| Malignant tumor is a serious hazard to human health.The presence or quantitative change of tumor markers in human body could indicate the change of tumor properties,which could be used to assist in the diagnosis,classification,prognosis judgment and treatment guidance of tumor.Therefore,it has great significance for sensitive and accurate detection of tumor markers.Electrochemiluminescence?ECL?has been developed rapidly in recent years due to its advantages of high sensitivity,wide linear range,great selectivity and so on.Besides,in ECL field,multiple luminescent signals could be detected simultaneously at the same or different electrode interface based on the excitation potential interval of different light emitter.In the paper,combining ECL detection with ratiometric method,microfabrication technology and so on,a series of new ECL sensing platform were assembled for highly sensitive and accurate detection of tumor markers based on the excellent luminescent properties of luminescent nanomaterials and the specific recognition of aptamers or antibodies.In addition,the practical application of biochemical analysis was also carried out.The main innovations and research contents are as follows.1.A label-free ECL sensing platform was designed for carcinoembryonic antigen?CEA?sensitive detection using ZnS-CdS NPs as luminescent nanomaterials,aptamers as recognition elements on MoS2 NPs modified glassy carbon electrode?GCE?.Layered-MoS2 NPs with a large surface area were prepared by a sample hydrothermal method and used as an electrode matrix for subsequent electrodeposition of ZnS-CdS NPs.The results indicating the ZnS-CdS NPs decorated MoS2 electrode shows a higher ECL intensity.For the fabrication of the aptasensor,chitosan was coated on the ZnS-CdS/MoS2/GCE for CEA aptamer immobilization through covalent coupling method.The prepared ECL aptasensor for CEA detection exhibits a linear range from0.0500 to 20.0 ng/m L with a low detection limit of 0.031 ng/m L.Moreover,the method was successfully applied for CEA determination in human serums and the results were consistent with those of Xinyang Central Hospital.The recoveries of standard addition ranged from 80.0%to 111%.2.A dual-signal-output self-calibrated ratiometric assay platform was developed based on CdS-C NFs and luminol-Au NPs nanomaterials,aptamer as recognition element and ECL-RET between luminescent nanomaterials for sensitive and accurate detection of CEA.CdS-C NFs and luminol-Au NPs have excellent luminescence properties and could emit ECL signals at cathode and anode respectively.Based on the overlap between ECL emission spectrum of CdS-C NFs and absorption spectrum of Au NPs and catalysis of Au NPs,the signal quenching of CdS-C NFs and the signal enhancement of luminol could be induced in one potential scan.With this novel ECL-RET strategy,the ratiometric ECL aptasensor self-calibrated by the ratio of anodic ECL signal from luminol-Au NPs to the cathodic ECL signal from CdS-C NFs exhibits excellent analytical performance for CEA with a range of 0.100 pg/m L–10.0ng/m L and a detection limit of 0.033 pg/m L.In addition,the obtained ratiometric sensing platform was employed to quantify the CEA concent in human serum samples,the results comparable to the reference value provided by Xinyang Central Hospital and the recoveries range from 90.0%to 110%.3.A spatial-resolved dual-signal-output ECL ratiometric assay platform was constructedbasedonthree-dimensional?3D?flower-likeCdSand Ru?bpy?32+-conjugated silica nanoparticles(Ru?bpy?32+@RuSi NPs)as cathodic and anodic luminescent nanomaterials on a dual-disk GCE for sensitive detection of prostate specific antigen?PSA?.First,3D flower-like CdS and Ru?bpy?32+@RuSi NPs were immobilized onto the two disks?disk I and disk II?,respectively.After the stepwise modification of the gold nanoparticles,antibody for PSA,and bovine serum albumin onto the two disks respectively,the Ru?bpy?32+@RuSi NPs-based disk was incubated with varied concentration of PSA as working electrode,whereas the 3D flower-like CdS-based disk with fixed concentration of PSA were taken as internal reference electrode.The assay of PSA was realized by the ratio of anodic ECL signal from working electrode to the cathodic ECL signal from the internal reference electrode(ECLanode/ECLcathode).On the basis of the spatial-resolved dual-signal-output ratiometric ECL sensor,the PSA can be detected accurately with a linear range of 1.00pg/m L–50.0 ng/mL at a concentration as low as 0.34 pg/m L.Furthermore,the proposed method was applied for PSA determination in human serum samples,the results comparable to the reference value provided by Xinyang Central Hospital and the recoveries range from 80.0%to 104%.The same biometric identification process of the two disks well avoids the interference caused in environmental change,biological recognition process and so on,which effectively reduces the false positive or negative errors.4.Using microfabrication technology,a simple BPEs-ECL imaging platform was fabricated based on functional nanoprobes of Ru?bpy?32+@SiO2/Au nanoparticles on a closed bipolar electrode?BPE?for visual immunoassay of PSA in human serum samples and the surface of single cancer cells?LNCaP cells?for the first time.Multiple-assisted ECL signal amplification strategy was introduced into the detection system on the basis of the synergetic amplifying effect of the anodic and cathodic amplification.Based on the synergetic amplifying effect,the versatile ECL platform allowed for the detection of PSA with a detection limit of 3.0 pg/m L using photomultiplier as detector and 31 pg/m L?S/N=3?by CCD camera imaging.The obtained immunosensor was employed to evaluate PSA levels in serum samples,the results comparable to the reference value provided by Xinyang Central Hospital and the recoveries range from 80.0%to 108%.Moreover,the obtained functional nanoprobes were used to achieve the ECL imaging of single LNCaP cells based on a bare BPE.The results showed that the functional nanoprobes-based ECL imaging immunoassay provides a promising visual platform for detecting tumor markers?proteins and cancer cells?,and thus shows a highly potential prospect. |
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