Determination of the surface potential of two-dimensional crystals of bacteriorh

2019-10-24 03:00:38

pH potential surface crystals constant

责任者: Hartley, P.;Matsumoto, M.;Mulvaney, P. 单位: Sch. of Chem., Melbourne Univ., Parkville, Vic., Australia 来源出处: Langmuir(Langmuir (USA)),1 Sept. 1998,14(18):5203-9 摘要: The interaction forces between a silica sphere and two-dimensional bacteriorhodopsin crystals (bR) were measured in NaNO3 solutions at different pH values, and at two electrolyte concentrations. Using the known ξ potential for the silica sphere as a function of pH, the surface potential of the bR crystals could be determined. The isoelectric point (iep) was found to be pH 4.3±0.5. The crystals had a uniform thickness on substrates of 5.2±0.5 nm, and the Hamaker constant for the bR-H2O-SiO2 system was estimated to be 0.5-1.0×10-20 J at pH values near the iep. Analysis of the force curves suggested that the surface charge on the protein surface remained constant during approach of the silica colloid probe 关键词: atomic force microscopy;proteins;surface potential;surface structure;surface potential;two-dimensional crystals;bacteriorhodopsin;AFM;NaNO3 solutions;pH value;electrolyte concentration;isoelectric point;Hamaker constant;force curves