All-in-One Single-Print Additively Manufactured Electroanalytical Sensing Platforms

Abstract

This manuscript provides the first report of a fully additively manufactured (AM) electrochemical cell printed all-in-one, where all the electrodes and cell are printed as one, requiring no postassembly or external electrodes. The three-electrode cell is printed using a standard non-conductive poly(lactic acid) (PLA)-based filament for the body and commercially available conductive carbon black/PLA (CB/ PLA, ProtoPasta) for the three electrodes (working, counter, and reference; WE, CE, and RE, respectively). The electrochemical performance of the cell is evaluated first against the well-known nearideal outer-sphere redox probe hexaamineruthenium(III) chloride (RuHex), showing that the cell performs well using an AM electrode as the pseudo-RE. Electrochemical activation of the WE via chronoamperometry and NaOH provides enhanced electrochemical performances toward outer-sphere probes and for electroanalytical performance. It is shown that this activation can be completed using either an external commercial Ag|AgCl RE or through simply using the internal AM CB/PLA pseudo-RE and CE. This all-inone electrochemical cell (AIOEC) was applied toward the well-known detection of ascorbic acid (AA) and acetaminophen (ACOP), achieving linear trends with limits of detection (LODs) of 13.6 ± 1.9 and 4.5 ± 0.9 μM, respectively. The determination of AA and ACOP in real samples from over-the-counter effervescent tablets was explored, and when analyzed individually, recoveries of 102.9 and 100.6% were achieved against UV−vis standards, respectively. Simultaneous detection of both targets was also achieved through detection in the same sample exhibiting 149.75 and 81.35% recoveries for AA and ACOP, respectively. These values differing from the originals are likely due to electrode fouling due to the AA oxidation being a surface-controlled process. The cell design produced herein is easily tunable toward different sample volumes or container shapes for various applications among aqueous electroanalytical sensing; however, it is a simple example of the capabilities of this manufacturing method. This work illustrates the next step in research synergising AM and electrochemistry, producing operational electrochemical sensing platforms in a single print, with no assembly and no requirements for exterior or commercial electrodes. Due to the flexibility, low-waste, and rapid prototyping of AM, there is scope for this work to be able to span and impact a plethora of research areas.

The effect of water ingress on additively manufactured electrodes

“…However, a caveat to this is that in this work whole parts were subjected to immersion rather than the electroactive area alone, as has been the case in previous literature. 24 The change in AME resistance would reasonably be expected to scale with the extent of ingress, so water ingress into a relatively small area of a relatively large electrode should cause a relatively lower increase in resistance than ingress into the whole electrode area. Ultimately, therefore, ingress might prove only a minor concern for electrochemists who limit contact of their AME with water to only a small area.…”

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

“…For example, the detection or quantification of commonly used redox species is widely demonstrated, covering both inner-and outer-sphere electron transfer reactions that show sensor performance and surface sensitivity. 11,19 Biologically relevant molecules such as glucose or dopamine have also been targeted to directly showcase that FFF has the potential to produce fully personalized biosensors 20,21 with sensitivities in the range of 0.01-0.8 µmol L −1 in dopamine 22,23 and 2.4-36.4 µmol L −1 for glucose, 15,24 and in the case of glucose, ruthenium-based mediators have been employed to ease detection and improve sensitivity. [25][26][27][28][29] These 3D-printed biosensors possess a range of limitations that include: (i) their size, with electrodes up to 10 mm in diameter and several millimeters in thickness, 8,12 (ii) the associated large sample volumes that these dimensions require, 8,12,[30][31][32] and (iii) the restriction of the use of 3D-printing to produce only the working electrode, requiring the use of external counter and reference electrodes that complicate experimental setup and use.…”

Additively Manufactured Rotating Disk Electrodes and Experimental Setup

“…AM (particularly FFF/FDM) has been applied to electrochemistry, 6 with the research predominantly focused on the development and use of conductive materials for applications in the fields of energy storage 7 − 9 and sensing. 10 − 12 This area of research started with the production of “lollipop” electrodes from commercially available filament and has progressed into full electrochemical cells with embedded electrodes 13 and the development of bespoke filaments. 14 , 15 Additionally, there is a large amount of research being done to improve the sustainability of AM, through the recycling of used prints or reuse of other polymers into FFF printable filaments.…”

“…AM (particularly FFF/FDM) has been applied to electrochemistry, with the research predominantly focused on the development and use of conductive materials for applications in the fields of energy storage − and sensing. − This area of research started with the production of “lollipop” electrodes from commercially available filament and has progressed into full electrochemical cells with embedded electrodes and the development of bespoke filaments. , Additionally, there is a large amount of research being done to improve the sustainability of AM, through the recycling of used prints or reuse of other polymers into FFF printable filaments. , The entry cost barrier for electrochemical equipment can be vastly reduced through the use of localized additive manufacture, as shown by previous research into the production of cells, electrodes, and accessories for the electrochemical lab, which showed various low-cost AM equipment, such as a screen-printed electrode (SPE) connector, in which it was notably cheaper to buy a 3D printer and produce the SPE holder for less cost than a single commercial SPE holder.…”