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Equipment-free incubation of recombinase polymerase amplification reactions using body heat.

Crannell ZA, Rohrman B, Richards-Kortum R - PLoS ONE (2014)

Bottom Line: After measuring the temperature of mock reactions at 4 body locations, the axilla was chosen as the ideal site for comfortable, convenient incubation.Using commonly available materials, 3 methods for securing RPA reactions to the body were characterized.In a cold room with an ambient temperature of 10 degrees Celsius, all reactions containing 10 copies or 100 copies of HIV-1 DNA tested positive when incubated with body heat.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, Rice University, Houston, Texas, United States of America.

ABSTRACT
The development of isothermal amplification platforms for nucleic acid detection has the potential to increase access to molecular diagnostics in low resource settings; however, simple, low-cost methods for heating samples are required to perform reactions. In this study, we demonstrated that human body heat may be harnessed to incubate recombinase polymerase amplification (RPA) reactions for isothermal amplification of HIV-1 DNA. After measuring the temperature of mock reactions at 4 body locations, the axilla was chosen as the ideal site for comfortable, convenient incubation. Using commonly available materials, 3 methods for securing RPA reactions to the body were characterized. Finally, RPA reactions were incubated using body heat while control RPA reactions were incubated in a heat block. At room temperature, all reactions with 10 copies of HIV-1 DNA and 90% of reactions with 100 copies of HIV-1 DNA tested positive when incubated with body heat. In a cold room with an ambient temperature of 10 degrees Celsius, all reactions containing 10 copies or 100 copies of HIV-1 DNA tested positive when incubated with body heat. These results suggest that human body heat may provide an extremely low-cost solution for incubating RPA reactions in low resource settings.

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Related in: MedlinePlus

Temperature of mock reactions secured to the body with different materials.Each plot shows the temperature traces of mock RPA reactions incubated by 5 volunteers using 1 of 3 different materials. Materials tested included (A) a strip of cotton fabric, (B) a bandage, and (C) a sweatband.
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pone-0112146-g003: Temperature of mock reactions secured to the body with different materials.Each plot shows the temperature traces of mock RPA reactions incubated by 5 volunteers using 1 of 3 different materials. Materials tested included (A) a strip of cotton fabric, (B) a bandage, and (C) a sweatband.

Mentions: Several methods were tested for securing tubes to the body to allow convenient incubation of RPA reactions in the axilla. Figure 3 shows the temperature traces of mock RPA reactions incubated by 5 volunteers using 3 different methods. Mock reactions secured with a strip of cotton chitenje fabric (Fig. 3A), a bandage (Fig. 3B), and an elastic sweatband (Fig. 3C) reached an average temperature of 33.2±1.6, 32.9±1.2, and 33.5±0.7 degrees Celsius, respectively. The average time to reach 31 degrees Celsius using the chitenje fabric, a bandage, and an elastic sweatband was 2.0±2.7, 2.5±1.8, and 2.1±1.0 minutes, respectively. Because all methods produced similar temperatures, and cotton fabric is inexpensive and widely available in developing countries, tubes were secured with a strip of cotton fabric for all following experiments.


Equipment-free incubation of recombinase polymerase amplification reactions using body heat.

Crannell ZA, Rohrman B, Richards-Kortum R - PLoS ONE (2014)

Temperature of mock reactions secured to the body with different materials.Each plot shows the temperature traces of mock RPA reactions incubated by 5 volunteers using 1 of 3 different materials. Materials tested included (A) a strip of cotton fabric, (B) a bandage, and (C) a sweatband.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4221156&req=5

pone-0112146-g003: Temperature of mock reactions secured to the body with different materials.Each plot shows the temperature traces of mock RPA reactions incubated by 5 volunteers using 1 of 3 different materials. Materials tested included (A) a strip of cotton fabric, (B) a bandage, and (C) a sweatband.
Mentions: Several methods were tested for securing tubes to the body to allow convenient incubation of RPA reactions in the axilla. Figure 3 shows the temperature traces of mock RPA reactions incubated by 5 volunteers using 3 different methods. Mock reactions secured with a strip of cotton chitenje fabric (Fig. 3A), a bandage (Fig. 3B), and an elastic sweatband (Fig. 3C) reached an average temperature of 33.2±1.6, 32.9±1.2, and 33.5±0.7 degrees Celsius, respectively. The average time to reach 31 degrees Celsius using the chitenje fabric, a bandage, and an elastic sweatband was 2.0±2.7, 2.5±1.8, and 2.1±1.0 minutes, respectively. Because all methods produced similar temperatures, and cotton fabric is inexpensive and widely available in developing countries, tubes were secured with a strip of cotton fabric for all following experiments.

Bottom Line: After measuring the temperature of mock reactions at 4 body locations, the axilla was chosen as the ideal site for comfortable, convenient incubation.Using commonly available materials, 3 methods for securing RPA reactions to the body were characterized.In a cold room with an ambient temperature of 10 degrees Celsius, all reactions containing 10 copies or 100 copies of HIV-1 DNA tested positive when incubated with body heat.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, Rice University, Houston, Texas, United States of America.

ABSTRACT
The development of isothermal amplification platforms for nucleic acid detection has the potential to increase access to molecular diagnostics in low resource settings; however, simple, low-cost methods for heating samples are required to perform reactions. In this study, we demonstrated that human body heat may be harnessed to incubate recombinase polymerase amplification (RPA) reactions for isothermal amplification of HIV-1 DNA. After measuring the temperature of mock reactions at 4 body locations, the axilla was chosen as the ideal site for comfortable, convenient incubation. Using commonly available materials, 3 methods for securing RPA reactions to the body were characterized. Finally, RPA reactions were incubated using body heat while control RPA reactions were incubated in a heat block. At room temperature, all reactions with 10 copies of HIV-1 DNA and 90% of reactions with 100 copies of HIV-1 DNA tested positive when incubated with body heat. In a cold room with an ambient temperature of 10 degrees Celsius, all reactions containing 10 copies or 100 copies of HIV-1 DNA tested positive when incubated with body heat. These results suggest that human body heat may provide an extremely low-cost solution for incubating RPA reactions in low resource settings.

Show MeSH
Related in: MedlinePlus