Standard microplate based enzyme-linked immunosorbent assays (ELISA) are widely utilized for various nanomedicine, molecular sensing, and disease screening applications, and this multiwell plate batched analysis dramatically reduces diagnosis costs per patient compared to nonbatched or nonstandard tests. However, their use in resource-limited and field-settings is inhibited by the necessity for relatively large and expensive readout instruments. To mitigate this problem, we created a hand-held and cost-effective cellphone-based colorimetric microplate reader, which uses a 3D-printed opto-mechanical attachment to hold and illuminate a 96-well plate using a light-emitting-diode (LED) array. This LED light is transmitted through each well, and is then collected via 96 individual optical fibers. Captured images of this fiber-bundle are transmitted to our servers through a custom-designed app for processing using a machine learning algorithm, yielding diagnostic results, which are delivered to the user within ∼1 min per 96-well plate, and are visualized using the same app. We successfully tested this mobile platform in a clinical microbiology laboratory using FDA-approved mumps IgG, measles IgG, and herpes simplex virus IgG (HSV-1 and HSV-2) ELISA tests using a total of 567 and 571 patient samples for training and blind testing, respectively, and achieved an accuracy of 99.6%, 98.6%, 99.4%, and 99.4% for mumps, measles, HSV-1, and HSV-2 tests, respectively. This cost-effective and hand-held platform could assist health-care professionals to perform high-throughput disease screening or tracking of vaccination campaigns at the point-of-care, even in resource-poor and field-settings. Also, its intrinsic wireless connectivity can serve epidemiological studies, generating spatiotemporal maps of disease prevalence and immunity.

Key challenges with point-of-care (POC) nucleic acid tests include achieving a low-cost, portable form factor, and stable readout, while also retaining the same robust standards of benchtop lab-based tests. We addressed two crucial aspects of this problem, identifying a chemical additive, hydroxynaphthol blue, that both stabilizes and significantly enhances intercalator-based fluorescence readout of nucleic acid concentration, and developing a cost-effective fiber-optic bundle-based fluorescence microplate reader integrated onto a mobile phone. Using loop-mediated isothermal amplification on lambda DNA we achieve a 69-fold increase in signal above background, 20-fold higher than the gold standard, yielding an overall limit of detection of 25 copies/μL within an hour using our mobile-phone-based platform. Critical for a point-of-care system, we achieve a >60% increase in fluorescence stability as a function of temperature and time, obviating the need for manual baseline correction or secondary calibration dyes. This field-portable and cost-effective mobile-phone-based nucleic acid amplification and readout platform is broadly applicable to other real-time nucleic acid amplification tests by similarly modulating intercalating dye performance and is compatible with any fluorescence-based assay that can be run in a 96-well microplate format, making it especially valuable for POC and resource-limited settings.

The cause of Lyme disease, Borrelia burgdorferi, was discovered in 1983. A 2-tiered testing protocol was established for serodiagnosis in 1994, involving an enzyme immunoassay (EIA) or indirect fluorescence antibody, followed (if reactive) by immunoglobulin M and immunoglobulin G Western immunoblots. These assays were prepared from whole-cell cultured B. burgdorferi, lacking key in vivo expressed antigens and expressing antigens that can bind non-Borrelia antibodies. Additional drawbacks, particular to the Western immunoblot component, include low sensitivity in early infection, technical complexity, and subjective interpretation when scored by visual examination. Nevertheless, 2-tiered testing with immunoblotting remains the benchmark for evaluation of new methods or approaches. Next-generation serologic assays, prepared with recombinant proteins or synthetic peptides, and alternative testing protocols, can now overcome or circumvent many of these past drawbacks. This article describes next-generation serodiagnostic testing for Lyme disease, focusing on methods that are currently available or near-at-hand.