We reported a skin-interfaced wearable aptamer nanobiosensor based on target-induced strand displacement for automatic and non-invasive monitoring of estradiol via in situ sweat analysis. The reagentless, amplification-free, and “signal-on” detection approach coupled with gold nanoparticles-MXene-based detection electrode offers extraordinary sensitivity with an ultra-low limit of detection of 0.14 pM. This fully-integrated system is capable of autonomous sweat induction at rest via iontophoresis, precise microfluidic sweat sampling controlled via capillary bursting valves, real-time estradiol analysis and calibration with simultaneously collected multivariate information (i.e., temperature, pH, and ionic strength), as well as signal processing and wireless communication with a user interface (e.g., smartphone). We validated the technology in human subjects. Our data suggests a cyclical fluctuation in sweat estradiol during menstrual cycles. A high correlation between sweat and blood estradiol was identified for the first time, indicating the great promise of using wearable sensors for non-invasive reproductive hormone monitoring

Through a strategic integration of the mass-producible laser-engraved graphene, redox-active nanoreporters, biomimetic ‘artificial antibodies’, along with in situ regeneration technologies, we propose a universal sensing strategy toward continuous analysis of a number of trace-level metabolites and nutrients including all essential amino acids and vitamins. Consolidated with localized sweat stimulation, microfluidic sweat sampling, and on-board signal calibration, we demonstrate a wearable platform for prolonged metabolic and nutritional monitoring across activities, during physical exercise and at rest. Through multiple human studies, we demonstrate this platform’s high potentials toward real-time monitoring of dietary nutrient intakes, central fatigue, risks of metabolic syndrome, and COVID-19 severity. 

We introduce QuantumDock, an automated computational framework for universal MIP development toward a wide range of wearable applications. QuantumDock utilizes density functional theory to probe molecular interactions between monomers and the target/interferent molecules to optimize selectivity, a fundamentally limiting factor for MIP development toward wearable sensing. A molecular docking approach is employed to identify the optimal monomer and crosslinker for subsequent MIP fabrication. Using an essential amino acid phenylalanine as the exemplar, we performed successful experimental validation of QuantumDock using solution-synthesized MIP nanoparticles coupled with ultraviolet–visible spectroscopy. Moreover, we designed a QuantumDock-optimized laser-engraved graphene-based wearable device that can perform autonomous sweat induction, sampling, sensing, and calibration at rest. We, for the first time, demonstrate the wearable non-invasive phenylalanine monitoring in human subjects toward personalized healthcare application.

We reported an entirely laser-engraved sensor for simultaneous sweat sampling, chemical sensing, and vital sign monitoring. Evaluate its utility for gout monitoring in patients and healthy controls through a purine-rich meal challenge. Levels of uric acid in sweat were higher in patients with gout than in healthy individuals, and a similar trend was observed in serum.

Nature Biotechnology, 2020, 38, 217-224.  

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We reported the first cortisol diurnal cycle and the dynamic stress-response profile constructed from human sweat. Our pilot study demonstrates a strong empirical correlation between serum and sweat cortisol, revealing exciting opportunities offered by sweat analysis toward non-invasive dynamic stress monitoring via wearable and portable sensing platforms.

Matter, 2020, 2, 921-937.  

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