Despite the decline in incidence and mortality rates, gastric cancer (GC) is the fifth leading cause of cancer deaths worldwide. The incidence and mortality of GC are exceptionally high in Asia due to high H. pylori infection, dietary habits, smoking behaviors, and heavy alcohol consumption. In Asia, males are more susceptible to developing GC than females. Variations in H. pylori strains and prevalence rates may contribute to the differences in incidence and mortality rates across Asian countries. Large-scale H. pylori eradication was one of the effective ways to reduce GC incidences. Treatment methods and clinical trials have evolved, but the 5-year survival rate of advanced GC is still low. Efforts should be put towards large-scale screening and early diagnosis, precision medicine, and deep mechanism studies on the interplay of GC cells and microenvironments for dealing with peritoneal metastasis and prolonging patients’ survival.

Metal oxide and its hybridized gas sensor materials with noble metals, graphene, and conducting polymers have proved their advantageous performance, such as high sensitivity, low working temperature, and fast carrier transportation properties. However, oxide semiconductor materials have low carrier mobility and tend to have a high impedance in sensor devices. Herein, we demonstrate a molecular gas sensor with a switching charge carrier, using a noble hybrid graphene–semiconductor and a three-dimensional (3D) metal-oxide MoO x nanorod network. A hybrid gas sensor has an extremely low impedance owing to the replacement of the conduction seed layer with graphene. The device achieved carrier-type switching with a high-speed response to gas molecules based on a fine 3D MoO x nanorod network. The device showed a low impedance of 10–2 Ω and a high speed response/recovery time of about 20–30 s at 400 ppm EtOH gas concentration. This study proves the feasibility of separate control of chemical and physical mechanisms in the gas sensing device owing to the combination of the large surface area of the fine 3D nanostructure and high mobility of graphene. Based on the results of this study, the basic design of semiconductor gas sensors will reconstruct, and it can be separated by the parts of carrier conduction and the catch/release block of gas molecules.

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