Integrated multi-material portable 3D-printed platform for electrochemical detection of dopamine and glucose.

3D-printing has become a fundamental part of research in many areas of investigation since it provides rapid and personalized production of parts that meet very specific user needs. Biosensing is not an exception, and production of electrochemical sensors that can detect a variety of redox mediators and biologically relevant molecules has been widely reported. However, most 3Dprinted electrochemical sensors detailed in the literature rely on big, individual, single-material electrodes that require large sample volumes to perform effectively. Our work exploits multi-material fused filament fabrication 3D-printing to produce a compact electrochemical sensor. The device features a built-in well with a volume of approximately 100 μL where the sample is deposited and analyzed via cyclic voltammetry, differential pulse voltammetry, and chronoamperometry to assess sensor performance and sensitivity. The integrated 3D-printed platform successfully detects electrochemical activity for hexaammineruthenium (III) chloride and potassium ferricyanide (0.1 mM to 2 mM in 100 mM KCl), dopamine (50 μM to 1 mM in 1xPBS), and glucose via mediator-free and mediated amperometric glucose oxidase enzyme-based sensors (1 mM to 12 mM in 1xPBS), indicating good acceptance of biological modification. These results reveal the exciting potential of multi-material 3D-printing and how it can be used for the rapid development of efficient, small, integrated, personalized electrochemical biosensors.