Gold nanoparticles decorated with oligo(ethylene glycol) thiols: surface charges and interactions with proteins in solution.
Gold nanoparticles decorated with oligo(ethylene glycol) thiols: surface charges and interactions with proteins in solution.
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DOI：
10.1016/j.jcis.2014.03.052
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发表时间：
2014-07
影响因子：
9.9
通讯作者：
Moritz Schollbach;Fajun Zhang;F. Roosen‐Runge;M. Skoda;R. Jacobs;F. Schreiber
中科院分区：
文献类型：
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作者：
Moritz Schollbach;Fajun Zhang;F. Roosen‐Runge;M. Skoda;R. Jacobs;F. Schreiber
我们利用电泳和动态光散射（ELS和DLS）研究了低聚乙二醇（OEG）硫醇自组装单层（SAM）涂层金纳米颗粒（AuOEG）及其与溶液中蛋白质的相互作用。结果与聚乙二醇（PEG）硫醇包覆的AuNPs （AuPEG）进行了比较。我们发现AuOEG和AuPEG颗粒都携带低净负电荷，并且非常稳定（保持一年以上），但长期老化或透析会降低稳定性。将修饰后的AuNPs与牛血清白蛋白（BSA）混合后，其有效尺寸和ζ电位保持不变，表明胶体表面不吸附BSA。然而，当与溶菌酶混合时，ζ电位值随着蛋白质浓度的增加而增加，并导致电荷反转，表明溶菌酶在胶体表面吸附。胶体溶液在零电荷附近变得不稳定，在DLS测量中显示出一个簇峰。在加入溶菌酶后，AuPEG溶液表现出类似的电荷反转，但在所有实验条件下溶液都是稳定的，可能是由于PEG的强空间效应。用离心清洗蛋白质结合的胶体，只能去除部分吸附的溶菌酶分子，表明有少数蛋白质强烈吸附在胶体上。胶体表面的有效电荷倒置和相当强的溶菌酶结合可能表明，除了在SAM-water界面形成的电荷外，胶体表面还存在蛋白质可接近的缺陷。这一表面电荷和稳定性的研究结果揭示了SAM包被AuNPs与蛋白质的相互作用及其应用。
We have studied oligo(ethylene glycol) (OEG) thiol self-assembled monolayer (SAM) coated gold nanoparticles (AuOEG) and their interactions with proteins in solutions using electrophoretic and dynamic light scattering (ELS and DLS). The results are compared with poly(ethylene glycol) (PEG) thiol coated AuNPs (AuPEG). We show that both AuOEG and AuPEG particles carry a low net negative charge and are very stable (remaining so for more than one year), but long-term aging or dialysis can reduce the stability. If the decorated AuNPs are mixed with bovine serum albumin (BSA), both effective size and zeta-potential of the AuNPs remain unchanged, indicating no adsorption of BSA to the colloid surface. However, when mixed with lysozyme, zeta-potential values increase with protein concentrations and lead to a charge inversion, indicating adsorption of lysozyme to the colloid surface. The colloidal solutions of AuOEG become unstable near zero charge, indicated by a cluster peak in the DLS measurements. The AuPEG solutions show similar charge inversion upon addition of lysozyme, but the solutions are stable under all experimental conditions, presumably because of the strong steric effect of PEG. Washing the protein bound colloids by centrifugation can remove only part of the adsorbed lysozyme molecules indicating that a few proteins adsorb strongly to the colloids. The effective charge inversion and rather strongly bound lysozyme on the colloid surface may suggest that in addition to the charges formed at the SAM–water interface, there are defects on the surface of the colloid, which are accessible to the proteins. The results of this study of surface charge, and stability shed light on the interaction with proteins of SAM coated AuNPs and their applications.