Recent advances of non-invasive sensors for smart wearable respiratory monitoring

Abstract

Human respiration, containing rich physiological and pathological information, is one of the most fundamental and continuous vital signs. Smart respiratory monitoring systems, which combine functional materials, microelectronics, and technologies such as artificial intelligence and wireless communication, have been intensively explored. Many promising applications in healthcare, sports and fitness, the Internet of Things, and so forth have been demonstrated worldwide. A timely and comprehensive review of progress in this field is provided. However, most existing reviews mainly summarize sensing mechanisms or device structures, while lacking an integrated analysis that links human respiratory characteristics with the design principles and material strategies of non-invasive wearable respiratory sensors. To address this gap, this work provides a timely and comprehensive review focusing specifically on material-oriented advances in wearable non-invasive respiratory sensors and their physiological relevance. Several main aspects are covered: characteristics of human respiration, key monitoring parameters, functional materials, novel sensors, and wearable applications. This paper places particular emphasis on how innovative materials empower non-invasive respiratory sensors across various categories to achieve enhanced sensitivity, stability, wearability, and multimodal sensing capabilities. The major types of wearable non-invasive respiratory sensors are discussed in detail. This paper also discusses the future research trends and prospects of these sensors.