1 palmitoyl 2 oleoyl phosphatidylglycerol popg

The lipid vesicles were prepared using standard procedures45 . The phospholipids 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) and 1-palmitoyl-2-oleoyl-phosphatidylglycerol (POPG) were purchased from Avanti Polar Lipids (Birmingham, AL). The correct amounts of POPC or POPC:POPG (3:1 mole:mole) were dissolved and mixed in dichloromethane. The solvent was removed with a rotary evaporator; the resulting thin film dried in vacuum for at least one hour to remove the residual solvent and then hydrated with a 10 mM Tris-HCl buffer solution (pH 8.0) or 10 mM phosphate buffer (pH 7.0). Large unilamelar vesicles (LUVs) were obtained by extruding the suspension eleven times through two 100 nm polycarbonate membranes in a LiposoFast^® extrusion system (Avestin Inc., Ottawa, ON, Canada). Entrapment of carboxyfluorescein (CF) in 1 mM LUVs was carried out by hydrating a thin film with a buffer containing 10 mM Tris–HCl, pH 8.0, and 10 mM CF. Free CF was removed by passing 1 mL of the extruded LUVs through a Sephadex-G25 column (1.2 cm × 20 cm) and elution with 10 mM Tris–HCl, pH 8.0, containing 200 mM NaCl. The LUVs were collected at the initial volume (V_o) and the PC content of the eluted LUVs was determined by phosphorous assay as described in literature46 (link).

The three COEs used in this work (COE-D8, COE-S6 and COE-D6) were synthesized according to previous literature precedent.[40 (link), 45 (link)] 1-Palmitoyl-2-oleoyl-phosphatidylethanolamine (POPE) and 1-palmitoyl-2-oleoyl-phosphatidylglycerol (POPG) were purchased as chloroform stock solutions from Avanti Polar Lipids. The Propidium Iodide and SYTO 9 fluorescent dyes were purchased from Invitrogen as solid stocks. Four S. aureus strains were used in this study, including two susceptible strains (S. aureus 25923 and S. aureus 29213) and two resistant strains (MRSA BAA-40 and ORSoA S. aureus>). MHB (Mueller Hinton Broth, BD BLL) media and (1×) PBS (Phosphate buffered saline, pH = 7.2) were prepared and autoclaved before use. The 3T3 cell line was used as a model mammalian cell in the in vitro cytotoxicity measurements. Fluorescent micrographs were captured using a Leica SP8 confocal microscope. Scanning electron microscopy (SEM) was performed using an FESEM (JEOL JSM-6700F) instrument for cellular morphology characterizations. Differential scanning calorimetry (DSC) curves of vesicle solutions were measured using a Nano DSC instrument (TA Instruments) at heating and cooling rates of 1°C min⁻¹.

CL from bovine heart and 1-palmitoyl-2-oleoyl-phosphatidylglycerol (POPG) were derived from Avanti Polar Lipids Inc. (Alabaster, AL, US) in the form of lyophilized powder. Yeast ubiquinone-6 was also from Avanti. Ubiquinone-10 and α-tocopherol were bought from Sigma-Aldrich (St. Louis, MO, US). Sodium borohydride and chloroform (99.8%) were purchased from Roth (Karlsruhe, Germany). Chemicals for buffer solutions were ordered from Sigma-Aldrich or Roth. Mini-Extruder and the porous membranes were supplied by Avanti. Azo initiator 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), or MeO-AMVN, was delivered by Wako Pure Chemical Industries (Osaka, Japan). HPMC was a gift of Dr. Vitaly Roginsky. Diverse triphenylphosphonium-containing quinone-based antioxidants (see Figure 2) were synthesized in their oxidized (quinone) forms as previously described [63 (link)].