Speaker
Description
Field-effect transistors (FETs) have attracted interest as primary candidates for the fabrication of state-of-the-art sensor platforms because they can achieve high current amplification with a relatively high signal-to-noise ratio. Importantly, one-dimensional nanomaterials that exhibit high charge carrier mobility along their long axes can be used in highly sensitive biosensors. Among the one-dimensional nanomaterials available, the remarkable physical and chemical characteristics of one-dimensional conducting polymers (CPs) at the nanometer scale provide outstanding sensing performance in biosensor application. Cortisol is a critical glucocorticoid steroid hormone in humans, derived from cholesterol. Moreover, cortisol is a clinically proven stress biomarker that plays a vital role in the regulation of various physiological processes such as blood pressure, glucose levels, and carbohydrate metabolism. Variations or abnormalities in physiological cortisol levels regulate acute and chronic stress responses ; they also differentiate between disease states and thus serve as indicators of progression. 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 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.
References
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| Keywords | Field-effect transistors, Conducting polymers, Nanotube, Polypyrrole |
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