title: A simple, inexpensive device for nucleic acid amplification without electricity-toward instrument-free molecular diagnostics in low-resource settings.
abstract: BACKGROUND
  Molecular assays targeted to nucleic acid (NA) markers are becoming increasingly important to medical diagnostics. However, these are typically confined to wealthy, developed countries; or, to the national reference laboratories of developing-world countries. There are many infectious diseases that are endemic in low-resource settings (LRS) where the lack of simple, instrument-free, NA diagnostic tests is a critical barrier to timely treatment. One of the primary barriers to the practicality and availability of NA assays in LRS has been the complexity and power requirements of polymerase chain reaction (PCR) instrumentation (another is sample preparation).
  
  
  RESULTS
  In this article, we investigate the hypothesis that an electricity-free heater based on exothermic chemical reactions and engineered phase change materials can successfully incubate isothermal NA amplification assays. We assess the heater's equivalence to commercially available PCR instruments through the characterization of the temperature profiles produced, and a minimal method comparison. Versions of the prototype for several different isothermal techniques are presented.
  
  
  CONCLUSIONS
  We demonstrate that an electricity-free heater based on exothermic chemical reactions and engineered phase change materials can successfully incubate isothermal NA amplification assays, and that the results of those assays are not significantly different from ones incubated in parallel in commercially available PCR instruments. These results clearly suggest the potential of the non-instrumented nucleic acid amplification (NINA) heater for molecular diagnostics in LRS. When combined with other innovations in development that eliminate power requirements for sample preparation, cold reagent storage, and readout, the NINA heater will comprise part of a kit that should enable electricity-free NA testing for many important analytes.
authors.affiliation: PATH, Seattle, Washington, United States of America. plabarr@path.org
authors.forename: Paul
authors.initials: P
authors.lastname: LaBarre
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Hawkins
authors.forename: Jay
authors.initials: J
authors.lastname: Gerlach
authors.forename: Jared
authors.initials: J
authors.lastname: Wilmoth
authors.forename: Andrew
authors.initials: A
authors.lastname: Beddoe
authors.forename: Jered
authors.initials: J
authors.lastname: Singleton
authors.forename: David
authors.initials: D
authors.lastname: Boyle
authors.forename: Bernhard
authors.initials: B
authors.lastname: Weigl
mesh_terms: D003906:Developing Countries; D004560:Electricity; D006358:Hot Temperature; D025202:Molecular Diagnostic Techniques / Q000191:economics* / Q000295:instrumentation* / Q000592:standards; D021141:Nucleic Acid Amplification Techniques / Q000191:economics* / Q000295:instrumentation* / Q000592:standards; D010963:Plasmodium falciparum / Q000235:genetics; D012015:Reference Standards