An ultrasensitiveaptasensorwasfabricatedasanelectrochemicalnanotoolbasedontheconformation switching ofanaptamer(Apt).TheAptwhichwascovalentlyattachedonthesurfaceofaglassycarbon electrode (GCE)coveredwithcadmiumtelluride(CdTe)quantumdots(QDs)worksasauniquemodifier for assayingcocaine.TheAptwascombinedwithcocainetoformathree-wayjunctioncomplex;this complexincreasedthesterichindranceofthemodified GCEsurfaceandresultedinavariationofthe corresponding currentofaredoxprobe.Inthepresentstudy,DPVtechniqueforcocainedetectionwas applied andresultedinanunprecedenteddetectionlimit(LOD)of5.070.1pmolL1, whichismore sensitivethanpreviouslyreportedmethods.Oneofthegreatestadvantagesofthisaptasensoristhe elimination ofenzymesorantibodies.Itisalsorelativelyahighlysensitive,simple,reproducible,and controllable nanotool.Likewise,itcanbeeasilyminiaturized,whichisanecessaryconditionforthehigh- throughput systemandon-siteapplications.Theofferednanotoolhasagreatpromisefortheroutine analysisoftheultra-traceamountsofcocaine,whichisimportantforlawenforcementandclinical medicine. Itisnotabletosaythatfurtherattemptsareunderwayinourlaboratoryfortheconstructionof other aptasensorswithhigherperformanceforspecific targetssuchasthedetectionofmethadone (MTD) andibuprofen(IBP).
