Electrochemical sensor based on laser-induced graphene and CeO₂ for sensitive and selective dopamine detection

In this study, we developed a highly sensitive electrochemical sensor for detecting dopamine (DA) using a simple and fast CO₂ laser scribing technique. The UV/Ozone-treated polyimide (PI) film coated with CeO₂ precursor was scribed by the CO₂ laser to synthesize the electrochemical sensor (UV-LC). The CeO₂ particles were well anchored on the laser-induced graphene (LIG) surface, enhancing the electrochemical surface area (ESA) from 1.31 cm² in LIG to 3.35 cm² in UV-LC. Also, the CeO₂ particles were affected by the reducing charge transfer resistance (R_ct) from 1281 Ω to 761.8 Ω which is the LIG and UV-LC value, respectively. UV-LC demonstrated a linear response to DA concentrations from 0 to 10 μM, with a sensitivity of 25.09 μA/μM·cm² and a detection limit (LOD) of 0.38 μM which is the higher and lower value compared to other metal oxide-based DA sensors. Additionally, UV-LC exhibited good selectivity with glucose (GU), ascorbic acid (AA), and uric acid (UA) being less than 55 % of the DA current response. These results suggest this sensor is highly suitable for DA detection in biosensing applications. Furthermore, this simple and rapid fabrication process opens possibilities for various electrochemical devices.