SnS<sub>2</sub> QDs@MXene Ohmic Junction-Based Surface\nPlasmon Coupling ECL Sensor to Detect Saliva Exosome for the Diagnosis\nof Childhood Asthma

This study represents a novel surface plasmon coupling\nelectrochemiluminescence\n(SPC-ECL) method for detecting salivary exosomes and the diagnosis\nof childhood asthma. First, SnS<sub>2</sub> QDs@MXene Ohmic junctions\nwas developed as efficient ECL emitters. The Ohmic junction provided\na low resistance to reduce the contact resistance and improve charge\ninjection efficiency, which enhanced the ECL signal by 2.76 times.\nFurthermore, the self-assembled surface plasmonic Bi@SiO<sub>2</sub> array was prepared. When the ECL of SnS<sub>2</sub> QDs@MXene resonated\nwith the electronic oscillations in the Bi@SiO<sub>2</sub> NPs array,\nthe luminescence intensity was enhanced and regulated into the directionally\npolarized signal by the SPC-ECL effect. Remarkably, the detection\nof CD9-exosomes in saliva was achieved successfully based on the above\nsensing system, which can be used to analysis the acute exacerbation\nand chronic persistence of childhood asthma.