A low-cost and disposable graphene polylactic (G-PLA) 3D-printed electrode modified with gold particles (AuPs) was explored to detect the cDNA of SARS-CoV-2 and creatinine, a potential biomarker for COVID-19. For that, a simple, non-enzymatic electrochemical sensor, based on a Au-modified G-PLA platform was applied. The AuPs deposited on the electrode were involved in a complexation reaction with creatinine, resulting in a decrease in the analytical response, and thus providing a fast and simple electroanalytical device. Physicochemical characterizations were performed by SEM, EIS, FTIR, and cyclic voltammetry. Square wave voltammetry was employed for the creatinine detection, and the sensor presented a linear response with a detection limit of 0.016 mmol L⁻¹. Finally, a biosensor for the detection of SARS-CoV-2 was developed based on the immobilization of a capture sequence of the viral cDNA upon the Au-modified 3D-printed electrode. The concentration, immobilization time, and hybridization time were evaluated in presence of the DNA target, resulting in a biosensor with rapid and low-cost analysis, capable of sensing the cDNA of the virus with a good limit of detection (0.30 µmol L⁻¹), and high sensitivity (0.583 µA µmol⁻¹ L). Reproducible results were obtained (RSD = 1.14%, n = 3), attesting to the potentiality of 3D-printed platforms for the production of biosensors.

The technology of 3D printing, particularly fused deposition modeling (FDM) 3D printing, has revolutionized the development of electrochemical biosensors, offering a versatile and cost-effective approach for clinical applications. This review explores the integration of FDM in fabricating biosensing platforms tailored for clinical diagnostics, emphasizing its role in detecting various biomarkers and viral pathogens. Advances in 3D printing materials, especially the emergence of bespoke conductive filaments, have allowed the production of highly customizable and efficient biosensors. A detailed discussion focuses on the design and application of these biosensors for viral detection, highlighting their potential to improve diagnostic accuracy. Furthermore, the review addresses current trends, including the push towards miniaturization and multianalyte detection, alongside challenges such as material optimization and regulatory hurdles. By providing a comprehensive overview, this work underscores the transformative impact of 3D-printed electrochemical biosensors in clinical diagnostics while also identifying critical areas for future research and development.

Herein, we present the first 3D-printed electrochemical portable biodevice for the detection of monkeypox virus (MKPV). The electrochemical device consists of two biosensors: an immunosensor and a genosensor specifically designed for the detection of the protein A29 and a target DNA of MKPV, respectively. The electrodes were manufactured using lab-made ultraflexible conductive filaments composed of carbon black, recycled PLA from coffee pods, and castor oil as a plasticizer. The sensors created through 3D printing technology exhibited good reproducibility and repeatability of analytical responses. Furthermore, both the immunosensor and genosensor demonstrated excellent MKPV detection capabilities, with a linear range from 0.01 to 1.0 μmol L^-1 for the antigen and 0.1 to 20.0 μmol L^-1 for the DNA target. The biosensors achieved limits of detection of 2.7 and 29 nmol L^-1 for the immunosensor and genosensor, respectively. Interference tests conducted with the biosensors demonstrated their selectivity for MKPV. Moreover, analyses of fortified human serum samples showed recoveries close to 100%, confirming the absence of significant matrix effects for MKPV analysis. Therefore, the 3D-printed multiplex device represents a viable and highly promising alternative for on-site, portable, and rapid point-of-care MKPV monitoring.