# Adaptive Fabrication of Electrochemical Chips with a Paste-Dispensing 3D Printer

## TL;DR

A new 3D printing method using paste allows for maskless fabrication of electrochemical chips that can detect heavy metals efficiently.

## Contribution

A novel 3D printing technique for fabricating electrochemical chips without masks, using paste dispensing and process optimization.

## Key findings

- Electrochemical chips fabricated using 3D printed paste showed good reversibility in redox reactions.
- The chips reliably detected Pb(II) and Cd(II) ions in solutions using voltammetry.
- Engineering challenges like clogging and dripping were resolved through material and process optimization.

## Abstract

Electrochemical (EC) detection is a powerful tool supporting simple, low-cost, and rapid analysis. Although screen printing is commonly used to mass fabricate disposable EC chips, its mask is relatively expensive. In this research, we demonstrated a method for fabricating three-electrode EC chips using 3D printing of relatively high-viscosity paste. The electrodes consisted of two layers, with carbon paste printed over silver/silver chloride paste, and the printed EC chips were baked at 70 °C for 1 h. Engineering challenges such as bulging of the tubing, clogging of the nozzle, dripping, and local accumulation of paste were solved by material selection for the tube and nozzle, and process optimization in 3D printing. The EC chips demonstrated good reversibility in redox reactions through cyclic voltammetry tests, and reliably detected heavy metal ions Pb(II) and Cd(II) in solutions using differential pulse anodic stripping voltammetry measurements. The results indicate that by optimizing the 3D printing of paste, EC chips can be obtained by maskless and flexible 3D printing techniques in lieu of screen printing.