Wireless Detection of Trace Ammonia: A Chronic Kidney Disease Biomarker

Abstract

Elevated levels of ammonia in breath can be linked to medical complications, such as chronic kidney disease (CKD), that disturb the urea balance in the body. However, early stage CKD is usually asymptomatic, and mass screening is hindered by high instrumentation and operation requirements and accessible and reliable detection methods for CKD biomarkers, such as trace ammonia in breath. Enabling methods would have significance in population screening for early stage CKD patients. We herein report a method to effectively immobilize transition metal selectors in close proximity to a single-walled carbon nanotube (SWCNT) surface using pentiptycene polymers containing metal-chelating backbone structures. The robust and modular nature of the pentiptycene metallopolymer/SWCNT complexes creates a platform that accelerates sensor discovery and optimization. Using these methods, we have identified sensitive, selective, and robust copper-based chemiresistive ammonia sensors that display low parts per billion detection limits. We have added these hybrid materials to the resonant radio frequency circuits of commercial near-field communication (NFC) tags to achieve robust wireless detection of ammonia at physiologically relevant levels. The integrated devices offer a noninvasive and cost-effective approach for early detection and monitoring of CKD.

Ppb-Level Ammonia Sensor for Exhaled Breath Diagnosis Based on UV-DOAS Combined with Spectral Reconstruction Fitting Neural Network

“…Levels of such substances always correlate with the severity of specific diseases and are biomarkers for health disorders. Measuring these substances makes it possible to early identify and treat various diseases in the medical field. − In particular, ammonia (NH 3 ) in EB is used as a biomarker for screening and diagnosis of liver and kidney impairment. − Since kidney injury can indirectly affect liver function, leading to changes in NH 3 concentration in exhaled breath, the development of ultrasensitive online NH 3 sensor at parts per billion (ppb) level for detecting breath NH 3 is a matter of urgency.…”