Copper-nanostructure-modified laser-scribed electrodes based on graphitic carbon for electrochemical detection of dopamine and glucose

BACKGROUND: Carbon-based nanostructures have been attracting major interest in many research fields, including chemical and biological sensing, because of their unique structural dimensions and excellent physical, chemical and mechanical properties. A recently developed laser scribing approach allows design and fabrication of flexible, graphitic carbon-based substrates for (bio-)electrochemical applications, as it provides highly robust and low-cost sensing platforms. RESULTS: Here we demonstrate the fabrication of a highly reproducible laser-scribed graphitic electrode (LSE) on a polyimide (Kapton) film using a simple, do-it-yourself laser engraving system equipped with a 405 nm wavelength laser. Copper nanostructures were deposited onto an electrode surface via the electrodeposition process. The developed three-dimensional graphitic electrodes modified by nano copper/copper oxide species (LSE-Cu) were used for the detection of dopamine and glucose. Electrochemical studies of LSE-Cu showed that in the presence of nano-copper there is an apparent shift of the oxidation peaks of dopamine and ascorbic acid, allowing determination of dopamine without an interference effect, with an excellent sensitivity of 1321.54 μA L mmol⁻¹ cm⁻². Furthermore, the LSE-Cu sensor exhibited highly satisfying analytical performance towards glucose electro-oxidation, with a reproducibility of 5.47% (RSD %). CONCLUSION: We have demonstrated a simple design, fabrication and passivation route for the preparation of LSEs performing as biosensors. Such a cost-effective and design-flexible system is highly suitable for developing a biosensing platform towards various target analytes and further miniaturization of the electrode.