Portable real-time colorimetric LAMP-device for rapid quantitative detection of nucleic acids in crude samples

Sci Rep. 2022 Mar 8;12(1):3775. doi: 10.1038/s41598-022-06632-7.

Abstract

Loop-mediated isothermal amplification is known for its high sensitivity, specificity and tolerance to inhibiting-substances. In this work, we developed a device for performing real-time colorimetric LAMP combining the accuracy of lab-based quantitative analysis with the simplicity of point-of-care testing. The device innovation lies on the use of a plastic tube anchored vertically on a hot surface while the side walls are exposed to a mini camera able to take snapshots of the colour change in real time during LAMP amplification. Competitive features are the rapid analysis (< 30 min), quantification over 9 log-units, crude sample-compatibility (saliva, tissue, swabs), low detection limit (< 5 copies/reaction), smartphone-operation, fast prototyping (3D-printing) and ability to select the dye of interest (Phenol red, HNB). The device's clinical utility is demonstrated in cancer mutations-analysis during the detection of 0.01% of BRAF-V600E-to-wild-type molecules from tissue samples and COVID-19 testing with 97% (Ct < 36.8) and 98% (Ct < 30) sensitivity when using extracted RNA and nasopharyngeal-swabs, respectively. The device high technology-readiness-level makes it a suitable platform for performing any colorimetric LAMP assay; moreover, its simple and inexpensive fabrication holds promise for fast deployment and application in global diagnostics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • COVID-19 / diagnosis*
  • COVID-19 / virology
  • COVID-19 Nucleic Acid Testing / instrumentation
  • COVID-19 Nucleic Acid Testing / methods*
  • Colorimetry
  • Humans
  • Limit of Detection
  • Molecular Diagnostic Techniques
  • Nasopharynx / virology
  • Neoplasms / diagnosis
  • Neoplasms / genetics
  • Neoplasms / pathology
  • Nucleic Acid Amplification Techniques
  • Point-of-Care Testing
  • Proto-Oncogene Proteins B-raf / genetics
  • RNA, Viral / analysis
  • RNA, Viral / metabolism
  • SARS-CoV-2 / genetics
  • SARS-CoV-2 / isolation & purification
  • Sensitivity and Specificity
  • Smartphone

Substances

  • RNA, Viral
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf

Supplementary concepts

  • LAMP assay