Abstract: Provided herein are methods and devices for rapidly and accurately heating fluid droplets surrounded by a gas-phase medium, such as air. Sub-nanoliter fluid droplets can be rapidly heated by nanoscale field effect transistors via microwave heating by an applied AC voltage to the FET. The heating is in a well-defined interior portion of the fluid droplet, with minimal heating of the outer portion of the fluid droplet, thereby minimizing evaporation. In this manner, rapid thermal cycling is possible, including independently and in parallel for a plurality of droplets. Accordingly, the methods and devices provided herein are used in point-of-care detection such as by PCR that is high speed, robust and of low cost.

Abstract: Provided are methods and devices for label-free detection of nucleic acids that are amplified by polymerase chain reaction. A solution containing the components necessary for a PCR is introduced to a microfluidic amplification chamber and an electric field applied to a confined region in which PCR occurs. PCR product generated in the confined region is detected by measuring an electrical parameter that is, for example, solution impedance. The devices and methods provided herein are used, for example, in assays to detect one or more pathogens or for point-of-care tests. In an aspect, the PCR product is confined to droplets and the assay relates to detecting an electrical parameter of a flowing droplet, thereby detecting PCR product without a label. In an aspect, the PCR occurs in the droplet.

Abstract: Provided herein are methods and devices for rapidly and accurately heating fluid droplets surrounded by a gas-phase medium, such as air. Sub-nanoliter fluid droplets can be rapidly heated by nanoscale field effect transistors via microwave heating by an applied AC voltage to the FET. The heating is in a well-defined interior portion of the fluid droplet, with minimal heating of the outer portion of the fluid droplet, thereby minimizing evaporation. In this manner, rapid thermal cycling is possible, including independently and in parallel for a plurality of droplets. Accordingly, the methods and devices provided herein are used in point-of-care detection such as by PCR that is high speed, robust and of low cost.

Abstract: Provided are methods and devices for label-free detection of nucleic acids that are amplified by polymerase chain reaction. A solution containing the components necessary for a PCR is introduced to a microfluidic amplification chamber and an electric field applied to a confined region in which PCR occurs. PCR product generated in the confined region is detected by measuring an electrical parameter that is, for example, solution impedance. The devices and methods provided herein are used, for example, in assays to detect one or more pathogens or for point-of-care tests. In an aspect, the PCR product is confined to droplets and the assay relates to detecting an electrical parameter of a flowing droplet, thereby detecting PCR product without a label. In an aspect, the PCR occurs in the droplet.