反应详情

Poly(ε-caprolactone) having average Mw 65.000, Sorbitan monostearate (Span®60), and Polysorbate 80 (Tween®80) were obtained from Sigma-Aldrich (St. Louis, USA). All organic solvents used for were HPLC grade purchased from J. T. Baker (Ecatepec, Mexico). Ultrapure water was produced in-house by Milli-Q System (18 MΩ) (Millipore Corporation, Bedford, Mass., USA). Nanoparticles containing citral (3,7-dimethyl-2,6-octadienal), phosphorylethanolamine and/or methyl jasmonate were obtained as follows. First, an oil/water (O/W) emulsion was made by vigorous stirring of oil (10.0 g) and the active compounds, alone or in mixture ranging from 0.05 to 0.50 g, (internal constituents) in water (400 mL) by using a Ultra-Turrax homogenizer (IKA T10 basic Ultra-turrax®, Ika-Werke, Staufen, Germany) at 15,000 rpm by 1 min. In a second step, an organic solution which was prepared by dissolving a polymer (between 0.2 and 2.0 g) in acetone (400 mL) was poured under moderate magnetic stirring, into emulsion phase using a peristaltic pump at 10% (PumpPro TPM 600 55 RPM, Waton-Marlow, Wilmington, UK). After 10 min of stirring, an aqueous solution prepared by dissolving 1.0 g of Tween®80 in water (200 mL) was also poured under moderate magnetic stirring into the emulsion. Again, a peristaltic pump at 10% was used. After complete addition, the reaction mixture was further stirred for 10 min. In the last step, the organic solvent was removed and the volume of nanoparticle dispersion was concentrated to 500 mL under reduced pressure (R-21, Büchi, Switzerland). The O/W emulsion made in the first step was stable even without the polymer. Several different nanoemulsions were prepared and analyzed.