Universal portable colorimetric isothermal nucleic acid amplification equipment for immediate diagnosis

Rapid diagnostic equipment based on nucleic acid (NA) amplification provides an effective means for disease detection, control, and prevention of virus spread. However, most contemporary diagnostic methods depend on advanced and expensive temperature control instrument and analytical equipment, which are insufficient for point-of-care testing in low-resource environments. Here we present a universal isothermal NA amplification testing equipment (UINE) for immediate diagnosis. The equipment can be heated using exothermic chemical reaction, electricity or flame, providing a unique capability to operate instantly in the field. With the assistance of phase change material (PCM), it can adjust the temperature without relying on any temperature control device. The equipment is capable of operating in ambient temperatures from −9°C to 36°C and can maintain the optimal reaction temperatures for loop-mediated isothermal amplification (LAMP), which are 63–65°C, for approximately 33–150 min. To eliminate the need for expensive inspection machines and minimize inspection costs, we employ a colorimetric visual detection method that allows direct observation of results with the naked eye. Additionally, an objective analysis method based on image processing is designed to assist in more accurately judging the detection results. We conducted LAMP tests on λ DNA and HBV DNA, achieving a limit of detection (LOD) of 46 copies/μL for HBV DNA. This demonstrate that UINE offers low detection cost, rapid detection speed, high integration and portability. UINE can be applied across various environmental conditions, particularly playing an important role in the field or low-resource environments.