Xing Yuqian, Han Juan, Wu Xu, Pierce David T, Zhao Julia Xiaojun
Department of Chemistry, University of North Dakota, Grand Forks, North Dakota 58202, USA.
Analyst. 2021 Jan 7;145(24):7932-7940. doi: 10.1039/d0an01019g.
An ultrasensitive and versatile assay for biomarkers has been developed using graphene/gold nanoparticles (AuNPs) composites and single-particle inductively-coupled plasma/mass spectrometry (spICP-MS). Thrombin was chosen as a model biomarker for this study. AuNPs modified with thrombin aptamers were first non-selectively adsorbed onto the surface of graphene oxide (GO) to form GO/AuNPs composites. In the presence of thrombin, the AuNPs desorbed from the GO/AuNPs composites due to a conformation change of the thrombin aptamer after binding with thrombin. The desorbed AuNPs were proportional to the concentration of thrombin and could be quantified by spICP-MS. By counting the individual AuNPs in the spICP-MS measurement, the concentration of thrombin could be determined. This assay achieved an ultralow detection limit of 4.5 fM with a broad linear range from 10 fM to 100 pM. The method also showed excellent selectivity and reproducibility when a complex protein matrix was evaluated. Furthermore, the diversity and ready availability of ssDNA ligands make this method a versatile new technique for ultrasensitive detection of a wide variety of biomarkers in clinical diagnostics.
利用石墨烯/金纳米颗粒（AuNPs）复合材料和单颗粒电感耦合等离子体质谱（spICP-MS）开发了一种用于生物标志物的超灵敏且通用的检测方法。本研究选择凝血酶作为模型生物标志物。首先将用凝血酶适配体修饰的AuNPs非选择性地吸附到氧化石墨烯（GO）表面，形成GO/AuNPs复合材料。在存在凝血酶的情况下，由于凝血酶适配体与凝血酶结合后构象发生变化，AuNPs从GO/AuNPs复合材料上解吸。解吸的AuNPs与凝血酶浓度成正比，可通过spICP-MS进行定量。通过在spICP-MS测量中对单个AuNPs进行计数，可以确定凝血酶的浓度。该检测方法实现了4.5 fM的超低检测限，线性范围从10 fM到100 pM。当评估复杂蛋白质基质时，该方法还显示出优异的选择性和重现性。此外，单链DNA配体的多样性和易于获得性使该方法成为临床诊断中用于超灵敏检测多种生物标志物的通用新技术。
