Research And Application Of Electrochemiluminescence Sensor Based On Silver Nanocomposites

Electrochemiluminescence sensor is such an analysis device that combines electrochemiluminescencetechnologywithbiosensortechnology,using electrochemiluminescence intensities as detection signals.Now ECL sensor plays an increasing important role in electrochemical analysis and research,because of its better selectivity,higher sensitivity,rapid analysis,on-line live analysis,etc.The unique properties of noble metals nanomaterials play a very important role in improving the sensitivity of the sensor during the construction process of electrochemical sensors.Compared with other metals,silver nanoparticles,in particular,have been extensively studied due to their excellent optical and electrical conduction properties in the fields of catalysis,electronics,sensing and surface enhanced raman scattering.So the research of silver nanomaterials has attracted more and more attention.This article mainly focuses on the preparation of functionalized silver nanocomposites and their applications in electrochemiluminescence sensors.The specific work is as follows:1.An ultrasensitive electrochemiluminescence sensor for the detection of highly up-regulated in liver cancer?HULC?based on Au@Ag/GQDs as a signal indicatorLiver cancer is one of the factors that threaten human life.Highly up-regulated in liver cancer?HULC?,a kind of long non-coding RNA?lncRNA?,is regarded as a favorable noninvasive biomarker for the early diagnosis of hepatocellular carcinoma?HCC?.So a strategy focused on improving the sensitivity of HULC detection is urgently desired.In this work,a highly sensitive electrochemiluminescent?ECL?sensor was constructed using Au@Ag core-shell nanoparticles/graphene quantum dots?Au@Ag/GQDs?as a signal indicator to detect HULC.GQDs has been widely studied for its advantages such as good water solubility,low toxicity,friendly environment,wide sources of raw materials,low cost and good biocompatibility.Compared with the individual gold or silver nanoparticles,Au@Ag core-shell nanoparticles exhibited large specific surface area,better catalysis and excellent electronic transmission capacity due to the synergistic effect between Au and Ag.Thus,the ECL performance of GQDs could be greatly promoted by Au@Ag core-shell nanoparticles.Under the optimal conditions,this proposed ECL sensor exhibited ultrahigh sensitivity for quantitative detection of HULC with a wide linear range from 1 fM to 5 nM and a low detection limit of 0.3 fM?S/N=3?.These results showed that the sensor was promising for the sensitive detection of lncRNA in clinical application.2.A novel luminol cathodic electrochemiluminescence immunosensor based Gold–silver nanocomposite-functionalized graphene.In this work,gold-silver nanocomposite-functionalized grapheme?GR/Au–Ag?was synthesized by in-situ chemical reduction method.Because of the excellent conductivity,biocompatibility and catalytic properties of Ag NPs and Au NPs,the synergistic effect between metal nanoparticles and grapheme,luminol can produce a strong and stable cathode electrochemical luminescence.The luminescence would reduce when the cancer embryo antigen?CEA?was combined with antibody specifically.As a result,a novel lable-free electrochemiluminescence?ECL?immunosensor was fabricated by using GR/Au–Ag as a platform.Under the optimal conditions,the CEA was determined in the range of 10 pg mL^-1to 100 ng mL^-1with a limit of detection down to 3.34 pg mL^-1?S/N=3?.Moreover,with the excellent sensitivity,selectivity,stability and simplicity,this immunoassay would provide great potential in clinical applications for detection of the CEA.3.An electrochemiluminescence sensor for detecting Carcinoembryonic Antigen based on Ag@SiO₂/Luminol as label.In this study,Ag@SiO₂ core-shell nanoparticles were designed and synthesized,and Luminol molecules were loaded on the surface of Ag@SiO₂ nanoparticles bylayer-by-layer assembly.Ag@SiO₂ nanoparticles not only overcomed the disadvantages such as the poor conductivity of SiO₂,but also a protective layer formed by SiO₂ between Ag NPs and Luminol probe can protect Ag NPs from chemical erosion.At the same time,increasing the surface area of the load luminol molecules.As a result,the labeled probe can produce a stable electrochemical luminescence.A sensitive sandwich-type immunosensor for quantitative detection of carcinoembryonic antigen was constructed based onAg@SiO₂/Luminol as label.This study provided a new approach for improving ECLefficiency and a generic method for designing high-performance nanomaterials.It has great potential in biological analysis and early diagnosis of cancer.