Lee L.G.,Song Diagnostic Research, Llc |
Nordman E.S.,Song Diagnostic Research, Llc |
Johnson M.D.,Song Diagnostic Research, Llc |
Oldham M.F.,Song Diagnostic Research, Llc
Biosensors | Year: 2013
We demonstrate a fluorescence lateral flow system that has excellent sensitivity and wide dynamic range. The illumination system utilizes an LED, plastic lenses and plastic and colored glass filters for the excitation and emission light. Images are collected on an iPhone 4. Several fluorescent dyes with long Stokes shifts were evaluated for their signal and nonspecific binding in lateral flow. A wide range of values for the ratio of signal to nonspecific binding was found, from 50 for R-phycoerythrin (R-PE) to 0.15 for Brilliant Violet 605. The long Stokes shift of R-PE allowed the use of inexpensive plastic filters rather than costly interference filters to block the LED light. Fluorescence detection with R-PE and absorbance detection with colloidal gold were directly compared in lateral flow using biotinylated bovine serum albumen (BSA) as the analyte. Fluorescence provided linear data over a range of 0.4-4,000 ng/mL with a 1,000-fold signal change while colloidal gold provided non-linear data over a range of 16-4,000 ng/mL with a 10-fold signal change. A comparison using human chorionic gonadotropin (hCG) as the analyte showed a similar advantage in the fluorescent system. We believe our inexpensive yet high-performance platform will be useful for providing quantitative and sensitive detection in a point-of-care setting. © 2013 by the authors.
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 134.68K | Year: 2014
DESCRIPTION (provided by applicant): Dengue is the most rapidly spreading mosquito-borne virus in the world and currently infects 390 million people annually. Studies have shown that existing point-of-care tests have inadequate sensitivity to identify manyindividuals infected with dengue. None have the quantitative capability necessary to aid in the detection of severe dengue, especially in secondary dengue infections. Our approach will provide a low-cost yet quantitative and sensitive system. Our lateralflow immunoassay (LFIA) test will analyze and quantitate the presence of dengue virus non-structural protein (DENV NS1), an analyte that is frequently used to determine a diagnosis of dengue. Fluorescent dyes will be used to improve the limit of detectioncompared to existing rapid tests. A smart phone is utilized for imaging, analysis and automated reporting; the latter feature will simplify disease tracking. A long Stokes shift dye, R-phycoerythrin (PE) will be used as the fluorescent reporter, eith
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 150.00K | Year: 2014
DESCRIPTION (provided by applicant): Each year, 1.5 million children are born to mothers living with HIV resulting in vertical transmission of HIV to newborns in 350,000 cases. Early testing followed by prompt anti-retroviral therapy (ART) is known to savelives, yet lack of point-of-care (POC) tests for infants results in delays or absence of therapy. Our approach will provide a low-cost yet quantitative and sensitive lateral flow immunoassay (LFIA) test to analyze and quantitate the presence of HIV p24.Fluorescent dyes will be used to improve the limit of detection compared to existing rapid tests. A smart phone is utilized for imaging, analysis and automated reporting. A long Stokes shift dye, R-phycoerythrin (PE) will be used as the fluorescent reporter, either singly or bundled into a cluster. The optical properties of PE allow the use of an inexpensive illumination device; the minimal non-specific binding of PE results in sensitive detection with a wide dynamic range. Additional gains in sensitiv
Song Diagnostic Research, Llc | Date: 2014-10-09
Lateral flow test strips, systems, and methods are provided for measuring the presence and levels of analytes in samples in which the analyte may be complexed, for example within an analyte-antibody complex. Test strips are provided that can decomplex the analyte from the analyte-antibody complex during the lateral flow assay, resulting in high quality assays without the need for a decomplexation pre-treatment step. Various systems and methods for improving the performance of lateral flow assays are described, which include minimization of the Prozone effect, improved dynamic range, improving sensitivity by disrupting complexation of target antigens. The resulting lateral flow system has improved sensitivity and improved dynamic range, and may utilize fluorescence. The illumination system utilizes an LED, plastic lenses and plastic and colored glass filters for the excitation and emission light.