Highly Sensitive Tungsten Oxide Thin Film‐Based Field‐Effect Transistor for Real‐Time Monitoring of Dissolved Ammonia in Human Plasma

Abstract

Field‐effect transistors (FETs) based on metal‐oxide thin film have the advantage of excellent sensitivity, fast response, miniaturized size, and compatibility with bio‐analytes. In this work, a highly responsive FET biosensor is fabricated based on tungsten trioxide (WO3) thin film to detect the physiological concentration of total ammonia (ammonium NH4+ and NH3) in human body fluids. The elevated level of ammonia in the body fluids indicates damage or improper functioning of organs mainly the liver. Thus, real‐time monitoring of ammonia concentration in human body fluid acts as a prognostic marker for liver disorders. The fabricated FET device shows reliable and accurate results for ammonia sensing with the highest response of 498 at 100 µM and a limit of detection of 6 µM. This device measures the ammonia in body fluid faster than available techniques and shows a high response towards ammonia in commercially available human plasma. This is also capable of real‐time detection of very low concentrations of ammonia (2 µM) with a wide range from 2 to 100 µM. Also, the prospect of the device's batch fabrication is demonstrated with consistent and high stability performance. This study demonstrates a unique and stable sensing platform, capable of direct detection of ammonia concentration in human plasma for point of care applications.

Hybrid MoSe2/P3HT Transistor for Real-Time Ammonia Sensing in Biofluids

“…The biosensing of the hybrid device was performed by obtaining the electrical characteristics of the fabricated sensor with different concentrations of ammonia in saliva and plasma. Before performing the ammonia measurements with the hybrid device, a standard ammonia assay kit verified the ammonia concentration in saliva and plasma, as mentioned in our previous report …”

“…Before performing the ammonia measurements with the hybrid device, a standard ammonia assay kit verified the ammonia concentration in saliva and plasma, as mentioned in our previous report. 17 Real-Time Ammonia Sensing in Biofluids. Having verified the formation of a hybrid channel layer for BioFET and getting the operational stability from the device's electrical characteristics, the next step was to evaluate the sensing performance of hybrid FET for ammonia detection in saliva and plasma.…”

“…AA0100), as mentioned in our previous study. 17 Characterization. The formation of an organic−inorganic hybrid FET channel layer was confirmed by FESEM and EDX elemental mapping (FESEM TSCAN).…”

“…15,16 Early, regular, or online monitoring of blood or plasma ammonia levels is critical. 10,17 Various analytical approaches for ammonium detection have been reported, including chromatography, spectrophotometry, and electrochemistry in saliva or plasma. 18−20 Despite being very precise in identifying ammonia, these approaches are so time-consuming that they are unsuitable for point-of-care (POC) monitoring and real-time monitoring of ammonia.…”

Highly Sensitive Transistor Sensor for Biochemical Sensing and Health Monitoring Applications: A Review

“…An accurate monitoring of ammonia concentration in plasma is essential for diagnosing end-stage liver diseases like liver cirrhosis. Sharma et al [76] developed a highly sensitive tungsten trioxide (WO3) FET biosensor to detect total ammonia (ammonium NH4 + and NH3) in human body fluid for early-stage diagnosis of chronic liver disease. The FET device exhibited a good response of 498 at 100 µM, LOD of 6 µM with real-time detection capability at low concentration (2 µM) for ammonia detection.…”