Single-step fabrication of electrochemical flow cells utilizing multi-material 3D printing

Here we present methodology for fabricating electrochemical flow cells with embedded carbon-composite electrodes in a single step using simultaneous 3D printing of insulating poly(lactic acid) (PLA) and a commercially available graphene–PLA composite. This work is significant because it is the first demonstration that devices capable of fluid handling and electrochemical sensing can be produced in a single fabrication step using inexpensive equipment. We demonstrate the broad utility of this approach using a channel-flow configuration as an exemplary system for hydrodynamic electrochemistry. Unmodified devices were characterized using hydrodynamic electrochemistry, and behave according to the well-established Levich equation. We also characterized the fabrication reproducibility and found that the devices were within 3% RSD. The 3D-printed sensors we employed were subsequently modified by electroplating Au and used under flowing conditions to detect catechol, whose oxidation requires two electrons and two protons and is thus more challenging to analyze than the outer-sphere FcCH ₂ OH. We envision these results will pave the way for the development of highly customized micro-total analysis systems that include embedded electrochemical sensors for a variety of redox-active analytes.