predictive calculation approach. Microemulsions containing up to 19.6% and 13.7% of selected surfactant blends were obtained. CONCLUSION: O/W microemulsions with a high volume fraction of complex natural oil and a reasonable surfactant concentration were formulated. These microemulsions can be proposed as delivery systems for the oral administration of poorly soluble drugs.

Fluorescence microscopy coupled to electrochemistry: a powerful tool for the controlled electrochemical switch of fluorescent molecules.

The first-time coupling of fluorescence microscopy with a three-electrode electrochemical cell is described and applied to the investigation of a controlled-potential redox switch of organic fluorophores such as tetrazine derivatives.

Scale-up of nanoemulsion produced by emulsification and solvent diffusion.

The scale-up of nanoemulsions (NEs) produced by emulsification and solvent diffusion process was successfully achieved in the present work. Up to 1500 mL of NEs were produced with olive oil, castor oil, almond oil, or Arlamol™ E by using a Y-shaped mixer device. NE droplet sizes were significantly modulated from 290 to 185 nm by changing the process parameters without modification of the formulation composition. Smaller NE droplet sizes were obtained by (1) decreasing the internal diameter of the Y-mixer from 5 to 0.8 mm, (2) increasing the flow rates of the organic and the aqueous phases upon mixing, and (3) increasing the temperature of the experiment from 5°C to 40°C. All the results of NE diameters (d(sc) ) expressed as a function of the Reynolds number (Re) and the shear rate inside the Y-mixer (\documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\dot \gamma$\end{document}) showed the existence of typical power-law relationships: d(sc) = 10(2.82) Re(- 0.14) and \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$d_{{\rm sc}} = 10^{2.60} \dot \gamma ^{- 0.06}$\end{document}, respectively. The existence of these power-laws for NE formation by emulsification and solvent diffusion process has never been reported in the literature yet and constitutes a new finding in this work. We definitely proved that the high turbulences created upon NE formation are the most important parameter allowing to decrease droplet size.

Fluorescent nanoparticles as selective Cu(II) sensors.

Latex nanoparticles functionalized with cyclam (1,4,8,11-tetraazacyclotetradecane), a copper chelator, have been doped with a fluorescent dye (BODIPY derivative: 4,4-difluoro-8-(2',4',6'-trimethyl)phenyl-2,6-diethyl-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene). The bulky, hydrophobic fluorophore dissolves within the nanoparticles' polymer core up to a concentration of about 88.4 micromol g(-1). At this concentration the fluorescence yield is about 0.80. Adding Cu2+ ions to the solution decreases the fluorescence because of the energy transfer between the dye and the violet copper cyclam complexes. The response is fast: 90% of the quenching occurs within 1 s. The Cu2+ detection threshold is of 1 nanomolar. No interferences were observed with zinc and nickel ions.