Glucocorticoid replacement in Addison disease

Wearable Cortisol Aptasensor for Simple and Rapid Real-Time Monitoring

The necessity of managing stress levels is becoming increasingly apparent as the world suffers from different kinds of stresses including the extent of pandemic, the corona virus disease 2019 (COVID-19). Cortisol, a clinically confirmed stress hormone related to depression and anxiety, affects individuals mentally and physically. However, current cortisol monitoring methods require expert personnel, large and complex machines, and long time for data analysis. Here, we present a flexible and wearable cortisol aptasensor for simple and rapid cortisol real-time monitoring. The sensing channel was produced by electrospinning conducting polyacrylonitrile (PAN) nanofibers (NFs) and subsequent vapor deposition of carboxylated poly(3,4-ethylenedioxythiophene) (PEDOT). The conjugation of the cortisol aptamer on the PEDOT-PAN NFs provided the critical sensing mechanism for the target molecule. The sensing test was performed with a liquid-ion gated field-effect transistor (FET) on a polyester (polyethylene terepthalate). The sensor performance showed a detection limit of 10 pM (<5 s) and high selectivity in the presence of interference materials at 100 times higher concentrations. The practical usage and real-time monitoring of the cortisol aptasensor with a liquid-ion gated FET system was demonstrated by successful transfer to the swab and the skin. In addition, the real-time monitoring of actual sweat by applying the cortisol aptasensor was also successful since the aptasensor was able to detect cortisol approximately 1 nM from actual sweat in a few minutes. This wearable biosensor platform supports the possibility of further application and on-site monitoring for changes of other numerous biomarkers.

Ultrasensitive Stress Biomarker Detection Using Polypyrrole Nanotube Coupled to a Field-Effect Transistor

Stress biomarkers such as hormones and neurotransmitters in bodily fluids can indicate an individual’s physical and mental state, as well as influence their quality of life and health. Thus, sensitive and rapid detection of stress biomarkers (e.g., cortisol) is important for management of various diseases with harmful symptoms, including post-traumatic stress disorder and depression. Here, we describe rapid and sensitive cortisol detection based on a conducting polymer (CP) nanotube (NT) field-effect transistor (FET) platform. The synthesized polypyrrole (PPy) NT was functionalized with the cortisol antibody immunoglobulin G (IgG) for the sensitive and specific detection of cortisol hormone. The anti-cortisol IgG was covalently attached to a basal plane of PPy NT through an amide bond between the carboxyl group of PPy NT and the amino group of anti-cortisol IgG. The resulting field-effect transistor-type biosensor was utilized to evaluate various cortisol concentrations. Cortisol was sensitively measured to a detection limit of 2.7 × 10⁻¹⁰ M (100 pg/mL), with a dynamic range of 2.7 × 10⁻¹⁰ to 10⁻⁷ M; it exhibited rapid responses (<5 s). We believe that our approach can serve as an alternative to time-consuming and labor-intensive health questionnaires; it can also be used for diagnosis of underlying stress-related disorders.