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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.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.

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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Temperature of mock reactions incubated at different body locations.Each plot shows the temperature traces of mock RPA reactions incubated by 5 volunteers at 1 of 4 body location tested. Mock reactions were (A) held in the axilla, (B) taped to the abdomen, (C) placed in a rear trouser pocket, and (D) held in a closed fist.
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pone-0112146-g002: Temperature of mock reactions incubated at different body locations.Each plot shows the temperature traces of mock RPA reactions incubated by 5 volunteers at 1 of 4 body location tested. Mock reactions were (A) held in the axilla, (B) taped to the abdomen, (C) placed in a rear trouser pocket, and (D) held in a closed fist.

Mentions: The temperature of mock RPA reactions was measured at various body locations to estimate the temperature that an RPA reaction would reach if incubated using body heat. Figure 2 shows the temperature traces of mock RPA reactions incubated by 5 volunteers at 4 body locations. Mock reactions held in the axilla outside of clothing (Fig. 2A), taped to the abdomen under clothing (Fig. 2B), placed in a rear trouser pocket (Fig. 2C), and held in a closed fist (Fig. 2D) had average temperatures of 34.8±0.6, 31.3±1.7, 33.1±0.5, and 33.4±2.7 degrees Celsius, respectively. In less than three minutes, all mock reactions reached a temperature of 31 degrees Celsius, the temperature required for all RPA reactions to amplify DNA to detectable levels [15]. Because the temperature of mock reactions was closest to the temperature recommended for RPA (37 degrees Celsius) when incubated in the axilla, this site was chosen as the site of incubation 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 incubated at different body locations.Each plot shows the temperature traces of mock RPA reactions incubated by 5 volunteers at 1 of 4 body location tested. Mock reactions were (A) held in the axilla, (B) taped to the abdomen, (C) placed in a rear trouser pocket, and (D) held in a closed fist.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0112146-g002: Temperature of mock reactions incubated at different body locations.Each plot shows the temperature traces of mock RPA reactions incubated by 5 volunteers at 1 of 4 body location tested. Mock reactions were (A) held in the axilla, (B) taped to the abdomen, (C) placed in a rear trouser pocket, and (D) held in a closed fist.
Mentions: The temperature of mock RPA reactions was measured at various body locations to estimate the temperature that an RPA reaction would reach if incubated using body heat. Figure 2 shows the temperature traces of mock RPA reactions incubated by 5 volunteers at 4 body locations. Mock reactions held in the axilla outside of clothing (Fig. 2A), taped to the abdomen under clothing (Fig. 2B), placed in a rear trouser pocket (Fig. 2C), and held in a closed fist (Fig. 2D) had average temperatures of 34.8±0.6, 31.3±1.7, 33.1±0.5, and 33.4±2.7 degrees Celsius, respectively. In less than three minutes, all mock reactions reached a temperature of 31 degrees Celsius, the temperature required for all RPA reactions to amplify DNA to detectable levels [15]. Because the temperature of mock reactions was closest to the temperature recommended for RPA (37 degrees Celsius) when incubated in the axilla, this site was chosen as the site of incubation 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.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.

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