Study On The Construction Of Electrochemical Aptasensors Based On Multiple Strategies For Zearalenone Detection

Zearalenone?ZEN?,one of the nonsteroidal estrogenic mycotoxin,called as F-2 toxin,is a secondary metabolite of Fusarium fungi.Various crops are susceptible to Fusarium fungi contamination in all aspects of growth,harvest,storage,and transportation.ZEN could be detected in crops,feeds,and related agricultural and sideline products,because it is difficult to destroy the mycotoxins.Once the mycotoxin entered the food chain,they would severely threaten the health of animals and humans.In most countries and regions,there are different regulations of maximum residue levels for ZEN along with the increasing concern of food safety.Therefore,in this paper,two different electrochemical aptasensors were designed based on nanomaterials and target-induced signal amplification strategies for the ZEN detection.The foremost research contents of this theme are as follows:Part?An electrochemical aptasensor for highly sensitive detection of zearalenone based on PEI-MoS₂-MWCNTs nanocomposite for signalenhancementObjective:To construct an electrochemical aptasensor with a high signal response for ZEN detection based on nanomaterial.Method:Firstly,the polyethyleneimine?PEI?functionalized molybdenum disulfide?MoS₂?doped multi-wall carbon nanotube?PEI-MoS₂-MWCNTs?nanocomposite was prepared and used as a sensing platform,the bioactive molecule of toluidine blue?Tb?as the signal probe.Then,Pt@Au nanoparticles were dropped on the modified electrode to support a large amount of thiol-modified ZEN binding aptamer?ZBA?.The variation of the electrochemical signal response,which originated from Tb was measured by CV after ZEN binding to ZBA with high affinity.Result:The aptasenor had an excellent linearity in the range from 0.5 pg mL^-11 to 50 ng mL^-1?R=0.9918?,with the LOD of 0.17 pg mL^-1.The recovery rate in beer samples was 85.32%¹00.2%.Conclusion:The construction method of this aptasensor is easy and fast,which has good selectivity and stability.Part?A signal-on amperometic aptasensor for sensitive zearalenone detection by CS@AB-MWCNTs nanocomposite and carboxylatedgraphene oxide as enhancersObjective:To construct a novel signal-on aptasensor for highly sensitive detection of ZEN based on target-induced amplification strategy.Method:The chitosan?CS?functionalized acetylene black?AB?and multi-walled carbon nanotubes?MWCNTs?nanocomposite?CS@AB-MWCNTs?was synthetised and served as the sensing platform.In addition,carboxylated graphene oxide-labeled ZEN binding aptamer?CGO-ZBA?was applied to enhance the intensity of signal change.In the presence of ZEN,CGO-ZBA would specifically recognized with ZEN,allowing the electrochemical signal of[Fe?CN?₆]^3-/4-increased with CGO-ZBA detaching from the modified electrode.DPV was employed to record signal changes before and after the binding of ZEN with different concentrations.Result:The aptasensor for ZEN with a linear range from10 fg mL^-11 to 1 ng mL^-1?R=0.9939?and a low LOD of 3.64 fg mL^-1,had good selectivity and stability.The recovery varied in beer sample was85.11%¹02.0%.The intra-assay RSD and the inter-assay RSD were7.66%and 2.40%,separately.Conclusion:This aptasensor overcome the problem of false positives based on target-induced strategy,which has good reproducibility,selectivity and stability.