A Disposable Printed Liquid Gate Graphene Field Effect Transistor for a Salivary Cortisol Test | JoVE Visualize

A Disposable Printed Liquid Gate Graphene Field Effect Transistor for a Salivary Cortisol Test

¹College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300350, P. R. China.

ACS Sensors|August 4, 2021

View abstract on PubMed

Summary

A new portable sensor using liquid gate graphene field-effect transistors (Lg-GFETs) enables easy, non-invasive salivary cortisol monitoring at home. This device accurately tracks cortisol levels, aiding in understanding circadian rhythms.

Area of Science:

Biomedical Engineering
Materials Science
Analytical Chemistry

Background:

Salivary cortisol monitoring is clinically significant for assessing circadian rhythms.
Current methods for salivary cortisol analysis can be cumbersome and stressful for patients.
Non-invasive, at-home monitoring solutions are highly desirable for both clinicians and patients.

Purpose of the Study:

To develop a portable salivary cortisol test setup for convenient, at-home monitoring.
To utilize a liquid gate graphene field-effect transistor (Lg-GFET) as the core sensing element.
To demonstrate the feasibility of tracking circadian cortisol rhythms using the developed device.

Main Methods:

Graphene ink synthesis via modified liquid exfoliation and Lg-GFET printing using direct-ink-write technology.
Functionalization of Lg-GFETs with tetrakis(4-carboxyphenyl) porphyrin and cortisol aptamer for selective detection.
Evaluation of sensor sensitivity, selectivity, and robustness across a wide concentration range.

Main Results:

The Lg-GFET-based sensor exhibited good linear sensitivity from 0.01 to 10^4 nM.
The sensor demonstrated excellent anti-interference capabilities against structurally similar substances.
Successful conceptual application in tracking the circadian rhythm of salivary cortisol was achieved.

Conclusions:

The flexible Lg-GFET-based platform offers a viable solution for instant salivary cortisol detection.
This technology meets the requirements for at-home salivary cortisol assays.
The developed platform provides a novel approach for creating similar portable medical diagnostic devices.

Keywords:

aptamer