Non-invasive electrochemical immunosensor for sweat cortisol based on L-cys/AuNPs/ MXene modified thread electrode

• Published in: Biosensors & bioelectronics 2022-05, Vol.203, p.114039-114039, Article 114039
• Main Authors: Laochai, Thidarut, Yukird, Jutiporn, Promphet, Nadtinan, Qin, Jiaqian, Chailapakul, Orawon, Rodthongkum, Nadnudda
• Format: Article
• Language: English
• Subjects: Adrenal gland disorder; Biosensing Techniques; Electrochemical Techniques - methods; Electrodes; Gold; Gold nanoparticle; Hydrocortisone; Immunoassay - methods; Limit of Detection; Metal Nanoparticles; MXene; Reproducibility of Results; Sweat; Sweat cortisol; Thread-based electrochemical immunosensor
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2022.114039

Thread-based electrochemical immunosensor is fabricated for non-invasive detection of cortisol in sweat by immobilization of anti-cortisol on L-cys/AuNPs/MXene modified conductive thread electrode. MXene and AuNPs increase the surface area of conductive thread electrode and facilitate anti-cortisol immobilization leading to enhanced sensor sensitivity. Anti-cortisol is immobilized on L-cys/AuNPs/MXene modified electrode by using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysulfosuccinimide coupling agents. The electrochemical detection of cortisol is based on the decrease of oxidation current towards the antigen-antibody binding interaction owing to blocking of electron transfer process by cortisol. Under the optimal conditions, this immunosensor offers high sensitivity, a wide linearity of 5–180 ng mL−1 and a detection limit of 0.54 ng mL−1 with negligible effect from interferences. Furthermore, this immunosensor provides high reproducibility and long-term storage stability (≥6 weeks). Ultimately, this system is successfully applied for the detection of cortisol in artificial sweat with satisfactory results. Hence, this platform might be suitable to apply as a wearable electrochemical sensor for sweat cortisol by integrating on a wristband. [Display omitted] •Label-free electrochemical immunosensor based on L-cys/AuNPs/MXene modified thread electrode is created for cortisol.•AuNPs/MXene increases the specific surface area antibody immobilization leading to increased sensitivity.•This immunosensor offers a wide linearity covering a cut-off cortisol level with high sensitivity.•This platform is successfully applied for cortisol detection in sweat.