Electrochemical and Surface-Plasmon Correlation of a Serum-Autoantibody Immunoassay with Binding Insights: Graphenyl Surface versus Mercapto-Monolayer Surface
Electrochemical and Surface-Plasmon Correlation of a Serum-Autoantibody Immunoassay with Binding Insights: Graphenyl Surface versus Mercapto-Monolayer Surface
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DOI：
10.1021/acs.analchem.8b01565
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发表时间：
2018-11-06
影响因子：
7.4
通讯作者：
Krishnan, Sadagopan
中科院分区：
文献类型：
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作者：
Premaratne, Gayan;Niroula, Jinesh;Krishnan, Sadagopan
我们在这里展示了表面等离子体和电化学免疫测定之间的皮摩尔亲和力之间的相关性，用于检测血清谷氨酸脱羧酶 65 自身抗体 (GADA)（1 型糖尿病 (T1D) 的生物标志物）与其抗原 GAD-65 的结合。与巯基丙酸 (MPA) 的自组装单层表面相比，在金表面等离子体芯片或电化学阵列上进行羧化（类似于 5.0%）石墨烯修饰的免疫组装可提供显着更大的结合亲和力、更高的灵敏度和更低的检测限。通过共价标记电活性氨基二茂铁来估计相对表面 -COOH 基团表明，石墨苯表面显示出比 MPA 表面更多数量的 -COOH 基团（9 倍）。 X 射线光电子能谱分析表明，石墨烯-COOH 表面上的 C-O 和 C=O 官能团比 MPA 表面上的更多。与普通玻璃表面上的类似涂层相比，金上的石墨烯-COOH涂层表现出类似5.5倍的等离激元信号增强。总之，本文提供了羧化石墨烯与巯基单层免疫组装体的定量比较。此外，我们建议结合常数值可用作临床生物测定大规模生物传感器的可重复且可靠生产的质量控制检查点。
We present here the correlation of picomolar affinities between surface-plasmon and electrochemical immunoassays for the binding of serum glutamic acid decarboxylase 65 autoantibody (GADA), a biomarker of type 1 diabetes (T1D), to its antigen GAD-65. Carboxylated (similar to 5.0%)-graphene-modified immunoassembly on a gold surface-plasmon chip or on an electrochemical array provided significantly larger binding affinity, higher sensitivity, and lower detection limits than a self-assembled monolayer surface of mercaptopropionic acid (MPA). Estimation of the relative surface -COOH groups by covalent tagging of an electroactive aminoferrocene showed that the graphenyl surface displayed a greater number of -COOH groups (9-fold) than the MPA surface. X-ray-photoelectron-spectroscopy analysis showed more C-O and C=O functionalities on the graphene-COOH surface than on the MPA surface. The graphene-COOH coating on gold exhibited similar to 5.5-fold enhancement of plasmon signals compared with a similar coating on a plain glass surface. In summary, this article provides a quantitative comparison of carboxylated graphene with a mercapto-monolayer immunoassembly. Additionally, we propose that the binding-constant value can be useful as a quality-control checkpoint for reproducible and reliable production of large-scale biosensors for clinical bioassays.