A wearable nanofluidic sensor for determining the sweat nicotine

The escalating prevalence of electronic cigarettes has intensified public health discourse regarding the implications of nicotine exposure. Consequently, the development of rigorous, non-invasive diagnostic methodologies to evaluate secondhand smoke exposure is imperative. Precise quantification of nicotine levels provides a critical evidence base for designing interventions aimed at smoking cessation and the prophylaxis of smoking-related pathologies. In this study, we introduce a novel biosensing paradigm that leverages the I-V characteristics of asymmetric nanochannel arrays, synergized with the selective enzymatic activity of nicotine oxidase (CYP2B6), for the detection of sweat nicotine. The nanoconfinement effect within these arrays significantly enhances the affinity of CYP2B6 for nicotine, thereby augmenting catalytic efficiency. The developed wearable sensor demonstrates exceptional analytical performance, featuring a bilinear range (0.1 to 9 μM and 10-50 μM) and robust immunity to common sweat-borne interferences, such as glucose and uric acid. Furthermore, the platform exhibits a low limit of detection (0.3 μM) at low nicotine concentration range, underscoring its clinical utility for the sensitive quantification of nicotine exposure. We assessed nicotine levels in human populations, including high smokers, low smokers, secondhand smokers, and non-smokers. The results indicated that a clear increase in nicotine levels correlating with the duration of smoking. Thus, the continuous and personalized wearable sweat nicotine detection sensor based on the proposed detection method can effectively monitor nicotine exposure across a diverse range of populations.