Laser-Induced Graphene on the Surface of Carbon-Coated 3D-Printed Microneedle Array for Minimally Invasive Electrochemical Detection of Olanzapine

Abstract

Background: We have developed a straightforward and scalable fabrication strategy to create laser-induced graphene on the tips of a carbon-coated 3D-printed microneedle array-based wearable electrochemical sensor to detect OZP in interstitial fluid. The device used a 3D-printed customized microneedle array, followed by spray coating of conductive carbon and silver inks to form the working, counter, and reference electrodes. Further, the carbon-coated microneedle array-based working electrode was laser-treated to alter the surface into a graphitic structure for enhanced sensitivity. After physical and electrochemical characterization, the fabricated microneedle sensor was employed for the OZP detection. Results: Under optimized settings, the microneedle sensor exhibited high sensitivity and specificity toward OZP, with a broad linear range of 0.05-500 μM and a lowest limit of detection of 0.0026 μM. The practical applicability was validated by detecting OZP in artificial interstitial fluid while penetrating a skin-like parafilm model and phantom gel matrix, which demonstrated the potential and practicability of the platform for minimally invasive monitoring of antipsychotic drugs. Significance: The obtained results highlight the feasibility of this cost-effective, scalable, and minimally invasive microneedle platform for monitoring OZP; this platform can also be readily adapted for the preparation of other wearable biosensors.