In Situ Generation of Self-Enhanced Luminophore by β-Lactamase Catalysis for Highly Sensitive Electrochemiluminescent Aptasensor
作者:Guo-Feng Gui、Ying Zhuo、Ya-Qin Chai、Yun Xiang、Ruo Yuan
DOI:10.1021/ac500665b
日期:2014.6.17
This work described a new electrogenerated chemiluminescence (ECL) aptasensor for ultrasensitive detection of thrombin (TB) based on the in situ generating self-enhanced luminophore by β-lactamase catalysis for signal amplification. Briefly, a ruthenium complex (Ru–Amp), including two regions of [Ru(phen)2(cpaphen)]2+ and ampicillin (Amp), was synthesized as a self-enhanced ECL luminophore, which can produce an ECL signal through intramolecular interactions. Then, carbon nanotubes (CNTs) were used for immobilization of Ru–Amp via π–π stacking interactions to form the Ru–Amp@CNTs nanocomposite. Using poly(ethylenimine) (PEI) as a linkage reagent, Au nanocages (AuNCs), owing to their electronic property and large surface areas, were decorated to the CNTs to form the Ru–Amp@CNTs–PEI–AuNCs nanocomposites, which were further used to immobilize thrombin binding aptamer II (TBA II) to form a signal probe (Ru–Amp@CNTs–PEI–AuNCs–TBA II). Through “sandwich” tactics, TBA II bioconjugates, TB and TBA I were immobilized onto the gold nanoparticles modified electrode. Then, with the enzyme catalysis of β-lactamase, a novel self-enhanced ECL luminophore (Ru–AmpA) was in situ produced, which could exhibit a significant enhancement of ECL signal, due to the structure transformation of an amide bond into a secondary amine. A sandwich ECL assay for TB detection was developed with excellent sensitivity of a concentration variation from 1.0 fM to 1.0 pM and a detection limit of 0.33 fM. Therefore, the self-enhanced ECL luminophore, combining the further enhancement by in situ enzymatic reaction, is expected to have potential applications in biotechnology and clinical diagnosis.
这项工作描述了一种新的电化学发光(ECL)适配器,用于超灵敏检测凝血酶(TB),其原理是基于β-内酰胺酶催化原位产生的自增强发光团,用于信号放大。简而言之,一种钌配合物(Ru-Amp)包括两个区域[Ru(苯)2(cpaphen)]2+和氨苄青霉素(Amp),被合成为自增强ECL发光团,可通过分子内相互作用产生ECL信号。然后,碳纳米管(CNTs)通过π-π堆积相互作用固定Ru-Amp,形成Ru-Amp@CNTs纳米复合材料。使用聚(乙二胺)(PEI)作为连接试剂,将Au纳米笼(AuNCs)由于其电子特性和大表面积而装饰到CNTs上,形成Ru-Amp@CNTs-PEI-AuNCs纳米复合材料,进一步用于固定凝血酶结合适配体II(TBA II),形成信号探针(Ru-Amp@CNTs-PEI-AuNCs-TBA II)。通过“三明治”策略,TBA II生物偶联物、TB和TBA I被固定在修饰电极的金纳米颗粒上。然后,在β-内酰胺酶的催化下,原位产生了一种新型的自增强ECL发光团(Ru-AmpA),由于酰胺键转化为仲胺的结构转变,它可以显着增强ECL