Abstract
This study develops a hand-held stress assessment meter with a chemically colorimetric strip for determining salivary α-amylase activity, using a 3,5 dinitrosalicylic acid (DNS) assay to quantify the reducing sugar released from soluble starch via α-amylase hydrolysis. The colorimetric reaction is produced by heating the strip with a mini polyester heater plate at boiling temperature to form a brick red colored product, which measured at 525 nm wavelength. This investigation describes in detail the design, construction, and performance evaluation of a hand-held α-amylase activity colorimeter with a light emitted diode (LED) and photo-detector with built-in filters. The dimensions and mass of the proposed prototype are only 120 × 60 × 60 mm3 and 200 g, respectively. This prototype has an excellent correlation coefficient (>0.995), comparable with a commercial ultraviolet–visible spectroscope, and has a measurable α-amylase activity range of 0.1–1.0 U mL−1. The hand-held device can measure the salivary α-amylase activity with only 5 μL of saliva within 12 min of testing. This sensor platform effectively demonstrates that the level of salivary α-amylase activity increases more significantly than serum cortisol, the other physiological stressor biomarker, under physiologically stressful exercise conditions. Thus, this work demonstrates that the hand-held α-amylase activity meter is an easy to use and cost-effective stress assessment tool for psychoneuroendocrinology research.
Highlights
Stress, stress-related diseases, and stress assessments are critical issues in clinical, psychological, biomedical, and sport medicine research
Our previous work [35] revealed that to digital information feeding into the microprocessor (PC/PDA)
The salivary α-amylase (sAA) activity determined by the proposed system can effectively and quantitatively distinguish physiological stress levels, and avoid the diurnal effect found in serum cortisol
Summary
Stress-related diseases, and stress assessments are critical issues in clinical, psychological, biomedical, and sport medicine research. Certain hormones in saliva, such as cortisol and catecholamines (norepinephrine, NE), that are released from the blood and are found in an unbound free state in saliva, are considered to be good stress biomarkers, and are widely monitored to measure endocrinological stress [2]. This is mainly because saliva sampling is non-invasive and not stressful, and does not require specialized personnel [1]. Salivary catecholamines have concentrations several-fold lower than those of venous blood, and do not reflect the actuate changes in the blood catecholamines released by activation of SAM.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
