Rapid quantitative analysis of tobacco smoking in saliva using a TRPA1 ion channel-mediated bioelectronic tongue inspired by the human sensory system

Abstract

To stop smoking is often hampered by the addictive nature of nicotine, even when smokers are aware of its harmful effects. Hence, healthcare providers should manage cessation programs for smokers. A quantitative method of analyzing tobacco use is needed to accurately diagnose addicted smokers and provide alternatives, such as nicotine patches. Although numerous sensors have been developed to measure levels of nicotine that reflect tobacco smoking, those that analyze saliva from smokers remains challenging in terms of on-site application. We therefore constructed a biomimetic system using the human smoking-responsive respiratory tract receptor, transient receptor potential ankyrin 1 (TRPA1), to quantify amounts of smoking. TRPA1-overexpressed nanovesicles (TRPA1-NV) were attached to a carbon nanotube (CNT) electrode coated with a Ca2+ ion selective membrane (TRPA1-NV/ISM-CNT) to prevent non-selective responses and detect TRPA1-mediated Ca2+ movement. The TRPA1-NV/ISM-CNT sensor detected pM levels of nicotine and crotonaldehyde in saliva from smokers and did not respond to capsaicin, glucose, and acetic acid, that are potential contaminants in saliva. Our sensor dose-dependently responded to artificial saliva exposed to tobacco smoke and to saliva from smokers, without complex preparatory processes. Our TRPA1-NV/ISM-CNT sensor rapidly and accurately quantified salivary nicotine and crotonaldehyde that indicate smoking habits in real time on-site.