Stick-and-test: simple tape-based devices for SARS-CoV-2 isothermal molecular detection

Portable analytical devices have been enabling point-of-care molecular diagnostic applications. However, the laborious preparation of conventional microdevices still limits their broader use, especially in resource-limited settings in microinstrumentation. Here, we describe an alternative fabrication process that allows the production of low-cost disposable devices based on double-sided adhesive tape and polyester film (DST-Pe). The applicability of the DST-Pe-based device was demonstrated across molecular diagnostic steps from nucleic acid extraction to detection and result reading for SARS-CoV-2 detection. The device was shown to be able to isolate RNA by dynamic solid-phase extraction (dSPE) from samples of patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with good repeatability and an efficiency of 56.81%. The reverse transcription loop-mediated isothermal amplification (RT-LAMP) of SARS-CoV-2 RNA was performed in 30 min with a sensitivity of 10 copies μL^-1. The optical transparency of the DST-Pe devices allowed visual detection with the naked eye by adding the intercalating reagent SYBR Green I DNA at the endpoint. Additionally, we demonstrate the integration of amplification and detection steps, starting from complex samples without extraction, enabling a sample-in-answer-out molecular detection protocol using DST-Pe devices. The overall simplicity of the fabrication process and its biocompatibility with all steps of molecular diagnostics demonstrate its potential for use in isolated steps or even in complete molecular diagnostics for pathogen detection.