Voltammetric aptasensor for bisphenol A based on double signal amplification via gold-coated multiwalled carbon nanotubes and an ssDNA–dye complex

摘要: An aptasensor is described for the electrochemical determination of bisphenol A (BPA). Gold-coated multiwalled carbon nanotubes (Au/MWCNTs) and a single-stranded DNA-dye complex are used as double signal-amplification system. The BPA-binding aptamer was assembled on disposable electrode modified with Au/MWCNTs. Methylene blue (MB) then intercalated into immobilized an approximately molecular ratio 4 to form complex. Upon interaction BPA, underwent conformational change. This causes MB be released from solution. As result, signal MB, typically measured using square wave voltammetry at potential −0.20 V (vs. Ag/AgCl (saturated KCl)) decreases. fabrication characterized by scanning electron microscopy, atomic force techniques. Under optimal experimental conditions, current drops linearly logarithm BPA concentrations over range 10 fM 1 nM, limit detection 8 fM. assay applied in plastic drinking bottles, tap water, milk.