02773nas a2200265 4500008004100000022001400041245009700055210006900152260000900221300001200230490000600242520198800248100002102236700002402257700002102281700002102302700001802323700001602341700001802357700001702375700001702392700002002409700001802429856006002447 2014 eng d a1932-620300aElectricity-free amplification and detection for molecular point-of-care diagnosis of HIV-1.0 aElectricityfree amplification and detection for molecular pointo c2014 ae1136930 v93 a
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.
1 aSingleton, Jered1 aOsborn, Jennifer, L1 aLillis, Lorraine1 aHawkins, Kenneth1 aGuelig, Dylan1 aPrice, Will1 aJohns, Rachel1 aEbels, Kelly1 aBoyle, David1 aWeigl, Bernhard1 aLaBarre, Paul uhttps://www.microfluidicsciences.com/drupal/?q=node/20001786nas a2200169 4500008004100000022001400041245008200055210006900137260001600206490000900222520124900231100001801480700001701498700002101515700002001536856006001556 2011 ENG d a0277-786X00aInstrument-free nucleic acid amplification assays for global health settings.0 aInstrumentfree nucleic acid amplification assays for global heal c2011 May 160 v80293 aMany infectious diseases that affect global health are most accurately diagnosed through nucleic acid amplification and detection. However, existing nucleic acid amplification tests are too expensive and complex for most low-resource settings. The small numbers of centralized laboratories that exist in developing countries tend to be in urban areas and primarily cater to the affluent. In contrast, rural area health care facilities commonly have only basic equipment and health workers have limited training and little ability to maintain equipment and handle reagents.(1) Reliable electric power is a common infrastructure shortfall. In this paper, we discuss a practical approach to the design and development of non-instrumented molecular diagnostic tests that exploit the benefits of isothermal amplification strategies. We identify modular instrument-free technologies for sample collection, sample preparation, amplification, heating, and detection. By appropriately selecting and integrating these instrument-free modules, we envision development of an easy to use, infrastructure independent diagnostic test that will enable increased use of highly accurate molecular diagnostics at the point of care in low-resource settings.
1 aLaBarre, Paul1 aBoyle, David1 aHawkins, Kenneth1 aWeigl, Bernhard uhttps://www.microfluidicsciences.com/drupal/?q=node/21003020nas a2200313 4500008004100000022001400041245015500055210006900210260000900279300001100288490000600299520199700305653002502302653001602327653002002343653003602363653004202399653002602441653002402467100001802491700002402509700001702533700001902550700001902569700002102588700001702609700002002626856006002646 2011 eng d a1932-620300aA simple, inexpensive device for nucleic acid amplification without electricity-toward instrument-free molecular diagnostics in low-resource settings.0 asimple inexpensive device for nucleic acid amplification without c2011 ae197380 v63 aBACKGROUND: 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).
METHODOLOGY/PRINCIPAL FINDINGS: 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/SIGNIFICANCE: 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.
10aDeveloping Countries10aElectricity10aHot Temperature10aMolecular Diagnostic Techniques10aNucleic Acid Amplification Techniques10aPlasmodium falciparum10aReference Standards1 aLaBarre, Paul1 aHawkins, Kenneth, R1 aGerlach, Jay1 aWilmoth, Jared1 aBeddoe, Andrew1 aSingleton, Jered1 aBoyle, David1 aWeigl, Bernhard uhttps://www.microfluidicsciences.com/drupal/?q=node/209