3D printed microfluidic devices with integrated versatile and reusable electrodes

Abstract

We report two 3D printed devices that can be used for electrochemical detection. In both cases, the electrode is housed in commercially available, polymer-based fittings so that the various electrode materials (platinum, platinum black, carbon, gold, silver) can be easily added to a threaded receiving port printed on the device; this enables a module-like approach to the experimental design, where the electrodes are removable and can be easily repolished for reuse after exposure to biological samples. The first printed device represents a microfluidic platform with a 500 × 500 μm channel and a threaded receiving port to allow integration of either polyetheretherketone (PEEK) nut-encased glassy carbon or platinum black (Pt-black) electrodes for dopamine and nitric oxide (NO) detection, respectively. The embedded 1 mm glassy carbon electrode had a limit of detection (LOD) of 500 nM for dopamine and a linear response (R2= 0.99) for concentrations between 25-500 μM. When the glassy carbon electrode was coated with 0.05% Nafion, significant exclusion of nitrite was observed when compared to signal obtained from equimolar injections of dopamine. When using flow injection analysis with a Pt/Pt-black electrode and standards derived from NO gas, a linear correlation (R2 = 0.99) over a wide range of concentrations (7.6 - 190 μM) was obtained, with the LOD for NO being 1 μM. The second application showcases a 3D printed fluidic device that allows collection of the biologically relevant analyte adenosine triphosphate (ATP) while simultaneously measuring the release stimulus (reduced oxygen concentration). The hypoxic sample (4.76 ± 0.53 ppm oxygen) released 2.37 ± 0.37 times more ATP than the normoxic sample (8.22 ± 0.60 ppm oxygen). Importantly, the results reported here verify the reproducible and transferable nature of using 3D printing as a fabrication technique, as devices and electrodes were moved between labs multiple times during completion of the study.

Design and additive manufacture for flow chemistry

“…126 In both cases the devices were printed in a modular fashion, whereby the electrodes could be easily removed and replaced via a threaded receiving port printed onto the device. The first device represented a 0.5 mm square microfluidic platform, with ports for integration with glassy carbon or platinum black electrodes.…”

Additive Manufacturing for Electrochemical (Micro)Fluidic Platforms

“…The same flow cell has also been employed for trace FIA-EC analysis of dissolved hydrogen sulphide. 61 Other groups have also developed CFE 62 and WJE 63 flow cells using AM. One advantage of the AM approach, as shown above, is that designs can be readily altered and that even in one build, several different structures can be fabricated.…”

Embedding objects during 3D printing to add new functionalities

“…20,21 In addition, with a proper device design, accessories can be assembled to the 3D printed devices after they are built/printed so that additional functions can be added to the 3D printed devices. 7,18,[22][23][24] Furthermore, direct multi-material 3D printing using different polymers, e.g., soft and rigid polymers, from a 3D CAD model has also been demonstrated. 25 Clearly, the unique method of printing 3D structures could have huge potential and competitive advantages over the traditional fabrication or manufacturing processes.…”

“…[1][2][3][4][5] Also, device designs can be easily generated, modified, and shared using CAD programs, and then conveniently ordered using a 3D printing mail-order service with device cost precisely predicted via a web interface. 6 For example, applications in the areas of electrochemical detection, 7,8 reconfigurable modular systems, 9-12 microfluidic automation and valving, [13][14][15] pathogenic bacteria detection, 16,17 drug transport and cell a) E-mail: yuenp@corning.com. Tel.…”