Polyacrylamide-incorporated copper electrodes for electrochemical-colorimetric dual-mode detection of H2O2 released from tomato leaves

Hydrogen peroxide (H2O2) plays a key role in a diverse array of cellular signaling pathways, which is closely related to plant health and physiological status. The accurate and efficient monitoring of H2O2 in living plant cells has attracted enormous interest. Herein, we developed an electrochemical-colorimetric dual-mode sensor based on the peroxidase-like activity of a polyacrylamide (PAM) -modified copper electrode (Cu-PAM), allowing for the in situ detection of H2O2 released from tomato leaves. The co-electrodeposition of unique combination of Cu and polyacrylamide, as well as the active site structure of Cu-centered peroxidases, can enhance adsorption performance by the hydrogen bonds between PAM with H2O2, which exhibited excellent electrochemical performance with a low limit of detection (LOD) of 0.0167 mM and a detection range of 0.05-25.31 mM. Meanwhile, a colorimetric signal output of the sensor that can be quantified from 1 mu M to 70 mu M with a LOD value of 0.33 mu M. This work demonstrates a huge potential application prospect of the polyacrylamide-modified copper in the field of biosensors.