Ultracompact sample-to-answer nucleic acid test on USB stick

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Increased malaria control efforts have resulted in a dramatic reduction in the global malaria incidence over the past decade, and the World Health Organization has endorsed the ambitious goal of achieving worldwide malaria elimination and eradication. A change in focus from malaria control to malaria elimination requires easy and efficient ways to rapidly screen for malaria. Current malaria screening tests rely almost exclusively on microscopy and immunological tests. Both methods could miss significant information due to their limited detection abilities. Nucleic acid testing (NAT) is currently the most sensitive method available. Unfortunately, NAT-based methods developed to date mostly require certain infrastructures and skilled technicians. There is a critical need for an improved malaria screening test that combines the benefits of lateral flow-based testing (scalable throughput, minimal training) and the NATs (highly sensitive and specific). The success of the proposed research would enhance the health care system domestically and globally. As a platform technology, it would allow for delivering the highly sensitive test to remote, underserved and resource-limited communities. In addition, the proposed educational and outreach activity would foster student engagement through unique hands-on-experience-based interactive activities. The research objective of this proposal is to take a multidisciplinary approach to explore a highly sensitive and scalable malaria nucleic acid screening test on a USB interfaced device. This research objective will be achieved by carrying out the following three research tasks. Task 1, assay optimization and validation, with the goal to increase the DNA extraction yield and to increase the loop-mediated isothermal amplification assay copy number sensitivity. Task 2, device integration and instrumentation, with the goal to develop the disposable microfluidic chip and the ultracompact USB interfaced analyzer. Task 3, device performance evaluation with lab-archived blood samples collected from field sites, with the goal to determine its sensitivity, specificity, reproducibility and limits of detection. The innovation of the proposed work are three folds: (1) Highly sensitive malaria isothermal amplification assay could be performed as simple as lateral flow-based testing, (2) Scalable nucleic acid testing throughput and asynchronous processing capability provided by the cascading capability of a tier tree topology of USB hubs, and (3) Versatile platform technology that can be widely disseminated to situations that demand portability, connectivity and ease-of-use.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.