Abstract
Sensitive and selective detection of acetone in human exhaled breath plays an important role in the diagnosis of diabetes. However, obtaining a reliable response to ppb levels of acetone and avoiding cross-sensitivity due to the large amount of moisture in exhaled breath are still great challenges. In this work, a type of acetone sensor with ultrahigh sensitivity and moisture resistance is reported. Electrospun In2O3 nanowires with a controllable Pt core (Pt@In2O3 core-shell nanowires) are designed and prepared as sensitive layers. A mesoporous silica molecular sieve is further integrated as the moisture filter layer. The Pt@In2O3 core-shell nanowire-based sensor exhibits a highly improved response compared with a sensor based on pure In2O3 nanowires due to the probable increase in surface resistance and the introduction of p–n junctions after rational design of the structure. In addition, a good performance in terms of the fast dynamic process, selectivity and long-term stability is also achieved, and the detection limit can be as low as 10 ppb, which is much lower than the concentration level of 1.8 ppm in the exhaled breath of diabetic patients. The influence of the large amount of moisture is greatly weakened by using the molecular sieve as a moisture filter layer, leading to much improved sensitivity in clinical sample detection among healthy and diabetic patients. Based on the optimized composite structure of the Pt@In2O3 core-shell nanowire sensor and moisture filter layer, a simple portable sensing prototype is successfully fabricated. The reported Pt@In2O3 core-shell nanowires and the acetone sensing approach open up a new opportunity for a simple, inexpensive, and noninvasive diagnosis of diabetes.
Highlights
Diabetes is a global chronic disease arising from metabolic disturbances[1]
For n-type SMObased gas sensors, the sensing mechanism is mainly based on the surface chemical redox reactions that occur between surface absorbed oxygen ions and target gases, which will change the amount of electrons in n-type semiconductor oxide (SMO) and change the corresponding resistance
A schematic illustration of the process of producing the Pt@In2O3 core-shell NWs is shown in Fig. 1a
Summary
Diabetes is a global chronic disease arising from metabolic disturbances[1]. Traditional methods for conducting blood glucose measurements during both hospital examinations and in-home care are invasive, which undoubtedly causes patients to undergo additional psychological stress and pain[2]. It is reported that diabetes can be reflected by a biomarker in human breath, i.e., The semiconductor oxide (SMO)-based gas sensor is one of the most promising devices for practical detection related to, for example, personal health[4], air pollution[5], and safety protection areas[6] due to its key advantages in terms of high sensitivity, fast response and recovery dynamics, ease of operation and low cost[7,8]. For n-type SMObased gas sensors, the sensing mechanism is mainly based on the surface chemical redox reactions that occur between surface absorbed oxygen ions and target gases, which will change the amount of electrons in n-type SMOs and change the corresponding resistance. One key method for significantly improving the sensing performance is to introduce noble metal catalytic additives into the nanostructured SMOs to sensitize the corresponding reactions[13]. Regarding the metal core@SMO shell structure, the metal core can effectively help increase the conductivity and catalyze the reaction
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