| Porcine epidemic diarrhea virus（PEDV）is a highly contagious coronavirus that causes severe diarrhea and death in neonatal piglets,which seriously affects the safety of food raw materials.It is important to develop analytical methods to ensure food safety.Therefore,it is extremely important and necessary to establish a simple,fast,and accurate method for detecting PEDV.Electrochemiluminescence is a powerful analytical technique that combines electrochemistry and spectroscopy,which can be used for trace amount of target detection.At present,the main problems of ECL methods are as follows:Firstly,the ECL signal is weak and it is difficult to achieve the required sensitivity;Secondly,some coreactive agent systems,such as tri-n-propylamine,are toxic,volatile and corrosive;Thirdly,traditional ECL materials have poor signal stability and high background in applications.In this paper,PEDV and antibody detection methods are developed according to the above research background,combined with signal amplification mehods,coreactant,synthesis of new materials,and different signal output modes.The details are as follows:1.Versatile Electrochemiluminescence Assays for PEDV Antibody Based on Rolling Circle Amplification and Ru-DNA NanotagsUltra-sensitive detection of low abundance protein is important for early diagnosis of various animal diseases.In order to obtain satisfactory results,a new multiple pathways signal amplification method was proposed to construct a sensitive ECL platform for the detection of PEDV antibody.Using antibody-antigen reaction as the recognition unit,Au NP modified graphene nanosheet（Au-GN）as the substrate,rolling circle amplification（RCA）for signal enhancement,and assembled cascade Ru-DNA nanotags as signal label,the sensitive detection method of PEDV antibodies had been achieved.The proposed ECL sensor exhibited good analytical performance for PEDV antibody with a wide linear range from 0.1 pg/m L to 5 ng/m L with a detection limit of 0.05 pg/m L（S/N=3）.The proposed strategy exhibited the advantages of excellent stability and sensitivity for determination of the PEDV antibody,which was successfully used in the quantitative analysis of PEDV antibodies in serum.2.Electrochemiluminescence of Porphyrinic Zirconium Metal-organic Framework PCN-224 in Aqueous Media.PCN-224 has porous cube structure,large specific surface area and stablephotochemical properties,which is a Zr（IV）-based MOF constructed with meso-tetrakis（4-carboxyphenyl）porphyrin.The investigation of mechanisms for ECL of PCN-224 both in annihilation and coreactant was reported.According to the results,the weak ECL emission of PCN-224 was produced in the annihilation route.Highly efficient ECL signal was observed in the cathodic region upon addition of potassium peroxodisulfate as the coreactant.The ECL quantum efficiency of PCN-224 in 0.05mol/L K2S2O8 system was calculated to be 6.8%.This study not only enriched the basic research on the ECL performance of PCN-224,but also opened up the possibility of using PCN-224 composite materials to construct ECL biosensors.3.High-Sensitivity Electrochemiluminescence Probe with TiO2 Sensitized PCN-224for PEDV SensingA sensitive ECL biosensor was developed for PEDV detection based on a novel PCN-224/K2S2O8/TiO2 ternary ECL system with TiO2 sensitized PCN-224 as signal label for signal amplification.Specifically,TiO2 nanoparticles were used as the coreaction accelerator for the first time to promote the reduction process of coreactant potassium peroxodisulfate in the cathode and significantly increased the ECL signal of PCN-224 for an amplified initial signal.As a result,the novel“signal off”biosensor achieved a sensitive detection of PEDV range from 1 pg/m L to 10 ng/m L with a detection limit of0.4 pg/m L（S/N=3）.Importantly,the proposed strategy enriched the application of PCN-224 and potassium peroxodisulfate ECL system in bioanalytical applications,and provided a new strategy in signal amplification4.A Highly Sensitive Ratiometric ECL Biosensor for PEDV Detection Based on PCN-224 and Pt/Au HNRs-Catalyzed LuminolAn ECL biosensor was designed for the determination of PEDV using a novel ECL resonance energy transfer（ECL-RET）strategy.In this strategy,luminol was acted as an ECL energy donor,while PCN-224,as a novel luminescent reagent,had been proved to be an effective and stable ECL receptor.In potassium persulfate solution saturated with oxygen,luminol could generate strong ECL signal using coreactive agent O2,and Pt/Au HNRs used its catalytic effect to amplify its ECL signal.At the same time,luminol’s ECL signal was quenched by the signal generated by PCN-224 using potassium persulfate as a coreactive agent.The luminol ECL signal gradually decreased with the increasing concentration of PEDV.The biosensor achieved a ratiometry detection of PEDV with a wide linear range from 0.01 pg/m L to 10 ng/m L.The detection limit was low to 3 fg/m L（S/N=3）.Luminol and PCN-224 as a new donor-receptor pair in ECL-RET system exhibited a great potential in the application of ECL biological analysis. |
