Circular Economy Electrochemistry: Recycling Old Mixed Material Additively Manufactured Sensors into New Electroanalytical Sensing Platforms

Abstract

Recycling used mixed material additively manufactured electroanalytical sensors into new 3D-printing filaments (both conductive and non-conductive) for the production of new sensors is reported herein. Additively manufactured (3D-printed) sensing platforms were transformed into a non-conductive filament for fused filament fabrication through four different methodologies (granulation, ball-milling, solvent mixing, and thermal mixing) with thermal mixing producing the best quality filament, as evidenced by the improved dispersion of fillers throughout the composite. Utilizing this thermal mixing methodology, and without supplementation with the virgin polymer, the filament was able to be cycled twice before failure. This was then used to process old sensors into an electrically conductive filament through the addition of carbon black into the thermal mixing process. Both recycled filaments (conductive and non-conductive) were utilized to produce a new electroanalytical sensing platform, which was tested for the cell's original application of acetaminophen determination. The fully recycled cell matched the electrochemical and electroanalytical performance of the original sensing platform, achieving a sensitivity of 22.4 ± 0.2 μA μM −1 , a limit of detection of 3.2 ± 0.8 μM, and a recovery value of 95 ± 5% when tested using a real pharmaceutical sample. This study represents a paradigm shift in how sustainability and recycling can be utilized within additively manufactured electrochemistry toward promoting circular economy electrochemistry.

Multi-walled carbon nanotubes/carbon black/rPLA for high-performance conductive additive manufacturing filament and the simultaneous detection of acetaminophen and phenylephrine

“…The resistance continued to decrease with increasing amounts of MWCNT; however, the printability of the filament was greatly diminished above 40% MWCNT, with the filament becoming brittle. The MWCNT with CB (10 wt%/15 wt%, 40:60% ratio of MWCNT to CB) filament was therefore chosen and then produced using the same thermal mixing techniques as outlined previously [ 27 , 29 , 33 , 34 ] and represented in Fig. 1 A.…”

Electroanalysis overview: additive manufactured biosensors using fused filament fabrication

“…This facile production would be a huge step toward commercialisation of additive manufactured electrochemical biosensors. This print was also shown to be recyclable, 64 which indicates another area of benefit for additive manufacturing electrochemistry over more established techniques such as screen-printing. The sensing of glucose is a key biosensor target and has continued to be the focus of immense research activity where continuous glucose monitoring can reduce the risks of diabetes induced diseases allowing the diabetics to sustain a healthy lifestyle while precluding the costly and lethal late-stage diabetic complications.…”

Electroanalytical overview: the sensing of carbendazim

“…53 Recently, researchers have begun to design and produce their own conductive filament utilising different loadings and nanomaterials compared to the commercially available options. 54–56 Silva et al 52 took this approach and have reported the design of a fully AM microfluidic platform coupled with a paper-based distribution channel for the sensing of carbendazim within in honey samples. As shown within Fig.…”