Electrochemical detection of cortisol on graphene quantum dots modified electrodes using a rationally truncated high affinity aptamer

Redox-Concatenated Aptamer Integrated Skin Mimicking Electrochemical Patch for Noninvasive Detection of Cortisol

“…This was done by using the standard deviation of the control sample and the slope of the polynomial equation, aligning closely with the experimentally obtained concentration . The limit of detection for the human sweat assay was found to be lower (the biosensor demonstrated cortisol detection suitable for abnormally high levels in sweat that can be indicative of various physiological conditions such as anxiety disorders and Cushing’s syndrome (>0.4 μM)). , The selected cortisol aptamer has proven to display high specificity against biomolecules with analogous structures to cortisol, such as corticosterone, triamcinolone, and cortisone . We validated the rCA’s specificity with sweat biomolecules such as glucose and lactate that are present in very high concentrations and can possibly interfere with the signal.…”

“…The cortisol-specific aptamer used in this work was based on a previous study on truncated aptamers for cortisol detection. 17 Hydrocortisone CRS was purchased from the European Pharmacopoeia. Potassium hexacyanoferrate(II) trihydrate, magnesium chloride, hexaammine ruthenium(III) chloride 98%, 6-mercapto-1-hexanol 97%, tris(2-carboxyethyl)-phosphine hydrochloride powder, 1.0 M phosphate buffer solution, nuclease free water, lactic acid solution, α-D-glucose, testosterone, progesterone, and 1 M Trizma hydrochloride solution were all purchased from Sigma-Aldrich.…”

“…All of the aptamer sequences were purchased from Integrated DNA Technologies, Inc. (Table S1). The cortisol-specific aptamer used in this work was based on a previous study on truncated aptamers for cortisol detection . Hydrocortisone CRS was purchased from the European Pharmacopoeia.…”

“…43,47 The selected cortisol aptamer has proven to display high specificity against biomolecules with analogous structures to cortisol, such as corticosterone, triamcinolone, and cortisone. 17 We validated the rCA's specificity with sweat biomolecules such as glucose and lactate that are present in very high concentrations and can possibly interfere with the signal. For both biomarkers, the average physiological concentration present in human sweat (lactate, 22.5 mM; glucose, 0.1 mM) and a standard 1 μM concentration were tested to compare with the Captain Patch's response to the cortisol (1 μM) and control (0 μM).…”

“…Cortisol is a steroid hormone, and its physiological level in blood, saliva, and sweat is related to regulating circadian rhythm and key to the stress-responsive hypothalamus–pituitary–adrenal axis in the body . Since the dysregulation of cortisol can lead to major depressive disorder, anxiety disorders, and posttraumatic stress disorder, many efforts have been taken to develop wearable biosensors that can continuously monitor cortisol levels noninvasively. − Electrochemical aptamer-based wearable biosensors are emerging as strong candidates in offering better analytical and clinical performance (sensitivity and specificity) for the noninvasive detection of cortisol . Aptamers, short strands of DNA or RNA, have shown advantages over protein-based biorecognition reagents due to their low cost, stability, and ease of synthesis.…”