Construction Of IAA Biosensors Based On IAA Receptor And Antibody

β-indole acetic acid(IAA)is a ubiquitous plant hormone in plants and plays an important role in the growth and development of plants.Therefore,it is great significance of establishing a simple,rapid and accurate IAA detection method.In current existed detection methods,the electrochemical method has been acclaimed as a result of its excellent performance of high sensitivity and dynamic monitoring.In this reserch,gold nanoparticles modified electrode was electrodeposited and immobilized with monoclonal antibody/TIR1(Transport Inhibitor Response 1)protein on the surface of modified electrode to construct a biosensor electrode with affinity and adsorption ability for IAA.The main results were summarized as follows:1.Gold nanoparticles were modified to the electrode surface by electrochemical deposition,which improved the conductivity of the electrode and enabled it to adsorb proteins.It was found that the best modification condition of the electrode was the deposition of-0.2 V potentiostatic potential of 90 s in the solution of chloroauric acid with a concentration of 20 mM.An immune sensor based on IAA monoclonal antibody was constructed.The binding of IAA and immobilized antibody on the electrode was detected by electrochemical detection.The linear response range was 1-500 ng/m L,and the detection limit was 0.1 ng/m L.2.The biosensor of IAA was also constructed under the same electrode modification condition.The TIR1 protein can be adsorbed to the electrode surface,and the non-adsorbed sites on the electrode surface were filled with bovine serum protein.The constructed electrode can compatibly adsorb the IAA and form TIR1-IAA complex,resulting in the decrease of electron transfer rate on the electrode surface.At this point,the current peak on the surface of the working electrode decreases.In addition,in a certain range of IAA concentration,the current peak and IAA concentration had positive linear relationship.In this study,we also optimized the construction conditions of the sensor,including adsorption temperature,protein concentration and adsorption time.The results showed that the IAA biosensor based on IAA receptor was superior to the IAA immune sensor based on monoclonal antibody.The linear response range was from 0.5 ng/m L to 500 ng/mL with a detection limit of 0.01 ng/mL.