Dithiobis(succinimidyl propionate) modified gold microarray electrode based electrochemical immunosensor for ultrasensitive detection of cortisol

Abstract

Gold microelectrode arrays functionalized with Dithiobis(succinimidyl propionate) self-assembled monolayer (SAM) have been used to fabricate an ultrasensitive, disposable, electrochemical cortisol immunosensor. Cortisol specific monoclonal antibody (C-Mab) was covalently immobilized on the surface of gold microelectrode array and the sensors were exposed to solutions with different cortisol concentration. After C-Mab binding, unreacted active groups of DTSP were blocked using ethanol amine (EA) and label-free electrochemical impedance (EIS) technique was used to determine cortisol concentration. EIS results confirmed that EA/C-Mab/DTSP/Au based biosensor can accurately detect cortisol in the range of 1 pM to 100 nM. The biosensor was successfully used for measurement of cortisol in interstitial fluid in-vitro. This research establishes the feasibility of using impedance based biosensor architecture for disposable, wearable cortisol detector.

Electrochemical biosensors for hormone analyses

“…Cortisol is a biomarker for numerous diseases and it has got a vital role for the regulation of blood pressure, glucose levels, and carbohydrate metabolism, within the physiological limit (Vasudev et al, 2013). Arya et al (2010) used gold microelectrode arrays functionalized with dithiobis(succinimidyl propionate) selfassembled monolayer (SAM) to fabricate an ultrasensitive, disposable, electrochemical cortisol immunosensor. They used corticosterone which is very similar in structure to cortisol in a steroid family.…”

Electrochemical sensing method for point-of-care cortisol detection in human immunodeficiency virus-infected patients

“…16 an electrochemical immunosensor is prepared via immobilizing anti-C ab onto an SAM-modified IDE-Au electrode. Stepwise schematic illustration of LTCC-based microfluidic chip.…”

“…[11][12][13] The introduction of nano/microelectrodes, nanostructured sensing materials, microelectronics, and miniaturized sensing transducers in sensor fabrication have been shown to improve device performance. 11,12,[15][16][17][18][19] The integration of a cortisol sensor with a microfluidic system and a miniaturized potentiostat (M-P) has been reported to monitor cortisol with reduced form factors. 11,18,20 Further, efforts are being made to develop these sensing systems at POC levels for personalized health monitoring.…”

“…14,18,[21][22][23] Electrochemical immunosensors based on self-assembled monolayers (SAMs) and nanostructures have been reported to detect cortisol, but their application in real sample analysis is currently limited. [16][17][18] Therefore, there is an urgent need to establish an electrochemical sensing protocol for detecting cortisol in desired fluids, such as plasma, blood, saliva, urine, and interstitial fluid, of patients at the POC.…”

In Situ Bioconjugation and Ambient Surface Modification Using Reactive Charged Droplets

“…present on the biomolecules. [7][8][9][10][11] The formation of amide bonds is one of the most stable and widely executed techniques among bio-conjunction methods, and typically involves the reaction between activated carbonyl carbons and amines. 12 The reaction time for this wet-chemistry based method is, however, long (at least 4 h) and involves three independent steps (scheme 1c): (1) attachment of a bi-functional linker containing thiol and carboxylic acid groups to the gold surface via Au-S bond formation through surface self-assembly chemistry; (2) activation of the terminal carboxylic acid group through EDC (1-ethyl-3-(-3-dimethylaminopropyl) carbodiimide hydrochloride) / NHS (NHydroxysuccinimide) chemistry; and (3) conjugation of the biomolecule through the reaction of the NHSactivated ester moiety (derived from step (2) above) with primary amine groups present in the biomolecule.…”