Colorimetric Hybridization Sensor for DNA Mimic of a SARS-CoV-2 RNA Marker: Direct and Inverse Bioanalysis

This article presents a colorimetric visual biosensor designed for direct application in undiluted biofluids, which holds significant promise for point-of-need applications. Unlike traditional biosensors that struggle with heavily diluted sample matrices, the presented biosensor does not require any instrumentation or trained personnel, making it highly practical. The sensor features an oligonucleotide probe covalently attached to magnetically separable magnetite (Fe