Molecularly Imprinted Electrochemical Aptasensor for the Attomolar Detection of Bisphenol A.
Ali A. Ensafi, Maryam Amini, Behzad Rezaei,
Gold nanoparticles (AuNPs) were electrodeposited on the surface of a glassy carbon electrode (GCE) and then treated with a mixture of a thiolated DNA
sequence (p-63; with high affinity for bisphenol A) and free bisphenol A (BPÀ). Pyrrole was then electropolymerizaed on the surface of the GCE to entrap the
BPA@p-63 complex. BPA is then extracted with acetic acid solution to obtain MIP cavities where the embedded DNA sequence acts as the binding site for
BPA. Scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry were employed to characterize the surface of the
modified GCE. Under the optimum conditions, the sensor has a dynamic range that covers the 0.5 fM to 5 pM BPA concentration range and an 80 aM detection
limit. The sensor was applied to the quantitation of BPA in (spiked) milk, milk powder and water samples and gave acceptable recoveries.