MXene-enabled gas sensors for wearable breath monitoring

The convergence of personalized healthcare and IoT-driven diagnostics has intensified demand for non-invasive, real-time respiratory monitoring to address global aging populations and pervasive sub-health conditions. Breathing gases, carrying dynamic biomarkers ranging from volatile organic compounds to inflammatory cytokines, are enabling early detection of cardiopulmonary and metabolic disorders for health assessment and illness prediction. While conventional sensors struggle with selectivity and stability in humid environments or room temperature, MXene-based sensors emerge as a paradigm-shifting solution by leveraging MXenes' two-dimensional (2D) atomic-scale tunability, metastable surface chemistry, and interfacial charge-transfer adaptability. Recent advances in materials hybridization and structure design have brought tremendous opportunities in wearable MXene-based sensors for real-time or remote healthcare. Despite growing interest in gas sensing, comprehensive reviews of MXene-based materials toward gas sensors remain limited. This review focuses on recent advances in breathing gas monitoring with MXene-based materials, particularly the role of MXene-based materials in enhancing sensing ability. We begin with a brief overview of the historical development and major achievements in MXene-based sensing materials, spotlighting MXene’s unique synergy with metal oxides (enhanced activity), polymers (mechanical resilience), and carbon networks (electron highways) to create multimodal sensing architectures. Followed by an elucidation of the mechanism built on chemiresistive effect, the adoption of these materials to detect disease-associated gas biomarkers in practical application scenarios is discussed elaborately. Finally, the review addresses challenges and proposes solutions such as material modification, doping, and compositing as well as proper structural design and integration. The goal of this review is to stimulate further innovative studies on MXene-based sensors and to promote their practical implementation in real.