A Versatile Method to Enhance the Operational Current of Air-Stable Organic Gas Sensor for Monitoring of Breath Ammonia in Hemodialysis Patients

Abstract

Point-of-care (POC) application for monitoring of breath ammonia (BA) in hemodialysis patients have emerged as a promising non-invasive health monitoring approach. In this context, many organic gas sensors have been reported for BA detection. However, one of the major challenges for its integration with portable POC application is to achieve long lifetime and high operational current at low voltage. Herein, we propose a double active layer (DL) strategy that exploits an ultra-thin layer of Poly(3hexylthiophene-2,5-diyl) (P3HT) to serve as a work function buffer, combined with an acceptor-donor polymer Poly [[4,8-as a new sensing material. We show that the DL sensor exhibits a sustainable enhanced operational current of microampere level and a stable sensing response even with the presence of P3HT layer. This effect is carefully examined with different aspect, including vertical composition profile of DL configuration, lifetime testing on different sensing layer, morphological analysis, and the versatility of the DL strategy. Finally, we utilize the CT/P3HT-DL sensor to conduct a long-term tracing of BA concentration in two hemodialysis (HD) patients before and after HD, and correlate it with the blood urea nitrogen (BUN) levels. A good correlation coefficient of 0.96 is achieved. The result demonstrates the potential of this DL strategy to be used to integrate organic sensor in POC devices.

Self‐Powered Respiration Monitoring Enabled By a Triboelectric Nanogenerator

“…In recent decades, various techniques have already shown promising results in respiratory analysis, including quartz crystal microbalance (QCM), [ 34 ] ion mobility spectrometry (IMS), [ 35,36 ] proton‐transfer‐reaction mass spectrometry (PTR‐MS), [ 37 ] gas chromatography, [ 38 ] surface acoustic wave (SAW), [ 39–41 ] differential mobility spectroscopy (DMS), [ 42 ] thin film transistor (TFT), [ 43–45 ] chemoresistive sensor, [ 46–50 ] and so on. However, a majority of them require an external power source and batteries are widely adopted.…”

Recent Advances in Ammonia Gas Sensors Based on Carbon Nanomaterials

“…The positive subjects had lower concentrations of ammonia (0.04 ± 0.09 ppm) compared to negative subjects (0.49 ± 0.24 ppm), whereas patients that underwent treatment showed values of ammonia concentration that changed from positive to negative. One of the main advantages of the application of chemiresistive gas sensors for breath analysis is the correlation between the concentration of ammonia in breath and blood urea nitrogen [19], which makes the use of these sensors more convenient and simple for medical diagnostics.…”

Copper Fluoride Doped Polypyrrole for Portable and Enhanced Ammonia Sensing at Room Temperature

“…The abnormal functioning of the kidneys defined as chronic kidney disease (CKD) [3] and it's generally resulting from many heterogeneous disorders that irreversibly affect the kidney [4] . Because of kidney malfunctioning and inadequate elimination of urea, CKD patients have higher urea levels in the blood and, need dialysis treatment to eliminate the urea from the blood [5] . The inadequate dose of dialysis could result in organ failure and rapid death [6] .…”

“…Gas chromatography‐mass spectrometry (GC‐MS) is a standard technique for the detection of VOCs in the exhaled breath [10d,12] . However, these techniques are complex, expensive, and not sufficient for point‐of‐care applications [5] . Therefore, a low‐cost, handheld, real‐time, and point of care device is required to control the health condition in the CKD and dialysis patients.…”