Plant Sensor Based On Au@SnO₂-vertical Graphene Microelectrode

Abscisic acid(ABA)is an inhibitory plant hormone that not only inhibits the synthesis of deoxyribonucleic acid and protein,but also promotes the ripening of fruits and the shedding of leaves.It plays an important role in the growth of plants.Understanding the dynamic changes of abscisic acid levels during plant growth is of great significance for studying how abscisic acid regulates and controls plant growth and development.Therefore,it is necessary to detect the content of abscisic acid in plant tissues.This paper studies an electrochemical sensor based on core-shell Au@SnO₂-vertical graphene(VG)microelectrodes to detect the content of abscisic acid in plants.First,use magnetron sputtering physical vapor deposition equipment to grow a layer of tin oxide(SnO₂)on the tantalum wire;then attach tetrachloroauric acid on the SnO₂by immersion method;finally use DC arc plasma sputtering chemical vapor deposition equipment Grow graphene to construct core-shell Au@SnO₂-VG microelectrodes.Scanning electron microscopy,transmission electron microscopy,Raman spectroscopy,X-ray powder diffraction,X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy were used to study the morphology,microstructure and composition of the Au@SnO₂-VG layer.Three Au@SnO₂-VG microelectrodes were prepared as working electrodes,and platinum wires and titanium wires were used as counter electrodes and reference electrodes,respectively,to form a microelectrode array sensor for electrochemical detection of ABA.The study of the ABA response mechanism shows that the microelectrode array sensor cooperates with the abundant adsorption sites of Au@SnO₂nanoparticles and the excellent conductivity of VG in response to ABA.The Au@SnO₂-VG microelectrode sensor quantitatively detects ABA with a p H range of 4.0?7.0 and a response concentration range of 0.012?495.2?M.It has high sensitivity(0.02?0.07?A·?M^-1)and low detection limit(0.01?1.33?M),and a long life span of one month.In addition,the establishment of an ABA quantitative detection model in a wide p H range meets the need for large differences in plant p H when testing physical objects.The Au@SnO₂-VG microelectrode array sensor,for the first time,quantitatively responds to ABA concentration through an enzyme-free and non-immune electrochemical method,and is suitable for in-situ detection of ABA in plant tissues.The design ideas and detection strategies of this reliable,stable and convenient microelectrode array sensor have considerable application potential in the in-situ detection of plants'small molecules.