Electrochemiluminescence Of CdZnTeS Quantum Dots And Its Biosensing Applications

Electrochemiluminescence?ECL?was favored by researchers because of its advantages including low background signal,low cost,high sensitivity and easy to operate.Since the 21st century,a new kind of nanomaterial-quantum dots?QDs?gradually entered the stage of ECL.Various QDs-based ECL sensors have been constructed and its applications cover medicine,environment,energy,biology,etc.However,the application of QDs-based ECL sensors in bioanalysis still existed many problems,mainly focused on the following three aspects:?1?The ECL efficiencies of ordinary QDs were far lower than that of traditional ECL luminescence reagents,therefore,it is urgent to synthesize new nanomaterials to replace the traditional ECL illuminants in bioanalysis;?2?There were very few reports about QDs ECL imaging analysis,so it is a module that worth exploring,and it is also a part that needs to be focused on for a long period of time in the future;?3?Simultaneous detection can simplify the operation steps and save analysis time.Consequently,it is necessary to design more methods for multi-component detection to meet actual demands.Based on this,a series of exploratory experiments based on the ECL strategy of QDs were carried out for the visual analysis and simultaneous detection of tumor markers.The main content of this paper includes the following three parts:1.CdZnTeS QDs based ECL image immunoanalysisIn this chapter,CdZnTeS QDs were prepared firstly,and their ECL properties and ECL efficiencies were studied in detail.An immunosensor was constructed to detect alpha-fetoprotein?AFP?and cancer antigen 125?CA125?by using CdZnTeS QDs as signal tags,which were equipped with strong ECL signals.Under optimal detection conditions,the concentrations of AFP and CA125 can be analyzed by visualized ECL images.At a signal-to-noise ratio of 3,the detection limits of AFP and CA125 were 0.1 ng/mL and 6 U/mL,respectively.Furthermore,a lower detection limit can be obtained via direct detection by photomultiplier tube?PMT?.The detection limits of AFP and CA125 were 0.1 fg/mL and0.03 mU/mL,respectively.Finally,the commercialized enzyme-linked immunosorbent assay?ELISA?was used to measure AFP and CA125 in human serum samples.The test results indicated that CdZnTeS QDs-based ECL biosensors had potential applications for rapid biomedical screening and clinical diagnosis.2.CdZnTeS QDs based ECL immunosensor for simultaneous detection of AFP and CA125CdZnTeS QDs with different fluorescence emission and no fluorescence interference were labeled with secondary antibodies of AFP and CA125,Fe₃O₄@SiO₂ nanoparticles were used to immobilize the primary antibodies.The ECL immunosensor was constructed to simultaneously detect two important tumor markers on hepatoma cells,which called AFP and CA125.Simultaneous detection of AFP and CA125 was achieved by means of 525 nm and650 nm filters,respectively.The detection limits were 3 pg/mL for AFP and 0.1 U/mL for CA125.It is known that the developed ECL immunosensor possessed reliable practical application ability by serum sample analysis.3.Quantitative detection of severe fever with thrombocytopenia syndrome virus via ECL immunoassayQuantitative and sensitive detection of severe fever with thrombocytopenia syndrome virus?SFTSV?was achieved for the first time by using ECL technology.A sandwich immunosensor was prepared by adopting Fe₃O₄@SiO₂ as the magnetic sensing platform and CdZnTeS QDs as labels.The constructed ECL immunosensor had excellent detection ability for SFTSV with a detection limit of 0.003 fg/mL,which was the lowest detection limit in the currently reported quantitative methods.In addition,SFTSV immunosensors owned long-term stability,good reproducibility and high specificity.F inally,the analysis of SFTSV in human serum samples showed that the ECL immunosensor behaved broad application prospects in clinical diagnosis.