Molecular mechanisms of phosphatidylcholine monolayer solidification due to hydroxyl radicals

作者：Groening Andreas; Ahrens Heiko; Ortmann Thomas; Lawrenz Frank; Brezesinski Gerald; Scholz Fritz; Helm Christiane A^*

来源：Soft Matter, 2011, 7(14): 6467-6476.

DOI：10.1039/c1sm05312d

The reaction of L-alpha-1,2-dipalmitoylphosphatidylcholine (DPPC) with hydroxyl radicals (HO(center dot) from Fenton solutions) was investigated using monolayer techniques: isotherms, infrared reflection absorption spectroscopy (IRRAS), grazing incidence X-ray diffraction, X-ray reflection and fluorescence microscopy. The DPPC monolayer is attacked with different HO(center dot) concentrations. The decrease in the lateral pressure was used as a measure of the efficiency of the HO(center dot) attack. With increasing HO(center dot) concentration, the plateau region in the isotherm was shifted to a lower surface pressure; eventually it disappeared. Fluorescence microscopy during the HO(center dot) attack showed that new domains in the condensed phase nucleate immediately. With isotherms and X-ray diffraction we found that the monolayer can be compressed to smaller molecular areas, with a reduced tilt angle of the alkyl chains. IRRAS experiments indicated a partial cleavage of the head group leading to a reduced head group size.

• 出版日期2011