Temporal Profiling of Cytokines in Passively Expressed Sweat for Detection of Infection Using the AWARE Device

This study highlights the assay development of a wearable AWARE-SENSOR (a wearable awareness with real-time exposure) designed for the noninvasive detection of key pro-inflammatory cytokines, TNF-α and IL-6, in passively perspired sweat. These cytokines are pivotal biomarkers for assessing immune responses, inflammation, and physiological stress. A critical innovation in this platform is the use of aptamers, which offer significant advantages over traditional antibodies in biosensor applications. Aptamers, being synthetic oligonucleotides, are highly specific to their target molecules, providing robust and reproducible binding. Unlike antibodies, aptamers exhibit superior stability under varying environmental conditions, such as temperature, making them ideal for real-time and human body deployable applications, such as wearable sensors. The use of aptamers ensures that the AWARE-SENSOR achieves precise and continuous monitoring capabilities, translating cytokine binding into measurable electrical signals. These features make the device particularly suitable for tracking dynamic changes in inflammatory biomarkers. Herein, we report benchtop validation of a new aptamer sensor for the detection of TNF-α and IL-6 in PBS. The dynamic ranges of TNF-α and IL-6 were 0.1-200 and 1-256 pg/mL, respectively, with sensitivities of 2.77 pg/mL (TNF-α) and 3.22 pg/mL (IL-6) with linear responses R² = 0.98 (TNF-α) and R² = 0.97 (IL-6). Interference studies confirmed that the sensor exhibited no significant interference from biomarkers like IL-6, IL-8, and CRP for the TNF-α sensor and vice versa. The AWARE-SENSOR response was also evaluated to detect the biomarkers in human sweat samples with high accuracy within ∼3 min of incubation. The sensing mechanism of the AWARE-SENSOR suggested that the binding of the biomarker to the aptamer on the electrode surface alters the electrical properties of the interface, typically by creating a more conductive pathway due to conformational changes in the aptamer, effectively allowing more electrons to transfer between the electrode and the solution, leading to a lower impedance reading.