An impedance biosensor is reported that employs the bidentate thiol, 16-[3,5-bis(mercaptomethyl)phenoxy]-hexadecanoic acid (BMPHA), as a bifunctional reagent for antibody immobilization atop an Au electrode, and the results are compared to those obtained for the analogous monodentate reagent, 16-mercaptohexadecanoic acid (16 MHA). The detection limit for peanut protein Ara h 1 on the BMPHA bidentate thiol- coated Au electrode is approximately 0.71 ng/mL (0.01 nM), about 3x lower than that obtained on the comparable monodentate (16-MHA) thiol-coated Au electrode. Daily impedance measurements were employed to study antibody regeneration with a mild denaturing agent, 0.2 M KSCN at pH 7.3. The antibody-coated electrodes retained activity towards Ara h1 for 10 and 20 days of regeneration of the monodentate- and BMPHA-coated Au electrodes, respectively, illustrating the superior stability of protein films atop the BMPHA bidentate thiol.
Radhakrishnan, Rajeswaran, Pali, Madhavi, Lee, Han J., Lee, Thomas R. and Suni, Ian. "Impedance Biosensor Incorporating a Carboxylate-Terminated Bidentate Thiol for Antibody Immobilization." Journal of the Electrochemical Society 163, No. 5 (Jan 2016): B125-B130. doi:10.1149/2.0301605jes.