Blade-style molecularly imprinted polymers (MIPs) electrochemical sensors for in vivo analysis of trace indole-3-acetic acid (IAA) in tomato fruits and leaves

Electrochemical sensors based on molecularly imprinted polymer (MIP) provide an exceptional platform for sensitive and selective analysis of analytes in complex matrix through incubation while in vivo analysis is critical for achieving quantitative information for the biological study in real time. However, the deployment of MIP electrochemical sensors for in vivo analysis highly depends on their forms and fabrication. Here blade-style MIP electrochemical sensors were designed and fabricated in batches based on the technique of lamination, focusing on their applications for in vivo analysis of trace indole-3-acetic acid (IAA) in plants. The blade-style electrochemical sensors were fabricated using stainless steel sheets as supporting and conductive substrates for the working electrodes. The MIP sensors were prepared in batches using cyclic voltammetry (CV) based electropolymerization of pyrrole (the functional monomer) and IAA (the template) followed by elution under a constant potential at a multichannel electrochemical station with improved throughput. After optimization, the sensors could stably and reproducibly quantify IAA with the detection limit of 0.1 μmol·L −1 . The blade-style MIP sensors could be either plugged in tomato fruits for in vivo analysis of IAA or coupled with a piece of hydrogel for non-invasive analysis of IAA in tomato leaves. The blade-style MIP electrochemical sensors may provide a platform for in vivo analysis by not only obviating the time-consuming sample treatment but also simplifying the analytical procedure. This study may pave the way for extensive applications of MIP electrochemical sensors for real-time, spatially resolved analysis of endogenous biomolecules in living organisms in the near future.