An impedance immunosensor for the detection of the phytohormone abscisic acid.
The phytohormone abscisic acid (ABA) is the major player in mediating the adaptation of plants to stress. Previously developed phytohormonal biosensors usually employed indirect detection of the products of conjugated oxidase reactions. A label-free electrochemical impedance immunosensor for ABA detection was developed using an anti-ABA antibody adsorbed directly on a porous nanogold film. The film was produced electrochemically on a glassy carbon electrode in 0.008 mol/L hydrogen tetrachloroaurate solution containing 0.004 mol/L lead acetate with an applied potential of -0.5 V (versus Ag/AgCl) for 50 s. The anti-ABA antibody was immobilized onto the porous nanogold through electrostatic adsorption and covalent conjugation. Electrochemical impedance spectroscopy was used to characterize the successful construction of the porous nanogold film and the stepwise modification of the glassy carbon electrode. The concentration increase of the antigen brought about a decrease of the interfacial electron transfer, which also meant an increase of the impedance signal. The experimental parameters pH, antibody incubation time, and antibody concentration were optimized. The results showed significant linearity R = 0.9942, with the content of ABA in the range 0.5-5,000 ng/mL with a detection limit at about 0.1 ng/mL.
Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Furong District, Changsha Hunan, 410128, China.
Yu-Wei
YW
Li
Kai
K
Xia
Ruo-Zhong
RZ
Wang
Jian-Hui
JH
Jiang
Lang-Tao
LT
Xiao
D000040:Abscisic Acid / Q000032:analysis* / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002244:Carbon / Q000737:chemistry; D004563:Electrochemistry; D004566:Electrodes; D005898:Glass / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D007118:Immunoassay / Q000379:methods*; D049329:Nanostructures / Q000737:chemistry; D010937:Plant Growth Regulators / Q000032:analysis* / Q000737:chemistry; D013499:Surface Properties
D010937:Plant Growth Regulators; D000040:Abscisic Acid; D002244:Carbon; D006046:Gold