MEASURE: Multiplex Exhaled Breath Condensate - Scanning Using Rapid Electro-Analytics.

Exhaled breath condensate is an emerging source of inflammatory biomarkers suitable for the noninvasive detection of respiratory disorders. Current gold standard methods are highly invasive and pose challenges in sample collection during airway inflammation monitoring. Cytokine biomarkers are detectable in EBC at increased or decreased concentrations. IL-6, IL-1ß, IL-8, and hs-CRP are characteristic biomarkers identified in respiratory disorders. We have demonstrated the promising outcomes of a 16-plexed electrochemical platform - READ 2.0 for the multiplexed detection of characteristic biomarkers in EBC. The sensor demonstrates dynamic ranges of 1-243 pg/mL with a lower detection limit of 1 pg/mL for IL-6 and IL-1ß, while the detection range and limit of detection for IL-8 and hs-CRP is 1-150 pg/mL and 3 pg/mL, respectively. The detection accuracies for the biomarkers are in the range of ∼85 ± 15% to ∼100 ± 10%. The sensor shows a nonspecific response to similar cross-reacting biomarkers. Analytical validation of the sensor with ELISA as the standard reference generated a correlation of R2 > 0.96 and mean biases of 10.9, 3.5, 17.4, and 3.9 pg/mL between the two methods for IL-6, IL-1ß, IL-8, and hs-CRP, respectively. The precision of the sensor in detecting low biomarker concentrations yields a %CV of <7%. The variation in the sensor's response on repeat EBC sample measurements and within a 6 h duration is less than 10%. The READ 2.0 platform shows a promise that EBC-based biomarker detection can prove to be vital in predicting the severity and survival rates of respiratory disorders and serve as a reference point for monitoring EBC-based biomarkers.

EBC-SURE (exhaled breath condensate- scanning using rapid electro analytics): A non-faradaic and non-invasive electrochemical assay to screen for pro-inflammatory biomarkers in human breath condensate.

The innovation of this work lies in the trace detection of inflammatory biomarkers (IL-6, hs-CRP) in human exhaled breath condensate on the developed EBC-SURE platform as a point-of-care aid for respiratory disorder diagnosis. The unique design of the EBC-SURE leverages non-faradaic electrochemical impedance spectroscopy to capture target-specific biomolecular interactions for highly sensitive biomarker detection. For sensor calibration, EBC-SURE's performance is assessed to measure the response of the sensor to a known concentration by spike and recovery analysis with a recovery error of <20% and an extended dynamic range over 3-log orders. The lowest detection limits for IL-6 and hs-CRP detection in EBC were found to be 3.2 pg/mL and 4 pg/mL respectively. The intra-assay and inter-assay efficacy of EBC-SURE for its usage as a diagnostic device was established through repeatability and reproducibility (over 48 h s) performance testing. The percentage variations (<20%) met the Clinical and Laboratory Standards Institute standards (CLSI) indicating a highly stable performance for robust biomarker detection. EBC-SURE generated highly selective IL-6 and hs-CRP responses in the presence of other non-specific cytokines. Statistical validation methods- Correlation and Bland Altman analysis established the one-to-one agreement between EBC-SURE and the reference method. Correlation analysis generated a Pearson's R value of 0.99 for IL-6 and hs-CRP. Bland-Altman analysis indicated a good agreement between both the methods with all data points confined within the ±2SD limits. We have demonstrated EBC-SURE's ability in detecting inflammatory biomarkers in human breath condensate towards developing a non-invasive technology that can quantify biomarker levels associated with healthy and acute inflammatory conditions.

Temporal profiling of cytokines in passively expressed sweat for detection of infection using wearable device.

This work presents the viability of passive eccrine sweat as a functional biofluid toward tracking the human body's inflammatory response. Cytokines are biomarkers that orchestrate the manifestation and progression of an infection/inflammatory event. Hence, noninvasive, real-time monitoring of cytokines can be pivotal in assessing the progression of infection/inflammatory event, which may be feasible through monitoring of host immune markers in eccrine sweat. This work is the first experimental proof demonstrating the ability to detect inflammation/infection such as fever, FLU directly from passively expressed sweat in human subjects using a wearable "SWEATSENSER" device. The developed SWEATSENSER device demonstrates stable, real-time monitoring of inflammatory cytokines in passive sweat. An accuracy of >90% and specificity >95% was achieved using SWEATSENSER for a panel of cytokines (interleukin-6, interleukin-8, interleukin-10, and tumor necrosis factor-α) over an analytical range of 0.2-200 pg mL-1. The SWEATSENSER demonstrated a correlation of Pearson's r > 0.98 for the study biomarkers in a cohort of 26 subjects when correlated with standard reference method. Comparable IL-8 levels (2-15 pg mL-1) between systemic circulation (serum) and eccrine sweat through clinical studies in a cohort of 15 subjects, and the ability to distinguish healthy and sick (infection) cohort using inflammatory cytokines in sweat provides pioneering evidence of the SWEATSENSER technology for noninvasive tracking of host immune response biomarkers. Such a wearable device can offer significant strides in improving prognosis and provide personalized therapeutic treatment for several inflammatory/infectious diseases.