Reactivity towards singlet oxygen of propofol inside liposomes and neuronal cells

Abstract

Singlet oxygen ( 1 O 2 ), a reactive oxygen species, has been found to be implicated in many cellular events and pathological disorders. Herein, we investigated the reactivity of 1 O 2 towards the anaesthetic agent propofol (PPF) encapsulated within DMPC liposomes. By time resolved luminescence, the rate constant of 1 O 2 quenching by PPF was evaluated, depending on the location of the sensitizer, with following values: 1.35 T 0.05 Â 10 7 M À1 s À1 for deuteroporphyrin (as embedded source) and 0.8 T 0.04 Â 10 7 M À1 s À1 for uroporphyrin (as external source), respectively. The nature of the oxidation product, resulting from the reaction of 1 O 2 with PPF, was determined using absorption and HPLC techniques. Finally, the in vitro protective effect of PPF towards the 1 O 2 -induced neuronal cell toxicity was evaluated in terms of cell viability. D

Mechanisms of lysophosphatidylcholine‐induced demyelination: A primary lipid disrupting myelinopathy

“…Liposomes were prepared by resuspending in PBS lipid films made of either 6.5 mM egg phosphatidylcholine (PC) or 6.5 mM PC with 0.325 mM egg LPC (both Sigma). To obtain unilamellar vesicles, these solutions were passed 10 times through an extruder (Lipex Biomembrane, Vancouver, Canada) containing a pile of two polycarbonate membrane filters with 100 nm pore diameter (Whatman) according to a known protocol (Heyne et al, ). To ensure solubility of different acyl chain LPC molecules, the LPC was initially dissolved in chloroform, which was removed under reduced pressure.…”

High Stokes Shift Anilido‐Pyridine Boron Difluoride Dyes

“…Because of their planarity, hydrophobicity, and charge neutrality, BODIPY dyes have been used as probes for biological membrane function and dynamics 20. The efficacy of the anilido‐pyridine dyes as probes for investigating membrane properties was assessed in unilamellar liposomes prepared from pure dimyristoylphosphatidylcholine (DMPC)21 using dye 3 a through a spectroscopic titration technique. The efficient partitioning of the dye into the lipid bilayer is demonstrated by a shift of the maximum emission from 536 nm in water to 482 nm in the presence of the liposomes, along with a significant increase in the relative fluorescence intensity of around 70 fold.…”

High Stokes Shift Anilido‐Pyridine Boron Difluoride Dyes

“…[20] The efficacy of the anilido-pyridine dyes as probes for investigating membrane properties was assessed in unilamellar liposomes prepared from pure dimyristoylphosphatidylcholine (DMPC) [21] using dye 3 a through a spectroscopic titration technique. The efficient partitioning of the dye into the lipid bilayer is demonstrated by a shift of the maximum emission from 536 nm in water to 482 nm in the presence of the liposomes, along with a significant increase in the relative fluorescence intensity of around 70 fold.…”