Practical application of wearable gas-sensing devices has been greatly inhibited by the poorly sensitive and specific recognition of target gases. Rapid charge transfer caused by rich sensory neurons in the biological olfactory system has inspired the construction of a highly sensitive sensor network with abundant defect sites for adsorption. Herein, for the first time, we demonstrate an in situ formed neuron-mimic gas sensor in a single gas-sensing channel, which is derived from lattice deviation of S atoms in Bi 2 S 3 nanosheets induced by gold quantum dots. Due to the favorable gas adsorption and charge transfer properties arising from S vacancies, the fabricated sensor exhibits a significantly enhanced response value of 5.6-5 ppm NO 2 , ultrafast response/recovery performance (18 and 338 s), and excellent selectivity. Furthermore, real-time visual detection of target gases has been accomplished by integrating the flexible sensor into a wearable device.