A low-cost fluorescence reader for in vitro transcription and nucleic acid detection with Cas13a

Autoři: Florian Katzmeier aff001;  Lukas Aufinger aff001;  Aurore Dupin aff001;  Jorge Quintero aff002;  Matthias Lenz aff001;  Ludwig Bauer aff001;  Sven Klumpe aff001;  Dawafuti Sherpa aff002;  Benedikt Dürr aff002;  Maximilian Honemann aff001;  Igor Styazhkin aff001;  Friedrich C. Simmel aff001;  Michael Heymann aff003
Působiště autorů: Physics Department and ZNN, Technical University of Munich, Garching, Germany aff001;  Department of Biology, Ludwig-Maximilians-Universität Munich, Martinsried, Germany aff002;  Intelligent Biointegrative Systems Group, Institute for Biomaterials and Biomolecular Systems, University Stuttgart, Germany aff003
Vyšlo v časopise: PLoS ONE 14(12)
Kategorie: Research Article
doi: https://doi.org/10.1371/journal.pone.0220091


Point-of-care testing (POCT) in low-resource settings requires tools that can operate independently of typical laboratory infrastructure. Due to its favorable signal-to-background ratio, a wide variety of biomedical tests utilize fluorescence as a readout. However, fluorescence techniques often require expensive or complex instrumentation and can be difficult to adapt for POCT. To address this issue, we developed a pocket-sized fluorescence detector costing less than $15 that is easy to manufacture and can operate in low-resource settings. It is built from standard electronic components, including an LED and a light dependent resistor, filter foils and 3D printed parts, and reliably reaches a lower limit of detection (LOD) of ≈ 6.8 nM fluorescein, which is sufficient to follow typical biochemical reactions used in POCT applications. All assays are conducted on filter paper, which allows for a flat detector architecture to improve signal collection. We validate the device by quantifying in vitro RNA transcription and also demonstrate sequence-specific detection of target RNAs with an LOD of 3.7 nM using a Cas13a-based fluorescence assay. Cas13a is an RNA-guided, RNA-targeting CRISPR effector with promiscuous RNase activity upon recognition of its RNA target. Cas13a sensing is highly specific and adaptable and in combination with our detector represents a promising approach for nucleic acid POCT. Furthermore, our open-source device may be used in educational settings, through providing low cost instrumentation for quantitative assays or as a platform to integrate hardware, software and biochemistry concepts in the future.

Klíčová slova:

Artificial light – Colorimetric assays – Filter paper – Fluorescence – Nucleic acids – Ribonucleases – Signal filtering – Signal processing


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2019 Číslo 12
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