Polyimide adhesive tapes as a versatile and disposable substrate to produce CO2 laser-induced carbon sensors for batch and microfluidic analysis

Abstract

The laser scribing technique produced disposable electrochemical devices with Kapton adhesive tape as a polyimide substrate. The approach consisted of carbonizing the polyimide substrate with a CO2 laser source, generating the 3-electrode electrochemical system based on carbon conductive tracks. The materials were characterized by Raman spectroscopy, scanning electron microscopy, and electrochemical techniques. The laser processing parameters were submitted to the optimization process, demonstrating a strong impact on the electrochemical properties of the sensors. The sensors were initially fabricated in a chip format, providing satisfactory electrochemical responses compared to commercial screen-printed electrodes. In addition, they showed reproductivity, repeatability, and storage stability. Once characterized, the sensors were combined with paper devices to show the versatility of the electrochemical system. Paper was chosen because of its ubiquity and ability to generate flow without external pumps, resulting in portable analytical platforms. This combination can be advantageous for point-of-need applications. The analytical performance of the devices was evaluated for voltammetric determination of 3-nitrotyrosine, uric acid, and dopamine, demonstrating attractive features for analytical applications.