Development of a Prototype Lateral Flow Immunoassay of Cortisol in Saliva for Daily Monitoring of Stress

Abstract

Emotional stress negatively affects the quality of a person’s daily life. From a physiological point of view, stress is expressed in the excitation of the hypothalamic–pituitary–adrenal cortex axis, which leads to the release of the hormone cortisol into the blood. We developed a lateral flow immunoassay to detect cortisol in human salivary fluid and tested it on 10 healthy volunteers daily for about one month n = 293 saliva samples). Cortisol was detected in concentrations ranging from 1 to 70 ng/mL. Salivary cortisol levels were confirmed by ELISA. The straightness range of LFIA calibration was from 1 to 100 ng/mL. The diagnostic sensitivity of the method was 73%. It was found that in 3 out of 10 subjects, fluctuations in the level of cortisol in saliva partially corresponded to the subjectively assessed level of stress.

Computational modelling of a competitive immunoassay in lateral flow diagnostic devices

“…7A shows a nonlinear behaviour of the signal obtained for the concentration ranges (1 × 10 −6 to 5 × 10 −4 mol m −3 ) of cortisol considering its presence in clinical samples corresponding to a pathological condition. 28,29 Please note that the signal generated would have a contribution from both the test line and control line, wherein the signal generated on the test line would be inversely proportional to the analyte concentration as we are measuring the signal for a competitive assay in this case. The test line and control line signals were obtained separately from COMSOL simulations and plotted for our references in ESI † S7.…”

Early development of self‐administered COVID‐19 rapid test based on nucleocapsid detection in saliva sample

“…These small AuNPs have a small sur face area for antibody internalization (Byzova et al 2017). Moreover, the AuNP with size 26 ± 6 nm was also used to develop LFIA of cortisol in saliva, which has an analytical sensitivity of 73% (Panfilova 2021).…”

Coupling Capillary-Driven Microfluidics with Lateral Flow Immunoassay for Signal Enhancement

“…However, it can be measured using a less sensitive competitive immunoassay (compared with sandwich immunoassay) [ 11 , 15 ]. Even so, the quantitative measurement using competitive assay mostly has a narrow detectable range, which is more evident in calorimetry, typically with a concentration detection limit of approximately 100 ng/mL [ 16 ]. This limit disrupts salivary quantitative cortisol sensing, considering its low concentration range.…”