Point-of-Use Detection of Environmental Fluoride via a Cell-Free Riboswitch-Based Biosensor

ACS Synth Biol. 2020 Jan 17;9(1):10-18. doi: 10.1021/acssynbio.9b00347. Epub 2019 Dec 20.


Advances in biosensor engineering have enabled the design of programmable molecular systems to detect a range of pathogens, nucleic acids, and chemicals. Here, we engineer and field-test a biosensor for fluoride, a major groundwater contaminant of global concern. The sensor consists of a cell-free system containing a DNA template that encodes a fluoride-responsive riboswitch regulating genes that produce a fluorescent or colorimetric output. Individual reactions can be lyophilized for long-term storage and detect fluoride at levels above 2 ppm, the Environmental Protection Agency's most stringent regulatory standard, in both laboratory and field conditions. Through onsite detection of fluoride in a real-world water source, this work provides a critical proof-of-principle for the future engineering of riboswitches and other biosensors to address challenges for global health and the environment.

Keywords: biosensor; cell-free systems; diagnostics; field use; riboswitches; water quality.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacillus cereus / genetics
  • Bacterial Proteins / genetics
  • Biosensing Techniques / methods*
  • Cell-Free System
  • Drinking Water / analysis*
  • Fluorides / analysis*
  • Freeze Drying
  • Genes, Reporter
  • Global Health
  • Green Fluorescent Proteins / metabolism
  • Lakes / analysis*
  • Riboswitch / genetics*
  • Swimming Pools*
  • Templates, Genetic
  • Transcription, Genetic / genetics
  • Water Pollutants, Chemical / analysis*


  • Bacterial Proteins
  • Drinking Water
  • Riboswitch
  • Water Pollutants, Chemical
  • Green Fluorescent Proteins
  • Fluorides