Development of Portable Fluorescence Microplate Reader Equipped with Indium Tin Oxide Glass Heater for Loop-mediated Isothermal Amplification

We developed a portable fluorescence microplate reader equipped with an indium tin oxide (ITO) glass heater for nucleic acid testing based on loop-mediated isothermal amplification (LAMP). The components used for detection (e.g., LEDs, optical filters, the microwell plate, the ITO glass heater, and photodiodes) are arranged in parallel on a straight line. This optical placement allows us to simultaneously heat nine sample solutions and monitor the fluorescence intensity amplified by the LAMP reaction despite the analysis instrument being handheld. This simultaneous monitoring was demonstrated by the LAMP reaction using positive and negative controls. In addition, the microplate reader was applied to the variety discrimination of rice, and Koshihikari rice was successfully discriminated from four types of milled rice using the microplate reader. The developed microplate reader will be useful for on-site nucleic acid testing because it can be operated using batteries and is portable.