Electrochemically-assisted deposition of toluidine blue-functionalized metal-organic framework films for electrochemical immunosensing of Indole-3-acetic acid

A simple and rapid electrochemical synthesis strategy for in-situ fabrication of toluidine blue (TB)-functionalized metal organic framework ([email protected]) thin films via one-step reduction approach was reported. The [email protected] thin layer has been synthesized on the working electrode surface in different times at room temperature, and its morphology and thickness was characterized by varied instruments, including scanning electron microscope, transmission electron microscope, and scanning ion conductance microscope. The prepared [email protected] shows exceptional electrochemical activity and stability under mild conditions, and its electrochemical response is dependent on the amount of TB molecules which are encapsulated in the MOFs. Based on the [email protected] sensing platform, a sensitive label-free electrochemical immunosensor for the detection of Indole-3-acetic acid (IAA, a plant hormone) was developed with a wide linear range (2.5 pg mL−1 - 5 ng mL−1) and a low detection limit (1.4 pg mL−1). Moreover, this immune sensor shows good sensitivity and selectivity in real samples for IAA detection.