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bioRxiv · 10.1101/2022.12.24.521858

Amplification and extraction free quantitative detection of viral nucleic acids and single-base mismatches using magnetic signal amplification circuit

Roesch, E. L.·Sack, R.·Chowdhury, M. S.·Wolgast, F.·Schilling, M.·Viereck, T.·Lak, A.
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Abstract

Established nucleic acid detection assays require extraction and purification before sequence amplification and/or enzymatic reactions, hampering their widespread applications in point-of-care (POC) formats. Magnetic immunoassays based on magnetic particle spectroscopy and magnetic nanoparticles (MNPs) are isothermal, extraction- and purification-free, and can be quantitative and benchtop, making them suitable for POC settings. Here, we demonstrate a Magnetic signal Amplification Circuit (MAC) that combines specificity of toehold-mediated DNA strand displacement with magnetic response of MNPs to a clustering/declustering process. Our MAC assays require neither amplification nor extraction of target nucleic acids, and reveal four times better sensitivity than that of a magnetic circuit without signal amplification. Using MAC, we detect a highly specific 43 nucleotides sequence of SARS-CoV-2 virus. The MAC enables sensing both DNA and RNA targets with varying lengths and resolving single-base mismatches. Our MAC can be a powerful tool for translating research of nucleic acids detection to the clinic.

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Roesch, E. L., Sack, R., Chowdhury, M. S., Wolgast, F., Schilling, M., Viereck, T., Lak, A.. 2022-12-26. Amplification and extraction free quantitative detection of viral nucleic acids and single-base mismatches using magnetic signal amplification circuit. https://doi.org/10.1101/2022.12.24.521858

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