title: Solar thermal polymerase chain reaction for smartphone-assisted molecular diagnostics.
abstract: Nucleic acid-based diagnostic techniques such as polymerase chain reaction (PCR) are used extensively in medical diagnostics due to their high sensitivity, specificity and quantification capability. In settings with limited infrastructure and unreliable electricity, however, access to such devices is often limited due to the highly specialized and energy-intensive nature of the thermal cycling process required for nucleic acid amplification. Here we integrate solar heating with microfluidics to eliminate thermal cycling power requirements as well as create a simple device infrastructure for PCR. Tests are completed in less than 30 min, and power consumption is reduced to 80 mW, enabling a standard 5.5 Wh iPhone battery to provide 70 h of power to this system. Additionally, we demonstrate a complete sample-to-answer diagnostic strategy by analyzing human skin biopsies infected with Kaposi's Sarcoma herpesvirus (KSHV/HHV-8) through the combination of solar thermal PCR, HotSHOT DNA extraction and smartphone-based fluorescence detection. We believe that exploiting the ubiquity of solar thermal energy as demonstrated here could facilitate broad availability of nucleic acid-based diagnostics in resource-limited areas.
authors.affiliation: Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14853.
authors.forename: Li
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Department of Biomedical Engineering, Cornell University, Ithaca, New York 14853.
authors.forename: Matthew
authors.initials: M
authors.lastname: Mancuso
authors.affiliation: School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853.
authors.forename: Zhengda
authors.initials: Z
authors.lastname: Lu
authors.affiliation: Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065.
authors.forename: Gunkut
authors.initials: G
authors.lastname: Akar
authors.affiliation: Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065.
authors.forename: Ethel
authors.initials: E
authors.lastname: Cesarman
authors.affiliation: Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14853.
authors.forename: David
authors.initials: D
authors.lastname: Erickson
mesh_terms: D000818:Animals; D040421:Cell Phone; D004279:DNA, Viral / Q000032:analysis / Q000378:metabolism; D019288:Herpesvirus 8, Human / Q000235:genetics; D006801:Humans; D051379:Mice; D044085:Microfluidics / Q000295:instrumentation / Q000379:methods; D021141:Nucleic Acid Amplification Techniques / Q000295:instrumentation* / Q000379:methods; D020411:Oligonucleotide Array Sequence Analysis; D012867:Skin / Q000821:virology; D012993:Solar Energy
chemical_list: D004279:DNA, Viral