# Cost-Effective Fabrication of Laser-Induced Graphene Electrochemical Cell for NADH Detection

## TL;DR

Researchers developed a low-cost laser-induced graphene sensor for detecting NADH, a biomarker linked to neurodegenerative diseases.

## Contribution

A cost-effective laser-induced graphene electrochemical cell for sensitive NADH detection is introduced.

## Key findings

- The sensor detected NADH with a limit of detection of 2.72 μmol L–1.
- The sensor exhibited high repeatability with a relative standard deviation of 2.76%.
- Each electrochemical cell cost only U$ 0.10 to produce.

## Abstract

The unique properties and versatile applications of laser-induced
graphene (LIG) have garnered significant interest for electrochemical
sensing technologies. In this study, we report the fabrication and
application of an in-house produced LIG/polyimide (PI) composite,
generated via 450 nm laser irradiation, for the amperometric detection
of Nicotinamide Adenine Dinucleotide (NADH), a critical biomarker
associated with several neurodegenerative human diseases. The LIG
structure was confirmed by Raman spectroscopy, X-ray photoelectron
spectroscopy (XPS), and sheet resistance measurements, with an average
sheet resistance (R
s) of 24.38 ±
2.19 Ω/□, indicating excellent electrical conductivity.
XPS analysis revealed the presence of CO bonds (288.9 eV),
formed under oxidizing conditions during LIG fabrication, which may
contribute to enhanced electrocatalytic activity by facilitating NADH
oxidation through redox mediation. Using a printed Ag/AgCl pseudoreference
electrode and an applied potential of only 50 mV vs Ag/AgCl, NADH
was detected within a concentration range of 5 μmol L–1 to 10 mmol L–1. The sensor exhibited a limit of
detection (LOD) of 2.72 μmol L–1 and a limit
of quantification (LOQ) of 9.07 μmol L–1,
with a linear response up to 1 mmol L–1. The repeatability
of the electrochemical oxidation of NADH resulted in a relative standard
deviation (RSD) of 2.76%, while the reproducibility, evaluated as
intra- and interbatch variability, yielded RSD values of 5.78 and
8.22%, respectively. Furthermore, the total material cost for each
electrochemical cell was estimated at only U$ 0.10, highlighting the
method’s potential for low-cost and environmentally friendly
biosensor development. The fabricated LIG platform offers a promising
route for sensitive, scalable, and sustainable detection of NADH and
potentially other clinically relevant analytes.