# MICRO (Multimaterial, Integrated, Compact, Ready-to-Plug, One-Step 3D-Printed): A Simple-to-Use Electrochemical Device for On-Site Analysis and Drug Screening

## TL;DR

This paper introduces a 3D-printed electrochemical device that is easy to use, portable, and low-cost for on-site analysis and drug screening.

## Contribution

The novel contribution is a ready-to-plug, one-step 3D-printed electrochemical cell with integrated components and USB connectivity.

## Key findings

- The device showed performance comparable to commercial electrodes for detecting model analytes.
- It successfully detected anabolic steroid oxymetholone in seized samples with high accuracy.
- The device is cost-effective (<ten cents) and suitable for on-site forensic analysis.

## Abstract

3D printing has emerged as a transformative technology
in electroanalytical
chemistry, enabling the rapid, low-cost, and reproducible mass fabrication
of portable devices and sensors for several areas such as environmental,
clinical, food, and forensic applications. Herein, we present a multimaterial,
integrated, compact, ready-to-plug, and one-step additively manufactured
electrochemical cell (MICRO-EC3D). This all-in-one device
was fabricated using a dual-extruder 3D printer and comprises a single
unit containing the three electrodes/tracks (conductive carbon black–polylactic
acid, CB-PLA) as well as the body containing an embedded mini solution
reservoir (polyethylene terephthalate glycol, PETG). This arrangement
eliminates the assembling of external accessories and allows the introduction
of miniaturized stirrers. Unlike previous similar 3D-printed devices,
the proposed microcell is readily interfaced to mobile apparatus (hand-held
potentiostats and smartphones) through user-friendly USB-based connectors
(wireless, crocodile clip, or banana pin). After a quick chemical
(immersion in 5.0 M NaOH for 3 min) and electrochemical treatment
(+1.4 V for 200 s and −1.0 V for 200 s in 0.5 M NaOH), this
device showed performance comparable to a commercial carbon screen-printed
electrode for model analytes (ferricyanide, paracetamol, and nitrite).
The analytical use of the device was demonstrated for the square-wave
voltammetric detection of anabolic steroid oxymetholone (OXM), in
which two linear responses (1.0 to 5.0 and 6.0 to 10.0 μM; R
2 > 0.99) and a limit of detection of 0.21
μM
were obtained. These values were suitable for the screening of OXM
in three seized samples, yielding results consistent with gas chromatography–mass
spectrometry. These findings evidence the potential of MICRO-EC3D as an easy-to-use, portable, and low-cost (<ten cents)
tool for on-site preliminary forensic analysis and for increasing
the acceptance and popularity of electrochemical methods, mainly among
inexpert analysts.