Very conservative estimates hold that in total 50 million people died worldwide in the 1918 flu epidemic. Most of these deaths happened in a 24-week period. Reducing the death toll from fast spreading infectious diseases will absolutely require fast diagnosis, treatment and isolation of the infected. Success requires the wide availability of simple, robust, and easy to use molecular diagnostics for use at the point-of-care for the earliest detection of the causative organism. Recent advances in materials science have made available a wide array of functional nano and microscale particles. Incorporation of these particles as composites into plastic microfluidic devices provides new opportunities to separate biomolecules from microliter and sub-microliter sample volumes. We have developed a plastic lab-on-a-chip platform for sample preparation, amplification and detection of viral RNA in human samples using microfluidic channels. These devices are capable of lysing viral particles and binding, concentrating and eluting nucleic acids from influenza infected mammalian samples of 10 l or less. The hypothesis to be tested is that plastic microfluidic diagnostic chips with nanoscale features can detect and identify influenza A in microliter-scale human nasopharyngeal samples with a specificity and sensitivity comparable or better than presently available point-of-care testing. We have demonstrated at the bench that the components of the chip work with simulated samples infected with influenza. Our long term goal is to develop a portable, relatively inexpensive molecular diagnostic system that can be used in a variety of healthcare settings to quickly diagnose and identify specific flu strains in real human samples. In addition, we aim to create devices that can be used in low resource settings that are made of polymeric materials with few or no silicon or glass components. To further this effort, we have teamed with clinicians at the Boston University Medical Center to begin work with real samples and to perform an initial study of specificity and sensitivity using a moderately sized group of patients. In order to develop this technology for real-world clinical and field use the following aims are proposed: (1) Optimize the chip design to result in faster time-to-answer with better performance. Now that we have a working prototype system in hand, we will examine each of the individual components to improve the efficiency of the device. (2) Optimize the assay (reagents and protocol) for faster time-to-answer and reliability. Engineering of the device itself needs to proceed side by side with assay development. In microfluidic devices, it is rarely as simple as shrinking down a bench top assay into the small volume setting. (3) Determine whether the microfluidic diagnostic is comparable or better in specificity and sensitivity to state of the art diagnostic assays using human nasopharyngeal samples. Samples will be collected at BUMC Emergency Department from patients presenting with influenza-like symptoms. The chip based assay will be compared to viral culture, hemagglutinin inhibition and bench-top RT-PCR assays. More effective control of the spread of infectious diseases requires a combination of prevention efforts and the widespread availability of inexpensive and accurate diagnostics. Probes to amplify and identify viral nucleic acids are available for influenza, but molecular detection of the virus is not widely performed due to complicated protocols. Dedicated engineering of test protocols (sample preparation, separations, dilutions, washing, blocking, and detection) and devices is required to move these technologies out of the research laboratory and into the field where they can have a more immediate impact on public health.
