Sample-to-Answer Microfluidic Nucleic Acid Testing (NAT) on Lab-on-a-Disc for Malaria Detection at Point of Need

One of the grand challenges for field-deployable NATs is related to the front end of the assays—nucleic acid extraction from raw samples. The ideal nucleic acid sample preparation should be simple, scalable, and easy-to-operate. In this chapter, we present a lab-on-a-disc NAT device for sample-to-answer malaria diagnosis. The parasite DNA sample preparation and subsequent real-time LAMP detection are seamlessly integrated on a disposable single microfluidic compact disc, driven by energy-efficient, non–centrifuge-based magnetic field interactions. Each disc contains four parallel testing units, which could be configured either as four identical tests or as four species-specific tests. When configured as species-specific tests, it could identify two of the most life-threatening malaria species (P. falciparum and P. vivax). The reagent disc with a 4-plex analyzer (discussed in Chapter 1 ) is capable of processing four samples simultaneously with 40 min turnaround time. It achieves a detection limit of ~0.5 parasites/μl for whole blood, sufficient for detecting asymptomatic parasite carriers. The assay is performed with an automated device described in Chapter 14. The combination of sensitivity, specificity, cost, and scalable sample preparation suggests the real-time fluorescence LAMP device could be particularly useful for malaria screening in field settings.