Metal Oxide Semiconductor Gas Sensors for Exhaled Breath Cancer Biomarker Detection

Early cancer screening can significantly improve therapeutic outcomes, volatile organic compounds (VOCs) and other related gases in exhaled breath, as cancer-specific biomarkers, offer a novel approach for non-invasive diagnosis. Metal oxide semiconductor (MOS)-based gas sensors are pivotal for exhaled breath VOCs detection, featuring compact size, cost-effectiveness, and rapid response. This review summarizes the most recent five-year research advances in cancer biomarker detection, and clarifies the core mechanisms of electrical property changes from sensing material-VOCs interactions and key performance metrics including sensitivity, selectivity, humidity tolerance, response/recovery time, stability, and operating temperature. This review also highlights the optimization strategies of sensing materials such as metal doping, surface modification, heterostructure fabrication, and metal oxide-carrier composite synthesis to enhance trace detection, selectivity, and stability via expanded specific surface area, the introduction of active sites and interfacial charge transfer modulation. Finally, this review outlines sensor arrays integrated with machine learning for precise cancer recognition. This review provides theoretical support for the performance optimization and clinical translation of MOS sensors, and facilitates their widespread application in the non-invasive early diagnosis of cancers.