Three CdSmaterialswithdifferentshapes(i.e.,irregular,rod-like,andelongatedhexagonal-pyramid)
werehydrothermallysynthesizedthroughcontrollingthemolarratioofCd2þ to thiourea.Electro-
chemical experimentsshowedthattheelongatedhexagonal-pyramidCdS(eh-CdS)modified onglassy
carbon electrode(GCE)hadthehigherelectricalconductivitythantheothertwoforms.Thentheeh-CdS
modified GCEwasfurthermodified withalayerofpoly-isonicotinicacid(PIA)throughelectro-
polymerization inIAsolutiontoenhancethestabilityandfunctionalityoftheinterface.Thelayer-
by-layermodification processwascharacterizedbyatomicforcemicroscopyandelectrochemistry.Then
50-amino functionalizedDNAwasimmobilizedontheelectrodesurfacethroughcouplingwiththe
carboxylicgroupsderivedfromPIA-eh-CdScomposite film. Thehybridizationperformanceofthe
developed biosensorwasevaluatedusingmethyleneblueasredoxindicator,andtheresultsshowedthat
the peakcurrentsofmethylenebluevariedwithtargetconcentrationsinawidelinearrangefrom
1.01014M to1.0109 M withalowdetectionlimitof3.91015 M. Thebiosensoralsoshowed
high stabilityandgooddiscriminationabilitytotheone-base,three-basemismatchedandnon-
complementary sequence.