The Development of a Versatile Activation Protocol for Carbon-Infused Thermoplastic-Based 3D Printed Electrochemical Sensors

Point-of-care (POC) diagnostics is rapidly expanding as researchers continually develop advanced sensors and integrated devices with the goal of streamlining on-site detection and analysis. Recently, the utilization of 3D printing for rapid fabrication of housings, electrodes, and sensors for use at the POC has been realized and exploited towards diverse applications. Particularly interesting is the use of 3D printed carbon electrodes (3DpCEs) in POC diagnostics owing to its simplicity, affordability, and mass production capabilities for developing selective and sensitive sensors either for direct use or through post-printing surface modifications. Herein, a comprehensive investigation of an alkaline-assisted electrochemical activation (AAEA) protocol for the fabrication of sensitive and selective 3DpCEs was completed. In this study we explored the influence and effect of basicity, activation cycles, activation time, and scan rate. Following the optimization of the activated 3DpCEs, a comparative study was performed using nonactivated and alkaline immersed 3DpCEs, where AAEA 3DpCEs demonstrated higher current responses, improved reversibility, and significantly increased reproducibility. The AAEA protocol for 3DpCEs also provides a versatile modification protocol for the design of sensors capable of selectively detecting biomolecules in the presence of potential interferents. Using the developed protocol, the AAEA 3DpCEs were applied toward i) the selective separation and sensing of catechol and hydroquinone and ii) the detection of glucose using copper deposited 3DpCEs.