A 3-D-Printed Integrated PCB-Based Electrochemical Sensor System

In this paper, we report a fully 3-D-printed, flexible, amperometric lactate sensor system with a 3-D-printed, integrated electrochemical circuit platform, a so-called potentiostat, realized via a novel 3-D printing method. First, a lactate sensor was designed in a three-electrode configuration with a layer of deposited enzyme on the conductive silver electrodes. The thin silver electrodes were printed on a flexible substrate. Second, a highly integrated potentiostat circuit prototype was designed and printed on a rigid epoxy board. Both sensor electrodes and printed circuit board (PCB) were fabricated using a novel direct ink writing (DIW) technology with highly viscous silver nanoparticle ink. The fully 3-D-printed potentiostat system along with the sensor demonstrated reliable lactate detection for concentrations in the range of 0-20 mM. The purely additive manufacturing strategy of DIW demonstrated the capability of 3-D printing double-sided circuits with high-density chip-on-board designs as well as the ability to significantly reduce the lead time of PCB prototyping. The 3-D-printed electrochemical sensor system is suitable for wearable devices for continuous monitoring of human metabolisms.