Antibody-Coated Wearable Organic Electrochemical Transistors for Cortisol Detection in Human Sweat

Abstract

The dysregulation of the hormone cortisol is related to several pathological states, and its monitoring could help prevent severe stress, fatigue, and mental diseases. While wearable antibody-based biosensors could allow real-time and simple monitoring of antigens, an accurate and low-cost antibody-based cortisol detection through electrochemical methods is considerably challenging due to its low concentration and the high ionic strength of real biofluids. Here, a label-free and fast sensor for cortisol detection is proposed based on antibody-coated organic electrochemical transistors. The developed devices show unprecedented high sensitivities of 50 μA/dec for cortisol sensing in high-ionic-strength solutions with effective cortisol detection demonstrated with real human sweat. The sensing mechanism is analyzed through impedance spectroscopy and confirmed with electrical models. Compared to existing methods requiring bulky and expensive laboratory equipment, these wearable devices enable point-of-care cortisol detection in 5 min with direct sweat collection for personalized well-being monitoring.

Introducing Nanoscale Electrochemistry in Small-Molecule Detection for Tackling Existing Limitations of Affinity-Based Label-Free Biosensing Applications

“…The present MICP-based sensor can detect salivary cortisol levels in less than 14 min (4 min for cortisol binding time and 10 min for quantum conductance measurements). The total analysis time of the present method is comparable to most aptamer- or MIP-based cortisol (bio)­sensors (binding time: around or less than 10 min), − and even shorter than other antibody-based cortisol biosensors (binding time: at least 1 h) . Furthermore, the quantum conductance measurement time can be further reduced to less than 4 min by monitoring the quantum conductance at a selected frequency (1.35 Hz) instead of scanning a full range frequency scan (10 kHz–0.01 Hz), thus leading to a total time of less than 10 min.…”

High‐Throughput Screening of Metabolic Biomarkers and Wearable Biosensors for the Quantification of Metabolites

“…The wearable OECTs cortisol biosensor afforded comparable results with LC-MS/MS measurements in real sweat applications (Figure 6f). [138] Selections and optimizations of micro/nanomaterials decide the capability of OECTs biosensor. The material engineering for OECTs-based biosensor can be considered from the following aspects: 1) Substitutes for metal interconnections; 2) Chemical functionalization or doping of semiconducting polymer; 3) Selective membrane for specific binding.…”

“…[ 137 ] The OECTs‐based biosensor has been adopted for noninvasive detection of urine acid in saliva testing with favorable mechanical compliance and skin‐affinity no matter the changes of skin morphology (Figure 6d). [ 138 ] Meanwhile, OECTs‐based cortisol biosensor would be seamlessly connected to skin in different locations (e.g., arm, forehead, Figure 6e). The wearable OECTs cortisol biosensor afforded comparable results with LC‐MS/MS measurements in real sweat applications (Figure 6f).…”

“…The wearable OECTs cortisol biosensor afforded comparable results with LC‐MS/MS measurements in real sweat applications (Figure 6f). [ 138 ]…”

“…f) Wearable OECTs cortisol biosensor afforded comparable results with LC-MS/MS measurements in real sweat applications. Reproduced with permission [138]. Copyright 2022, American Chemical Society.…”