title: Electricity-free amplification and detection for molecular point-of-care diagnosis of HIV-1.
abstract: In resource-limited settings, the lack of decentralized molecular diagnostic testing and sparse access to centralized medical facilities can present a critical barrier to timely diagnosis, treatment, and subsequent control and elimination of infectious diseases. Isothermal nucleic acid amplification methods, including reverse transcription loop-mediated isothermal amplification (RT-LAMP), are well-suited for decentralized point-of-care molecular testing in minimal infrastructure laboratories since they significantly reduce the complexity of equipment and power requirements. Despite reduced complexity, however, there is still a need for a constant heat source to enable isothermal nucleic acid amplification. This requirement poses significant challenges for laboratories in developing countries where electricity is often unreliable or unavailable. To address this need, we previously developed a low-cost, electricity-free heater using an exothermic reaction thermally coupled with a phase change material. This heater achieved acceptable performance, but exhibited considerable variability. Furthermore, as an enabling technology, the heater was an incomplete diagnostic solution. Here we describe a more precise, affordable, and robust heater design with thermal standard deviation <0.5°C at operating temperature, a cost of approximately US$.06 per test for heater reaction materials, and an ambient temperature operating range from 16°C to 30°C. We also pair the heater with nucleic acid lateral flow (NALF)-detection for a visual readout. To further illustrate the utility of the electricity-free heater and NALF-detection platform, we demonstrate sensitive and repeatable detection of HIV-1 with a ß-actin positive internal amplification control from processed sample to result in less than 80 minutes. Together, these elements are building blocks for an electricity-free platform capable of isothermal amplification and detection of a variety of pathogens.
authors.affiliation: PATH, Seattle, Washington, United States of America.
authors.forename: Jered
authors.initials: J
authors.lastname: Singleton
authors.affiliation: PATH, Seattle, Washington, United States of America.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Osborn
authors.affiliation: PATH, Seattle, Washington, United States of America.
authors.forename: Lorraine
authors.initials: L
authors.lastname: Lillis
authors.affiliation: PATH, Seattle, Washington, United States of America.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Hawkins
authors.affiliation: PATH, Seattle, Washington, United States of America.
authors.forename: Dylan
authors.initials: D
authors.lastname: Guelig
authors.affiliation: Oregon Health and Science University School of Medicine, Portland, Oregon, United States of America.
authors.forename: Will
authors.initials: W
authors.lastname: Price
authors.affiliation: PATH, Seattle, Washington, United States of America.
authors.forename: Rachel
authors.initials: R
authors.lastname: Johns
authors.affiliation: PATH, Seattle, Washington, United States of America.
authors.forename: Kelly
authors.initials: K
authors.lastname: Ebels
authors.affiliation: PATH, Seattle, Washington, United States of America.
authors.forename: David
authors.initials: D
authors.lastname: Boyle
authors.affiliation: PATH, Seattle, Washington, United States of America.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Weigl
authors.affiliation: PATH, Seattle, Washington, United States of America.
authors.forename: Paul
authors.initials: P
authors.lastname: LaBarre
mesh_terms: D004560:Electricity; D004867:Equipment Design; D015658:HIV Infections / Q000097:blood / Q000175:diagnosis* / Q000821:virology; D015497:HIV-1 / Q000235:genetics* / Q000302:isolation & purification; D006358:Hot Temperature; D006801:Humans; D021141:Nucleic Acid Amplification Techniques / Q000295:instrumentation*; D019095:Point-of-Care Systems; D012367:RNA, Viral / Q000097:blood / Q000235:genetics / Q000302:isolation & purification
chemical_list: D012367:RNA, Viral