Porous Oxide-Functionalized Seaweed Fabric as a Flexible Breath Sensor for Noninvasive Nephropathy Diagnosis

Abstract

Ever-increasing quality of life demands low-power and reliable gas-sensing technology for point-of-care monitoring of human health by relevant breath biomarkers. However, precise identification is rather challenging due to the relatively small concentration and an abundance of interferents. Herein, a breath sensor that can detect ppb-level ammonia is constructed based on a soft–hard interface design of biocompatible seaweed fabric and nanosheet-assembled bismuth oxide architectures after undergoing heat treatment. Benefiting from abundant defective sites and surface chemical state changes, the flexible sensor can work at room temperature and exhibits superior characteristics for ammonia detection, including ultrahigh response (1296), short response/recovery time (12/6 s), small detection limit (117 ppb), and remarkable anti-interference, even after repetitive mechanical bending and long-term fatigue. Furthermore, the flexible sensor demonstrates a noticeable response to the exhaled breath of a patient with Helicobacter pylori infection. After connecting the sensor with a green-light-emitting diode (LED) in the circuit, an alarm system successfully warns about ammonia levels based on the brightness of the LED. This work provides a potential strategy for wide-range ammonia detection and opens new applications in predictive and personalized healthcare platforms for noninvasive medical diagnosis.

Wearable Dual-Signal NH3 Sensor with High Sensitivity for Non-invasive Diagnosis of Chronic Kidney Disease

“…In addition to nitrogen, carbon dioxide, oxygen, and water, the exhaled breath of the human body also contains volatile organic compounds (VOCs), such as NH 3 , acetone, hydrogen sulfide, nitrogen oxides, toluene, ethanol, etc. These volatile gases contain rich physiological information, which can be used as biomarkers of diseases. − If the concentration of NH 3 in the breath increases, humans are likely to suffer from CKD. − The reason is that NH 3 is mainly produced by protein metabolism in the human body, which turns into urea through urea circulation, and is discharged by the kidney along with urine. In the case of CKD, urea is unable to be removed, which can lead to excess NH 3 build-up.…”

rGO-Modified ZnWO4/WO3 Nanocomposite for Detection of NH3

“…4 Among them, the metal-oxide sensor has the advantages of small size, high sensitivity, and low cost, so it has become the most promising chemical sensor device. 5,6 Nowadays, a large number of metal-oxide semiconductor-based sensors, such as ZnO, 7 WO 3 , 3 TiO 2 , 8 and Bi 2 O 3 , 9 have been studied for the detection of ammonia. 10 WO 3 gas sensors are widely used in the detection of toxic and volatile gases such as NH 3 due to their wide band gap, low-cost synthesis, good response to target gases, superior chemical stability, and environmental friendliness.…”

“…At present, the following four types of NH 3 gas sensors have been developed based on different principles: resistance-based semiconductor metal-oxide (SMO) sensors, electrochemical sensors, optical sensors, and quartz crystal microbalance sensors . Among them, the metal-oxide sensor has the advantages of small size, high sensitivity, and low cost, so it has become the most promising chemical sensor device. , Nowadays, a large number of metal-oxide semiconductor-based sensors, such as ZnO, WO 3 , TiO 2 , and Bi 2 O 3 , have been studied for the detection of ammonia …”

I-V characteristics and adsorption properties of ZnO/rGO/ZnO for gas sensing detection

“…The heterojunction still exhibits good gas-sensitive properties at 300 times mechanical bending, indicating excellent repeatability and durability. Zhang et al [3] designed a flexible B4SF sensor based on the flame-retardant seaweed fabric, which exhibits ultrahigh response (1296) for ammonia detection to promote the application of non-invasive human health monitoring. Therefore, the research of highly sensitive and selective flexible thin-film sensors is of great significance.…”