等电点
牛血清白蛋白
Zeta电位
化学
石英晶体微天平
胶体金
表面电荷
结合常数
位阻效应
纳米颗粒
变性(裂变材料)
胶体
结晶学
无机化学
分析化学(期刊)
色谱法
结合位点
吸附
核化学
立体化学
有机化学
物理化学
纳米技术
材料科学
生物化学
酶
作者
Scott H. Brewer,Wilhelm R. Glomm,Marcus C. Johnson,Magne Knag,Stefan Franzen
出处
期刊:Langmuir
[American Chemical Society]
日期:2005-08-20
卷期号:21 (20): 9303-9307
被引量:855
摘要
The interaction of bovine serum albumin (BSA) with gold colloids and surfaces was studied using zeta-potential and quartz crystal microbalance (QCM) measurements, respectively, to determine the surface charge and coverage. The combination of these two measurements suggests that BSA binding to gold nanoparticles and gold surfaces occurs by an electrostatic mechanism when citrate is present. The binding of BSA to bare gold is nearly two times greater than the binding of BSA to a citrate-coated gold surface, suggesting that protein spreading (denaturation) on the surface may occur followed by secondary protein binding. On the other hand, binding to citrate-coated gold surfaces can be fit to a Langmuir isotherm model to obtain a maximum surface coverage of (3.7 +/- 0.2) x 10(12) molecules/cm(2) and a binding constant of 1.0 +/- 0.3 microM(-1). The zeta-potential measurements show that the stabilization of colloids by BSA has a significant contribution from a steric mechanism because the colloids are stable, even at their isoelectric point (pI approximately 4.6). To be consistent with the observed phenomena, the electrostatic interactions between BSA and citrate must consist of salt-bridges, for example, of the carboxylate-ammonium type, between the citrate and the lysine on the protein surface. The data support the role of strong electrostatic binding but do not exclude contributions from steric or hydrophobic interactions with the surface adlayer.
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