Dual-Mode electrochemical biosensors based on Chondroitin sulfate functionalized polypyrrole nanowires for ultrafast and ultratrace detection of acetamiprid pesticide

Chondroitin sulfate (CS) functionalized polypyrrole nanowires (PPyNWs) were prepared onto the glassy carbon electrode by constant potential method. A dual-mode electrochemical biosensor based on CS/PPyNWs for ultrafast and ultratrace detection of acetamiprid using the chronocoulometry (CC) and chronoamperometry (CA) methods. • CS/PPy nanowires was prepared by the electrodeposition method. • CS/PPy nanowires demonstrated showed excellent conductivity and high stability. • The dual-mode biosensor has been constructed using CC and CA methods. • The biosensor has shown excellent sensing performances. The inappropriate and excessive use of pesticides poses a great challenge to human health. It is necessary to analyze pesticide residues efficiently, economically and quickly to minimize the risk of public safety issues. Herein, a dual-mode biosensor was proposed for ultrafast and ultratrace detection of acetamiprid (ACE). The polypyrrole nanowires (PPyNWs) was prepared using the guidance of CS by electrochemical method, which showed large electroactive surface area, excellent conductivity and high stability. After immobilization of ACE aptamer onto CS/PPyNWs, the biosensor can be effortlessly prepared. The ACE concentration can be measured by both the signal decrease of the chronocoulometry (CC) method and the chronoamperometry (CA) method. The dual-mode biosensor exhibited ultrafast detection speeds of 0.5 s and 2 s across 9 and 6 orders of magnitude linear ranges through CC and CA, respectively. More importantly, the biosensor was successfully applied to detect ACE residues in soil samples, proving the feasibility of the dual-mode biosensor for ACE detection in complex samples.