Salivary Glucose Detection with Laser Induced Graphene/AgNPs Non-Enzymatic Sensor

Portable glucose sensing analysis based on laser-induced graphene composite electrode

In this work, a portable electrochemical glucose sensor was studied based on a laser-induced graphene (LIG) composite electrode. A flexible graphene electrode was prepared using LIG technology. Poly(3,4-ethylene dioxythiophene) (PEDOT) and gold nanoparticles (Au NPs) were deposited on the electrode surface by potentiostatic deposition to obtain a composite electrode with good conductivity and stability. Glucose oxidase (GOx) was then immobilized using glutaraldehyde (GA) to create an LIG/PEDOT/Au/GOx micro-sensing interface. The concentration of glucose solution is directly related to the current value by chronoamperometry. Results show that the sensor based on the LIG/PEDOT/Au/GOx flexible electrode can detect glucose solutions within a concentration range of 0.5 × 10-5 to 2.5 × 10-3 mol L-1. The modified LIG electrode provides the resulting glucose sensor with an excellent sensitivity of 341.67 μA mM-1 cm-2 and an ultra-low limit of detection (S/N = 3) of 0.2 × 10-5 mol L-1. The prepared sensor exhibits high sensitivity, stability, and selectivity, making it suitable for analyzing biological fluid samples. The composite electrode is user-friendly, and can be built into a portable biosensor device through smartphone detection. Thus, the developed sensor has the potential to be applied in point-of-care platforms such as environmental monitoring, public health, and food safety.