A Portable Sweat Sensor Based on Carbon Quantum Dots for Multiplex Detection of Cardiovascular Health Biomarkers

Abstract

The future of personalized diagnostics and treatment of cardiovascular diseases lies in the use of portable sensors. Portable sensors can acquire biomarker information in biological fluids such as sweat, an approach that mitigates the shortcomings of conventional hospital-centered healthcare. Low sensitivity, selectivity, and specificity remain bottlenecks for the widespread use of portable sensors. Herein, we demonstrate a portable sensor that simultaneously detects Na+, ascorbic acid, and human neuropeptide Y in sweat, all useful biomarkers to index cardiovascular health. The portable sensor comprises a six-electrode system containing three working electrodes, two reference electrodes, and one counter electrode. The working electrodes were prepared by depositing sensing components on carbon quantum dot (CQD) electrodes. The sensing mechanisms were based on selective ion recognition, enzyme catalytic reaction, and immune response, which guarantees specificity to corresponding targets. The CQDs offer massive reactive sites and effectively reduce the interfacial impedance during the sensing reaction, thereby enhancing the three biomarkers’ detection sensitivity. As evidence of portable sensor capability, we demonstrate herein its effective simultaneous detection of the three biomarkers in a real sweat from healthy volunteers during routine activities including exercise, extra ascorbic acid ingestion, and extra Na+ ingestion. As such, the sensor shows promise for real-time noninvasive personalized medical diagnostics and metabolic wellness management.

Recent Advances in Cardiovascular Disease Biosensors and Monitoring Technologies

“…One good example is a portable sensor for Na + , ascorbic acid, and human neuropeptide Y measurement from sweat. 116 These parameters were found to be correlated to cardiovascular health and could be further studied to establish more reliable disease indication. Saliva sampling could be another alternative physiological fluid in future diagnostic biosensor research whose feasibility has been validated by several studies.…”

Electrochemical Nanosensors for Sensitization of Sweat Metabolites: From Concept Mapping to Personalized Health Monitoring

“…There are a good number of literature reports where AA can be detected by enzymatic sensors. Recently, Zhang et al have reported a portable sweat sensor comprised of six electrodes based on carbon quantum dots for selective and sensitive recognition of AA [ 77 ], where the recognition phenomenon proceeds through an enzymatic catalytic reaction. CQD has been chosen as the electrode substrate material of the electrochemical sensors for immobilization of enzymes because of their large surface area [ 78 ] and abundant active sites for effectual reduction of the interfacial impedance to increase the sensitivity of the sensor [ 79 ].…”

“… ( a ) Schematic illustration of the mechanistic pathway of sensing, ( b ) amperometric response of the sensor in presence of 1–400 µM AA in artificial sweat, adopted with permission from Ref. [ 77 ]. …”

An Integrated Wearable Sweat Sensing Patch for Passive Continuous Analysis of Stress Biomarkers at Rest

“…Wearable sensors can overcome this issue by conducting in situ sweat analysis for real-time results. [21][22][23][24][25][26] Wearable sensors have been demonstrated for detecting numerous metabolites such as glucose, [17,22,24,[27][28][29] uric acid, [30,31] ascorbic acid, [32,33] ions, [34][35][36][37][38] etc. A robust selfpowered sweat sensor was developed by Li and coworkers which shows the capability of sensing the concentration fluctuations of Na + and K + during exercises.…”