SERS-based immunoassay for monitoring cortisol-related disorders

• Published in: Biosensors & bioelectronics 2020-10, Vol.165, p.112418-112418, Article 112418
• Main Authors: Villa, Javier E.L., Garcia, Isabel, Jimenez de Aberasturi, Dorleta, Pavlov, Valeri, Sotomayor, Maria D.P.T., Liz-Marzán, Luis M.
• Format: Article
• Language: English
• Subjects: Biosensing Techniques; Chromatography, Liquid; ELISA; Gold; Humans; Hydrocortisone; Immunoassay; Magnetic separation; Plasmonics; Spectrum Analysis, Raman; Surface-enhanced Raman spectroscopy; Tandem Mass Spectrometry; UPLC-MS
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2020.112418

As a natural response to a stressful situation, the human body produces cortisol. For this reason, cortisol is also called “the stress hormone” and is considered to be the principal stress biomarker. Although cortisol response to stress is essential for survival, abnormal levels in biological fluids may represent serious health risks. In this work, we present a cortisol biosensor which relies on a highly sensitive technique (surface-enhanced Raman spectroscopy, SERS) and a specific recognition (immunoassay). Gold nanostars were used as SERS nanotags, since they provided a better response than nanorods or nanospheres. Using the same concept, two different immunoassay modalities were evaluated, using either magnetic beads or gold-coated glass slides decorated with cortisol antibodies as the capture substrates. The magnetically-assisted SERS immunoassay presented a better performance and was therefore selected to quantify cortisol content in biological fluids (urine and serum). Significant advantages of this assay were found over standard methods such as Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS) and Enzyme-Linked Immunosorbent Assay (ELISA), including higher sensitivity and repeatability, minimum sample preparation, simplicity, and portability. Therefore, the proposed SERS immunoassay might be implemented as a highly efficient tool for in situ monitoring of human stress levels and cortisol-related disorders (e.g. Cushing's syndrome and Addison's disease). Rational design of a surface-enhanced Raman spectroscopy-based biosensor to monitor cortisol in biological fluids. [Display omitted] •A novel cortisol biosensor relies on high sensitivity of SERS and specificity of immunoassay.•SERSI may use either magnetic beads or gold-coated glass slides as the capture substrates.•The magnetically-assisted SERSI was selected to quantify cortisol content in biological fluids (urine and serum).•This assayover-performs standard methods such as UPLC-MS and ELISA.