Smart wearable flexible sensor based on laser-induced graphene/gold nanoparticles/black phosphorus nanosheets for in situ quercetin detection

In situ detection of metabolic substances in plants is necessary for the development of smart agriculture. However, there is a mechanical mismatch between the traditional rigid sensing interfaces and the softness surface of plant leaves, which can reduce the reliability and accuracy of sensor. Stretchable and flexible sensors provide new solutions to this problem. Herein, using quercetin (Que) as a model, we developed a flexible electrochemical sensor for in situ monitoring of metabolite in plants. A light and thin laser-induced graphene (LIG) electrodes with good flexibility were obtained after polydimethylsiloxane (PDMS) transfer. Gold nanoparticles (AuNPs) and two-dimensional black phosphorus (BP) nanosheets were fabricated on the electrode to further improve the electrochemical performance. The sensor can detect Que concentrations in the range of 1-100 mu M with a detection limit of 0.65 mu M (S/N=3). The sensor can adapt well to the soft plant leaf surfaces, thus realizing the application of in situ and in vivo detection in the field. This innovative plant wearable biosensor is expected to be a next-generation electronic candidate for intelligent agriculture, paving the way for in-situ and in vivo detection, and facilitating the intelligentsias of modern agriculture.