A Self-Powered Breath Analyzer Based on PANI/PVDF Piezo-Gas-Sensing Arrays for Potential Diagnostics Application

In recent years the increasing morbidity of internal diseases induced by unwholesome diet and working behaviors has posed a serious threat to human health and quality of life [ 1 , 2 , 3 ]. Early detection and treatment play key roles in improving the cure rate of the patients [ 4 ]. Although conventional blood examination methods have been developed with good sensitivity and stability [ 5 ], a noninvasive, portable, and convenient diagnostic method is urgently needed for a wide range of early diagnoses and high-risk population screening [ 6 ]. As an important physiological process for human beings, breath is one of the most important ways to exchange substances between the human body and outside world. Various studies suggest that exhaled breath, containing a large number of metabolic products, includes gas species and concentrations closely associated with human health as indicators of certain diseases [ 7 , 8 , 9 , 10 , 11 , 12 ]. For example, ethanol in exhaled breath is recognized as a gas marker of fatty liver; oxynitride (NO x ) is a gas marker of airway inflammation; acetone is a gas marker of diabetes; methane (CH 4 ) is a gas marker of liver cirrhosis; and carbon monoxide (CO) is a gas marker of asthma. However, exhaled breath analyzers are restricted by possible limitations, such as high cost, structure complexity, need for high-quality materials, and reliance on external power sources.