Browsing by Author "Jiang, Xue"

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    Lateral flow immunochromatographic assay on a single piece of paper
    (Royal Society of Chemistry, 2021) Jiang, Xue; Lillehoj, Peter B.
    Lateral flow immunochromatographic assays (LFIAs) are analytical devices used to detect the presence of one or more target analytes in a liquid sample. While LFIAs are one of the simplest and inexpensive types of immunoassays, they consist of multiple components (sample pad, conjugate pad, membrane, absorbent pad, backing card) and materials, requiring time-consuming device assembly. Here, we report a unique lateral flow immunochromatographic assay constructed from a single piece of cellulose paper, which is fabricated via laser cutting. Compared with conventional lateral flow immunochromatographic devices, this single-layer immunoassay enables simpler and faster fabrication, while minimizing material consumption and overall device costs. For proof-of-concept, this device was used to detect Plasmodium falciparum histidine-rich protein 2 (PfHRP2), a biomarker for malaria infection, which could be detected at concentrations as low as 4 ng mL−1 by the naked eye with no cross reactivity with other common Plasmodium protein biomarkers. While offering similar speed and ease-of-use as conventional LFIAs with a higher detection sensitivity than existing LFIAs for PfHRP2 detection, this single-layer lateral flow immunoassay has the potential to improve malaria testing, as well as the detection of other important protein biomarkers for point-of-care testing.
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    Microneedle-based sampling of dermal interstitial fluid using a vacuum-assisted skin patch
    (Elsevier, 2024) Jiang, Xue; Wilkirson, Elizabeth C.; Bailey, Aaron O.; Russell, William K.; Lillehoj, Peter B.
    Interstitial fluid (ISF) contains a wealth of biomolecules, yet it is underutilized for diagnostic testing due to a lack of rapid and simple techniques for collecting abundant amounts of fluid. Here, we report a simple and minimally invasive technique for rapidly sampling larger quantities of ISF from human skin. A microneedle array is used to generate micropores in skin from which ISF is extracted using a vacuum-assisted skin patch. Using this technique, an average of 20.8 μL of dermal ISF is collected in 25 min, which is an ∼6-fold improvement over existing sampling methods. Proteomic analysis of collected ISF reveals that it has nearly identical protein composition as blood, and >600 medically relevant biomarkers are identified. Toward this end, we demonstrate the detection of SARS-CoV-2 neutralizing antibodies in ISF collected from COVID-19 vaccinees using two commercial immunoassays, showcasing the utility of this technique for diagnostic testing.
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    Microneedle-based skin patch for blood-free rapid diagnostic testing
    (Springer Nature, 2020) Jiang, Xue; Lillehoj, Peter B.
    Rapid diagnostic tests are one of the most commonly used tests to detect and screen for infectious diseases in the developing world. While these tests are simple, inexpensive, and readily available, they rely on finger-prick blood sampling, which requires trained medical personnel, poses risks of infection, and can complicate cooperation in young children, asymptomatic individuals, and communities with blood taboos. Here, we report a novel microneedle-based skin patch for the rapid detection of protein biomarkers in dermal interstitial fluid. Sample collection is facilitated by a hydrophilic hollow microneedle array that autonomously extracts and transports interstitial fluid to an antibody-based lateral flow test strip via surface tension for colorimetric antigen detection. We employ a simple gold enhancement treatment to enhance the detection sensitivity of this colloidal gold-based lateral flow assay and elucidate the underlying mechanism of this enhancement mechanism through experimental investigation. For proof-of-concept, this device was used to detect Plasmodium falciparum histidine-rich protein 2, a biomarker for malaria infection, which could be detected at concentrations as low as 8 ng/mL. Each test can be completed in <20 min and requires no equipment. To the best of our knowledge, this work is the first demonstration of a microneedle-based lateral flow assay for rapid protein detection in dermal interstitial fluid. In addition to its simplicity, minimally invasive nature, and low cost, this diagnostic device can be readily adapted to detect other protein biomarkers in interstitial fluid, making it a promising tool for point-of-care testing.