New insights combining paper-based electrochemical biosensing and 3D printing for COVID-19 detection in biological fluids

Abstract

The COVID-19 pandemic outbreak has raised awareness of the importance of developing and making available low-cost, reliable, portable, and disposable diagnostic tests. These characteristics are especially relevant when considering resource-limited locations or developing countries. Access to a laboratory infrastructure with sophisticated equipment and reagents is expensive. They are usually found in urban centers, making access difficult for people who live far from those locations. PCR (polymerase chain reaction) and ELISA (enzyme-linked immunosorbent assay) are the most used techniques to diagnose viral diseases. Specifically, in coronaviruses, the standard gold method is RT-PCR (reverse transcriptase-polymerase chain reaction), which is based on detecting the viral nucleic acid of SARS-CoV-2 in the patient's nose or throat fluids. Diagnostic tests that present rapid-response, are low-cost, ensure adequate accuracy and can be performed wherever the patient is, needs to be developed as alternatives to commercial tests available on the market. In this sense, point-of-care (POC) devices are of great relevance, as they enable the decentralization of various analyses, from clinical diagnosis to environmental monitoring and food safety. Electrochemical detection is one of the most prominent techniques combined with a paper platform for biosensing applications. Therefore, it can provide high sensitivity and selectivity by choosing the suitable electrochemical technique, the electrode materials, the potential interval, the incorporation of recognition elements to analytes, rapid analysis time (in the order of seconds to minutes), and easy operation. The 3D printing approach has been explored as an electrochemical sensor in various applications, including detecting metals in biological and environmental samples. 3D printing or additive manufacturing is a rapid prototyping technology that allows the fabrication/construction of objects with different shapes and materials. Combining paper-based devices and 3D printing is still a field to be explored to develop electrochemical sensors. Considering the new avenues that can be developed by coupling 3D printing and paper platforms, this project aims to print three integrated electrodes using a 3D printer/pen on the paper platform, desiring to use a portable electrochemical sensor to detect COVID-19 in biological fluids.