Controlling the Inkjet Printing Process for Electrochemical (Bio)Sensors

Inkjet printing is a popular technique for depositing high-precision ink lines. This study reports the printing parameters' influence on the electrical properties of the sensing devices. The electrochemical sensors are fabricated with a commercial piezoelectric printer and silver ink. Different substrates are evaluated in the printing process, including paper, polyimide, and polyvinyl chloride (PVC) tapes. Ink depositions' temperature, ink drop spacing, length, and the number of the ink layer are also evaluated in this study. Higher temperatures (40 degrees C) make the substrate surface smoother, improving the printing quality. Controlling the ink drop spacing produces narrow continuous ink lines. The number of ink layers changes the film thickness, altering their electroactive surface area. The best printing parameters are PVC tape at 40 degrees C, 17 mu m drop spacing, one layer, and 13 mm length. Under optimized conditions, three-electrode electrochemical systems are fully printed with silver ink, showing batch-to-batch reproducibility (RSD = 3%). Their analytical performance is evaluated for picric acid, hydrogen peroxide, and glucose quantification. The sensors are modified with glucose oxidase to quantify glucose in artificial saliva, confirming their analytical applicability. Therefore, this work reports fundamental aspects of inkjet printing, bringing valuable findings to guide new research involving inkjet-printed electrochemical biosensors/sensors ((bio)sensors).