The Application Of ECLIAs Based On New Strategies Of Signal Amplification In Food And Environmental Safety

With the growth of people's living standards,"health" has become the focus of people's pursuit,and food and environmental safety issues have attracted more and more attention.In order to detect trace contaminants in food and environment simply and quickly,it is imperative to develop a highly sensitive analytical method.Electrochemiluminescence(ECL)immunosensor is a fast and sensitive biosensor which combines ECL with immunoassay technology.In order to improve the sensitivity of analysis,signal amplification technology has been applied to the construction of sensors.Because of their unique optical,electrical and catalytic properties,nanomaterials can not only be used as carriers for biochemical reactions and signal aggregation,but also as mimetic enzymes for catalytic reactions to increase the electron transfer rate and the load of signal molecules.Therefore,in recent years,ECLIAs based on signal amplification strategy of nanomaterials has become a major research hotspot in the field of analysis and detection.In this paper,PEDOT:PSS functionalized graphene oxide(GO/PEDOT),Au nanorods(AuNRs),Pd/Pt core-shell nanocrystallines(Pd/Au CSNs),gold nanorods functionalized graphene oxide nanocomposite film(GNRs/GO),Pt/Pd nanodendrites(Pt/Pd NDs)and other nanomaterials were synthesized and applied to the sensor construction.Based on the modification of functionalized nanomaterials,a series of new strategies for signal amplification have been developed,which provide effective analytical methods for the research of food and environmental safety.The paper mainly includes the following parts:1)A novel ECL immunosensor for detecting DCF was constructed using GO/PEDOT connected quantum dots(QDs-PEI-GO/PEDOT)as signal amplification carrier.The electrode was modified with AuNRs which increase the load capacity of DCF coating antigen through Au-N bond.The prepared anti-DCF polyclonal antibody(pAb)has high affinity for DCF recognition,which greatly improves the sensitivity and selectivity of the sensor.Consequently,the immunosensor has been successfully applied to the detection of actual water samples with a low detection limit(LODs)of 0.33 pg mL-1(S/N=3).2)A novel ultrasensitive competitive-type ECL immunosensor for detecting Sudan I was constructed using Pd/Au CSNs as signal bioprobe.The surface of electrode was coated with GNRs/GO as the substrate,which could immobilize more coating antigen but also facilitated the electronic transmission to increase the ECL signal.The proposed immunoassay based on the synergistic effect of Pd/Au CSNs and GNRs/GO for determining Sudan I exhibited good stability,high sensitivity and wide linearity with a LOD of 0.3 pg mL-1(S/N=3),and was successfully applied in determination of real samples with acceptable accuracy.3)A competitive-type ECL strategy for Hg2+determination based on peroxydisulfate/oxygen(S2O82-/O2)system was structured by using Pt/Pd NDs-thiosemicarbazide/norfloxacin(TN)covered gold nanoparticles(Pt/Pd-TNGso)as signal enhancer.The binary-intramolecular synergistic catalysis of Pt/Pd-TNGso could extremely enhance the ECL signal of the S2O82-/O2 system.As a result,the proposed immunosensor displayed high sensitivity and stability,and was gratified in Hg2+detection with a LOD of 16 pg mL-1(S/N=3).