Performance at elevated temperatures.

<p><b>(a)</b> The temperature-time curve (<math><mrow>X<mo stretchy="true">¯</mo></mrow></math> ± s) shows smoother ramp-up and extended holdover between 57°C and 62°C (dashed lines) at a 45°C ambient temperature compared to 22°C. (n = 3) <b>(b)</b> Ramp-up time decreases by 1 minute (**p = 0.006) and holdover time increases by 60% compared to room temperature (*p = 0.04). (n = 3).</p

Device design.

<p><b>(a)</b> Labeled vertical cross-section and <b>(b)</b> photograph of used, proof-of-concept, direct liquid-vapor phase change, and isothermal chemical heater. The exothermic reaction occurs in a standard laboratory 5 mL tube and is initiated by the addition of methanol to the tube.</p

Representative temperature-time curves.

<p>The isothermal chemical heater shows relatively flat temperature-time profiles between 57°C and 62°C (dashed lines).</p

Ramp-up and holdover times.

<p><b>(a)</b> Ramp-up times (<math><mrow>X<mo stretchy="true">¯</mo></mrow></math> ± s) are reduced (*p = 0.018) and holdover times (<math><mrow>X<mo stretchy="true">¯</mo></mrow></math> ± s) show no change with the addition of sodium chloride to the magnesium-iron fuel pack. (n = 3) <b>(b)</b> In contrast, the addition of copper (II) chloride does not significantly affect ramp-up, but significantly reduces holdover (**p = 0.005). (n = 3) <b>†</b> indicates identical data points.</p

Melt curve analysis of the HIV-1 and β-actin biplex reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay.

<p>Melt analysis showed products specific to HIV-1 at 78°C and β-actin at 89°C as seen in the singleplex assays. Specificity was confirmed in the presence of normal human plasma (NHP) without HIV-1 or β-actin (negative control) and showed no amplification (n = 3).</p

A comparison of the effects on the limit of detection (LOD) of assays heated by the non-instrumented nucleic acid amplification (NINA) heater.

<p>Combination of assays run with and without warm-up ramp and with or without oil are evaluated. Table entries show the number of replicates that returned a positive result as the numerator of a fraction showing the total number of replicates run in the denominator.</p><p>A comparison of the effects on the limit of detection (LOD) of assays heated by the non-instrumented nucleic acid amplification (NINA) heater.</p

HIV LAMP amplicon detection via Milenia test strips.

<p>(A) Milenia strips used for the detection of fluorescein isothiocyanate (FITC)/biotin-labeled amplicons. Image to the right shows a positive result while image to the left is a negative result. (B) Best cassettes for the dual detection of FITC/biotin (HIV assay) and digoxigenin (DIG)/biotin (β-actin assay)–labeled amplicons. Image shows a positive result for both FITC/biotin amplicons and DIG/biotin amplicons.</p

Average temperature profiles of 74 runs with nine prototype non-instrumented nucleic acid amplification (NINA) heaters.

<p>Error bars show one standard deviation. Four devices were removed from testing when a failure mode rendered them no longer able to maintain temperature within specification. Final run data are not included in the graph. Mean time between failures (MTBF) for the failed devices is 14 runs.</p

Three non-instrumented nucleic acid amplification (NINA) heaters were conditioned in an environmental chamber, and the performance of each heater was determined at multiple temperatures (12°C, 14°C, 16°C, 30°C, 31°C, and 32°C).

<p>Averages are shown. The green lines show averages that were within the specification of 61.5°C +/−1.5°C. The red lines show runs that over-heated, and the blue lines show runs that fell below the test specifications.</p

Reverse transcription loop-mediated isothermal amplification (RT-LAMP) HIV-1 assay specifications.

<p>Reverse transcription loop-mediated isothermal amplification (RT-LAMP) HIV-1 assay specifications.</p