Nicotine, an addictive substance in cigarettes and e-cigarettes (“vapes”), increases the risk of, e.g., cardiovascular and respiratory disorders. Assessing nicotine exposure under real-world conditions can be challenging. Current methods for measuring ambient nicotine levels are usually carried out in laboratory settings and require large sample volumes and days to weeks of sampling. Portable, practical, real-time nicotine monitoring devices could help to get a full understanding of the health effects of nicotine and allow researchers to measure the exposure of both vapers and those exposed via second-hand smoke.

Md. Ataur Rahman, Madhu Bhaskaran, RMIT University (Royal Melbourne Institute of Technology), Melbourne, Australia, Philipp Gutruf, University of Arizona, Tucson, USA, have developed a lightweight, battery-free, wearable sensor that can detect nicotine in real time and send the data wirelessly to electronic devices such as a smartphone. The team used vanadium dioxide (VO₂) on a polyimide substrate as the basis for their sensor. They showed that nicotine can bond covalently to a thin film of VO₂ and change the film’s conductivity to an extent that depends on nicotine concentration. The sensor was integrated into a small, flexible, near-field communication (NFC)-enabled device that can harvest the small amounts of energy that it needs wirelessly during readout.

The device detects the change in conductivity, amplifies the signal, and then transmits it wirelessly to a smartphone. When applied to the skin, the battery-free sensor can measure the wearer’s exposure to vaporized nicotine in open air. According to the researchers, this approach expands the use of wearable electronics for real-time monitoring of hazardous substances in the environment.

• Nicotine Sensors for Wearable Battery-Free Monitoring of Vaping,
  Md. Ataur Rahman, Le Cai, Sherif Abdulkader Tawfik, Stuart Tucker, Alex Burton, Ganganath Perera, Michelle J. S. Spencer, Sumeet Walia, Sharath Sriram, Philipp Gutruf, Madhu Bhaskaran,
  ACS Sens. 2021.
  https://doi.org/10.1021/acssensors.1c01633