Researchers from Brazil's UNICAMP and University of São Paulo have developed a wearable plant sensor fabricated on a paper substrate using the laser-scribed graphene (LSG) technique to detect paraquat (PQ) in crops.
A synergistic effect was observed due to the combination of colorless nail polish and the chemically treated paper substrate, resulting in high-performance, conductive carbon-based graphene tracks attributed to the porous nature of the electrode fabrication process. The device detects PQ by square wave voltammetry (SWV) at concentrations ranging from 0.5 to 100.0 μmol L-1 in a 0.1 mol L-1 Britton-Robinson (BR) buffer (pH 9.0), with a limit of detection (LOD) of 0.082 μmol L-1.
The wearable plant sensor demonstrated excellent mechanical durability under repeated bending cycles, simulating real-world conditions on crops.
Furthermore, it showed remarkable selectivity in the presence of commonly used pesticides and molecules typically found in natural beverage samples derived from fruits.
As proof of applicability, the flexible and sustainable non-enzymatic wearable sensor was applied directly to the surfaces of fruits and leaves to detect PQ using a portable potentiostat and a smartphone. The results confirmed its suitability for on-site pesticide detection, making it an effective tool for precision agriculture (PA) applications.
