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We have developed a multichannel air displacement pipet with reconfigurable channels for nonstandard liquid handling applications. While linear multichannel pipets enable many established assays, they do not support analytical tools with customized liquid holding geometries, specifically paper-based microfluidic devices. Using our pipet, complex paper-based microfluidic devices can be fabricated without requiring multiple, time-consuming motions with a single-channel pipet or device designs limited to the configurations of traditional multichannel pipets. We created this tool by modifying a commercial 8-channel pipet using machined and 3D-printed components. We demonstrate the quantitative capabilities of our tool by comparing its performance to that of a calibrated, single-channel pipet in volume delivery experiments. Our reconfigurable pipet supports the advancement of custom analytical tools with nonstandard liquid handling requirements and provides an ergonomic alternative to commercial equipment for developers of paper-based devices. [ABSTRACT FROM AUTHOR]

During epidemics, such as the frequent and devastating Ebola virus outbreaks that have historically plagued regions of Africa, serological surveillance efforts are critical for viral containment and the development of effective antiviral therapeutics. Antibody serology can also be used retrospectively for population-level surveillance to provide a more complete estimate of total infections. Ebola surveillance efforts rely on enzyme-linked immunosorbent assays (ELISAs), which restrict testing to laboratories and are not adaptable for use in resource-limited settings. In this manuscript, we describe a paper-based immunoassay capable of detecting anti-Ebola IgG using Ebola virus envelope glycoprotein ectodomain (GP) as the affinity reagent. We evaluated seven monoclonal antibodies (mAbs) against GP—KZ52, 13C6, 4G7, 2G4, c6D8, 13F6, and 4F3—to elucidate the impact of binding affinity and binding epitope on assay performance and, ultimately, result interpretation. We used biolayer interferometry to characterize the binding of each antibody to GP before assessing their performance in our paper-based device. Binding affinity (KD) and on rate (kon) were major factors influencing the sensitivity of the paper-based immunoassay. mAbs with the best KD (3–25 nM) exhibited the lowest limits of detection (ca. μg mL−1), while mAbs with KD > 25 nM were undetectable in our device. Additionally, and most surprisingly, we determined that observed signals in paper devices were directly proportional to kon. These results highlight the importance of ensuring that the quality of recognition reagents is sufficient to support desired assay performance and suggest that the strength of an individual's immune response can impact the interpretation of assay results. [ABSTRACT FROM AUTHOR]

The development of viable point-of-care diagnostic formats is integral to achieving better patient care and improved outcomes. The need for robust and low-cost tests is especially important in under-resourced and rural settings. Perhaps the greatest challenge is ensuring that an untrained individual is capable of operating and interpreting the test, out with a care facility. Here we present a paper-based diagnostic device capable of sensing miR-29a using both colorimetric and surface enhanced Raman scattering (SERS) analysis. Rather, than carry out the two types of analyses in tandem, we envisage that the colorimetric output is easy enough to be interpreted by the untrained-individual administering the test to provide them with qualitative feedback. If deemed positive, the test can be further validated at a centralized care facility using a handheld-Raman spectrometer to provide a semi-quantitative result. Detection of miR-29a, a microRNA associated with myocardial infarction, was achieved at a level of pg μL−1 through the combination of three-dimensional paper-based microfluidics, colorimetric detection, and surface enhanced Raman scattering (SERS) analysis. RGB analysis of the colorimetric output generated from samples containing miR-29a at different concentrations (18–360 pg μL−1) showed differentiation from the control sample, however significant repeat variability indicated that it could not be used for quantifying miR-29a levels. However, the SERS analysis exhibited greater reproducibility at varying concentrations, achieving an LoD of 47 pg μL−1. The union of the paper-based device and the two analysis methods resulted in the production of a sensitive, reproducible and facile, point of care test (POCT), which paves the way for future implementation in the diagnosis of a range of diseases. [ABSTRACT FROM AUTHOR]

While a number of assays for soluble analytes have been developed using paper-based microfluidic devices, the detection and analysis of blood cells has remained an outstanding challenge. In this Feature, we discuss how the properties of paper determine the performance of paper-based microfluidic devices and permit the design of cellular assays, which can ultimately impact disparities in healthcare that exist in limited-resource settings. [ABSTRACT FROM AUTHOR]

Information about the 1st International Point-of-Care Diagnostic Workshop held in Nairobi, Kenya in 2015 is presented. Topics include emerging diagnostic technologies which include webcam microscope, aqueous multiphase systems and egg beater centrifuge, plasma separation on chip, and shrink-wrap microfluidics. The event featured presenters and particpants from different countries including Uganda, Zimbabwe, and South Africa.