▎ 摘　　要

NOVELTY - The device has a conductive unit placed on a substrate (1) and including two electrodes (21). A sensing layer (3) is placed on the conductive unit and electrically connected with the electrodes. The sensing layer includes polyethyleneimine and polyethylene glycol and absorbs carbon dioxide. An insulating layer (4) is placed on the electrodes. The conductive unit includes a conductive element (22) that is electrically connected to the electrodes and the sensing layer, where the electrodes are selected as carbon electrodes, weight ratio of polyethyleneimine to polyethylene glycol ranges from 1:0.03 to 1:1, and the polyethyleneimine is selected as branched polyethyleneimine. USE - Gas sensing device for diagnosing chronic obstructive pulmonary disease (COPD) in clinical practice. ADVANTAGE - The gas sensing device comprises the substrate, the conductive unit, and the sensing layer, where the sensing layer is placed on the substrate, and the sensing layer is electrically connected with the electrodes, so as to reduce gas detection error. The device enhances detection response of polyethylenimine to carbon dioxide by addition of polyethylene glycol, so that the sensing layer can exhibit detection sensitivity to carbon dioxide. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a system for detecting change of electrical property of a gas sensing device. DESCRIPTION OF DRAWING(S) - The drawing shows a top perspective view of a gas sensing device. Substrate (1) Sensing layer (3) Insulating layer (4) Electrodes (21) Conductive element (22)