ポータブル、低コスト、ポイントオブケア向けDNA増幅キット、インピーダンスベース検出による分散型薬剤耐性診断

This study introduces a low-cost, portable DNA amplification kit that performs a modified loop-mediated isothermal amplification (LAMP) reaction, which produces DNA nanoballs and combines it with a previously developed microfluidic impedance-based digital assay to deliver a potential all-in-one, point-of-care (POC) diagnostic platform for the detection of target nucleic acids. The device combines sample processing and detection in a single streamlined workflow, utilizing induction heating and Arduino-based temperature control, along with several engineering innovations, including a custom-designed polycarbonate microtube holder and an optimized thermocouple-based temperature-control feedback system, ensuring stable reaction conditions for reproducible amplification. System performance was validated through the detection of a synthesized β-lactamase target DNA gene block, including samples with additional non-target background DNA. In addition to a qualitative colorimetric readout, label-free impedance-based quantification confirmed the robust production of DNA nanoballs with high specificity and minimal background interference. The amplification quality was revealed to be comparable to that of a commercial thermal cycler. Subsequent sensitivity testing using serial dilutions of the target DNA (between 10¹-10⁵ copies per μl) in a complex background DNA mixture demonstrated detection results that strongly correlated with quantitative PCR (qPCR). These findings demonstrate that the amplification kit achieves performance parity with gold-standard nucleic acid detection methods while offering portability, affordability, and ease of use. By enabling accurate, rapid, and decentralized diagnostics without reliance on laboratory infrastructure, this combined workflow holds promise for advancing infectious disease monitoring and antimicrobial resistance surveillance, among other applications, at the point of care.