3D Printed Platform for Impedimetric Sensing of Liquids and Microfluidic Channels

Abstract

Fused deposition modeling 3D printing (FDM-3DP) employing electrically conductive filaments has recently been recognized as an exceptionally attractive tool for the manufacture of sensing devices. However, capabilities of 3DP electrodes to measure electric properties of materials have not yet been explored. To bridge this gap, we employ bimaterial FDM-3DP combining electrically conductive and insulating filaments to build an integrated platform for sensing conductivity and permittivity of liquids by impedance measurements. The functionality of the device is demonstrated by measuring conductivity of aqueous potassium chloride solution and bottled water samples and permittivity of water, ethanol, and their mixtures. We further implement an original idea of applying impedance measurements to investigate dimensions of 3DP channels as base structures of microfluidic devices, complemented by their optical microscopic analysis. We demonstrate that FDM-3DP allows the manufacture of microchannels of width down to 80 μm.

Engineering Biosensors and Biomedical Detection Devices from 3D-Printed Technology

“…The following year, Scott Crump established Stratasys, and FDM molding technology was patented by Stratasys. 55,56 In 1992, the first 3D printing product based on FDM technology was sold. The principle of FDM is to melt the filamentous hot melt material and push it out through a tiny nozzle.…”

Print–Pause–Print Fabrication of Tailored Electrochemical Microfluidic Devices

“…7−11 To that end, one nozzle prints a regular nonconductive thermoplastic, while the other nozzle is loaded with a conductive filament. Conductive filaments are composites made of a thermoplastic matrix, especially PLA, doped with carbon materials such as graphene (PLA-G), 12,13 carbon nanotubes (PLA-CNT), 14,15 or carbon black (PLA-CB). 8,16 However, those conductive filaments are not intended to produce ready-to-use electrochemical sensors but rather conductive tracks for low-voltage circuitry 17,18 or conductivity sensing.…”

“…8,16 However, those conductive filaments are not intended to produce ready-to-use electrochemical sensors but rather conductive tracks for low-voltage circuitry 17,18 or conductivity sensing. 14,15 To use these filaments for chemical sensing applications, they need to be activated to remove thermoplastic from the surface and overexpose the conductive material. There are plenty of postprinting activation procedures described in the literature that provided satisfactory results, such as chemical, 19 electrochemical, 20 sanding, 21 oxygen plasma, 22 laser ablation, 23 or thermal annealing 24 and combinations of them.…”

“…Additive manufacturing is a set of fabrication technologies that are revolutionizing the traditional microfluidics fabrication workflow and bringing unprecedented freedom and complexity of design. − In particular, for electroanalytical devices, it is becoming popular to employ multimaterial fusion filament fabrication (FFF) to construct electrochemical sensing devices. − To that end, one nozzle prints a regular nonconductive thermoplastic, while the other nozzle is loaded with a conductive filament. Conductive filaments are composites made of a thermoplastic matrix, especially PLA, doped with carbon materials such as graphene (PLA-G), , carbon nanotubes (PLA-CNT), , or carbon black (PLA-CB). , …”

Rapid Assessment of Antibiotic Susceptibility Using a Fully 3dprinted Impedance-Based Biosensor

“…One of the few limitations of using this approach is that EIS studies are traditionally performed using commercially-available screen-printed electrodes (SPEs), which offer a number of advantages over conventional diagnostics tools, but also have a set of disadvantages such as a non-customisable design, cost-inefficient large production, and their long-term use may be sparse especially in resource-limited settings. Several groups have addressed this issue by 3D-printing their own diagnosis and analysis systems, but most of them still rely on commercially-available SPEs, overnight cultured samples, and/or use traditional analytical tools (Brosel-Oliu et al, 2019a;Ramiah Rajasekaran et al, 2020;Rengaraj et al, 2018;Sebechlebská et al, 2022;Siller et al, 2020). Further exploitation of 3D-printing and production of personalised electrodes using conductive materials has already proved to be highly useful to develop various electrochemical devices.…”