| Electrochemiluminescence(ECL)is a product of electrochemical and chemiluminescence,which has the advantages of high sensitivity,wide linear range,simple instrument and fast analysis speed.It shows performance development prospects in clinical analysis,food analysis,drug analysis and other fields.Ratiometric electrochemiluminescence is an analytical method combining ratiometry and electrochemiluminescence technology,which can effectively reduce the interference of the environment or instrument and improve the accuracy and sensitivity during the detection of complex samples.Accordingly,this artical constructed a series of spatially resolved ratiometric electrochemiluminescence biosensing platforms.During these platforms,some emitters synthesized cuch as CdS QDs,luminol-Au NPs,g-C3N4 NSs,Ru/zinc-oxalate MOF,g-C3N4-Ag and Ru-MOF-Ag to achieved potential-resolved,and combining with a series of signal amplification strategies such as spatial resistance effect,regulatory coreactor effect,resonance energy transfer effect and etching effect to come true accurate and sensitive detection of cancer markers.Specific innovation points and research contents are as follows:1.A spatial-and potential-resolved ratiometric electrochemiluminescent(ECL)immunosensor was developed for prostate specific antigen detection in a label free mode.In the electrochemiluminescence system,CdS quantum dots(CdS QDs)and luminol-Au nanoparticles(luminol-Au NPs)were chosen as the potential-resolved electrochemiluminescence emitters and H2O2 was used as co-reactant.The cathodic signal from CdS QDs modified served as the working signal and the anodic signal from luminol-Au NPs as the reference signal.For prostate specific antigen detection,varied concentration of prostate specific antigen was immobilized on the CdS QDs modified electrode and fixed concentration of the prostate specific antigen was modified on the luminol-Au NPs modified electrode.The prostate specific antigen levels were quantified by the electrochemiluminescence signal ratio of the cathodic and anodic(ECLcathodic/ECLanodic).Under the optimized conditions,the ratio of the cathodic and anodic signals(ECLcathodic/ECLanodic)showed a linear relationship with the logarithm of(C,g/m L)with the concentration of prostate specific antigen ranged from 1.0×10-11 to1.0×10-7 g/m L.The detection limit is 5.0×10-12 g/m L.The contents of prostate specific antigen in seven human serum samples were determined and recoveries were ranged from 80.0%to 107%.The label free electrochemiluminescence immunosensor shows merits of simplicity and reliability in real human serum samples and holds great potential in clinical diagnosis.2.Potential-resolved electrochemiluminescence(ECL)ratiometric analysis have become a research hotspot in bioassays in virtue of the good accuracy,versatility and specificity.The current ECL ratiometry mainly focuses on competition for the one co-reactant or quantitative analysis using a variable signal and a changeless signal,the disorganized change or small difference between the two signals may affect the further accuracy and sensitivity of detection.In this work,we have developed a novel ECL ratiometric sensor based on the bidirectional regulation to two independent co-reaction systems by H2O2.H2O2 as the bidirectional moderator permits the ECL signals of cathode and anode to independent change in opposite trend,which greatly enhances the organization and difference between the two signals.The ratio of two signals is used to realize the quantitative analysis of myoglobin(MyO)with a good linear relationship between log(ECLcathode/ECLanode)and log CMyO at the range from 1.0×10-13 to 1.0×10-7g/m L.The detection limit is 4.0×10-14 g/m L.Furthermore,it showed excellent performance in the determination of MyO in human serum samples.The proposal biosensor provides some developments for sensitive and accurate detection of disease markers.3.In this work,the high-efficient ECL-RET luminescence of g-C3N4-Ag NPs andhigh-efficient electron transfer rate emitter of Ru-MOF-Ag NPs were synthetised by combining bifunctional Ag NPs with g-C3N4 NSs and Ru-MOF.Using above materials as emmiters,a split-type ratiometric sensor was designed based on the spatial separation strategy to come true high-sensitivity detection of target.In this system,the immunological reaction was constructed in 96-well plate.In the presence of MyO,H2O2was produced by enzymic catalytic reaction between GOx and glucose.After that,the generated H2O2 was transfered to WE1 and WE2 which modified with g-C3N4-Ag NPs and Ru-MOF-Ag NPs to etch Ag NPs of the luminescences and further change the size.On the WE1,the energy transfer efficiency between g-C3N4 and Ag NPs was reduced and the ECL intensity was increased.While the ECL intensity on WE2 was decreased because the the electron transfer rate was reduceed.To study the performance of the platform,MyO was selected as the object.With the increasesing of MyO,the concentration of H2O2 was increased,and size of Ag NPs is smaller on interface.So,the efficient of RET and electron transfer rate were decreased,and different signals from the WE1 and WE2 were obtained.Finally,MyO was detected accurately and sensitively by their ratio from WE1 and WE2,the linear range is 1.0×10-13–1.0×10-6 g/m L and the detection limit as low as 4.7×10-14 g/m L.This sensing platform also shows excellent performance in serums detection and providing a new method for the detection of cancer markers. |
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