A portable device for nucleic acid quantification powered by sunlight, a flame or electricity

Abstract

A decentralized approach to diagnostics can decrease the time to treatment of infectious diseases in resource-limited settings. Yet most modern diagnostic tools require stable electricity and are not portable. Here, we describe a portable device for isothermal nucleic-acid quantification that can operate with power from electricity, sunlight or a flame, and that can store heat from intermittent energy sources, for operation when electrical power is not available or reliable. We deployed the device in two Ugandan health clinics, where it successfully operated through multiple power outages, with equivalent performance when powered via sunlight or electricity. A direct comparison between the portable device and commercial qPCR (quantitative polymerase chain reaction) machines for samples from 71 Ugandan patients (29 of which were tested in Uganda) for the presence of Kaposi’s sarcoma-associated herpesvirus DNA showed 94% agreement, with the four discordant samples having the lowest concentration of the herpesvirus DNA. The device’s flexibility in power supply provides a needed solution for on-field diagnostics.

An ultraportable and versatile point-of-care DNA testing platform

“…Because of our combinatory and integrated approach, the POCKET system was extremely light and small, rendering the POCKET system, to the best of our knowledge, to be one of the smallest and most portable POC DNA testing devices. Compared with other 3D-printed or microfluidic chips, our POCKET system was more versatile for a broader range of possible sample sources and achieved multiplex detections with reduced reagent costs (table S6) (6,9,11,14,17,(27)(28)(29)(30)(31).…”

“…The needs for instrument in the sample preparation stage and/or AC power supplies have severely limited the portability of the entire POCT. Although various methods without using an AC power such as using exothermic chemical reactions or positive temperature coefficient heaters had been developed to achieve isothermal amplification (9)(10)(11)(12), those methods still weighted from hundreds to thousands of grams, too heavy to be ultraportable.…”

A versatile oscillating‐flow microfluidic PCR system utilizing a thermal gradient for nucleic acid analysis

“…Nucleic acid testing (NAT) enables the rapid and accurate detection of viruses and bacteria from a patient's sample. Current NAT instruments are bulky, expensive, and slow, limiting the potential for point‐of‐care (POC) applications (Snodgrass et al, 2018; Urdea et al, 2006; Yager, Domingo, & Gerdes, 2008). Lab‐on‐a‐chip technology has led to the development of miniaturized NAT devices for POC applications.…”

Oscillating-flow Thermal Gradient PCR

“…Nucleic acid testing (NAT) enables the rapid and accurate detection of viruses and bacteria from a patient's sample. Current NAT instruments are bulky, expensive, and slow, limiting the potential for point-of-care (POC) applications [2][3][4] . Lab-on-a-chip technology has led to the development of miniaturized NAT devices for POC applications.…”