Disposable glutamate biosensor based on platinum nanoparticles, carbon quantum dots and poly-L-aspartic acid

Area of Science:

• Electrochemistry
• Biosensor Technology
• Biochemistry

Background:

• L-glutamate is a crucial neurotransmitter implicated in various neurological functions and disorders.
• Accurate and rapid determination of L-glutamate is essential for clinical diagnostics and research.
• Existing methods for L-glutamate detection can be complex, time-consuming, or require specialized equipment.

Purpose of the Study:

• To design and develop a novel disposable amperometric biosensor for the quantitative determination of L-glutamate.
• To optimize the biosensor's composition and performance for enhanced sensitivity and reliability.
• To validate the biosensor's efficacy in analyzing L-glutamate levels in biological samples like serum.

Main Methods:

• Immobilization of glutamate oxidase (GlOx) onto a screen-printed carbon electrode (SPE) modified with poly-L-Aspartic acid (PAsp), carbon quantum dots (CQD), and platinum nanoparticles (PtNP).
• Optimization of surface composition using the one variable at a time method.
• Characterization of biosensor morphology via scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).
• Electrochemical behavior analysis using cyclic voltammetry (CV).

Main Results:

• The optimized GlOx/PtNP/CQD/PAsp/SPE biosensor demonstrated a linear working range of 1.0–140 µM for L-glutamate.
• A low detection limit of 0.3 µM and a sensitivity of 0.002 µA µM⁻¹ were achieved.
• The biosensor exhibited good measurement repeatability and high analytical recovery (98.9% ± 3.9%) in spiked serum samples.

Conclusions:

• The developed disposable amperometric biosensor offers a sensitive, repeatable, and reliable method for L-glutamate determination.
• The combination of PAsp, CQD, and PtNP significantly enhances the biosensor's performance.
• This biosensor shows great potential for practical applications in clinical diagnostics and biomedical research for monitoring L-glutamate levels.