title: Non-instrumented nucleic acid amplification (NINA): instrument-free molecular malaria diagnostics for low-resource settings.
abstract: We have achieved the first complete, non-instrumented nucleic acid amplification test (NAAT) using a calcium oxide heat source thermally linked to an engineered phase change material. These two components alone maintain a thermal profile suitable for the loop-mediated isothermal amplification assay. Starting with computational fluid dynamics analysis, we identified nominal geometry for the exothermic reaction chamber, phase change material chamber, thermal insulation, and packaging. Using this model, we designed and fabricated an alpha prototype assay platform. We have verified the function of this multi-pathogen-capable platform with both fluorescent and visual turbidity indications using samples spiked with malaria DNA. Both the exothermically heated platform samples and samples heated on a Perkin-Elmer GeneAmp9600 thermocycler were first incubated at 62°C for 45 minutes, then heated to 95°C to terminate enzyme activity, then analyzed. Results from the exothermically heated, non-instrumented platform were comparable to those from the thermocycler. These developments will enable point-of-care diagnostics using accurate NAATs which until now have required a well-equipped laboratory. The aim of this research is to provide pathogen detection with NAAT-level sensitivity in low-resource settings where assays such as immunochromatographic strip tests are successfully used but where there is no access to the infrastructure and logistics required to operate and maintain instrument-based diagnostics.
authors.affiliation: PATH, Seattle, WA, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Labarre
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: Bernhard
authors.initials: B
authors.lastname: Weigl
mesh_terms: D016054:DNA, Protozoan / Q000235:genetics* / Q000302:isolation & purification*; D006361:Heating / Q000379:methods*; D006801:Humans; D016778:Malaria, Falciparum / Q000175:diagnosis* / Q000469:parasitology; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*
chemical_list: D016054:DNA, Protozoan