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A low-cost, high-performance system for fluorescence lateral flow assays.

Lee LG, Nordman ES, Johnson MD, Oldham MF - Biosensors (Basel) (2013)

Bottom Line: 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.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.We believe our inexpensive yet high-performance platform will be useful for providing quantitative and sensitive detection in a point-of-care setting.

View Article: PubMed Central - PubMed

Affiliation: Song Diagnostic Research LLC, 1 Megans Lane, Woodside, CA 94062, USA. Linda@songdx.net.

ABSTRACT
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.

No MeSH data available.


Schematic of a lateral flow assay with colloidal gold as label.
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biosensors-03-00360-f001: Schematic of a lateral flow assay with colloidal gold as label.

Mentions: Lateral flow technology [1] is used for the detection of proteins, viral antigens and small molecules and enables rapid point-of-care diagnostics of infectious diseases (malaria [2], dengue [3,4], and HIV [5]) as well as cardiac markers (troponin [6]) and cancer biomarkers (prostate specific antigen [7]). The format utilizes a sandwich immunoassay: two antibodies are ultimately bound to an analyte in a sandwich fashion. One antibody (mAb) is initially bound non-covalently in a horizontal stripe on a narrow strip of nitrocellulose. The nitrocellulose is blocked with protein to prevent nonspecific adherence of analyte and other proteins, and the analyte and a second, labeled antibody (typically labeled with colloidal gold) is allowed to flow up the nitrocellulose. A “sandwich” of the analyte and the two antibodies forms on the stripe and appears as a visible, reddish line. Typically, an absorbent pad containing the gold-labeled antibody is used to deliver the reagent, and a control line containing antibody to the Fc portion of the gold-labeled antibody is located upstream of the test line. A diagram of the process is illustrated in Figure 1.


A low-cost, high-performance system for fluorescence lateral flow assays.

Lee LG, Nordman ES, Johnson MD, Oldham MF - Biosensors (Basel) (2013)

Schematic of a lateral flow assay with colloidal gold as label.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263565&req=5

biosensors-03-00360-f001: Schematic of a lateral flow assay with colloidal gold as label.
Mentions: Lateral flow technology [1] is used for the detection of proteins, viral antigens and small molecules and enables rapid point-of-care diagnostics of infectious diseases (malaria [2], dengue [3,4], and HIV [5]) as well as cardiac markers (troponin [6]) and cancer biomarkers (prostate specific antigen [7]). The format utilizes a sandwich immunoassay: two antibodies are ultimately bound to an analyte in a sandwich fashion. One antibody (mAb) is initially bound non-covalently in a horizontal stripe on a narrow strip of nitrocellulose. The nitrocellulose is blocked with protein to prevent nonspecific adherence of analyte and other proteins, and the analyte and a second, labeled antibody (typically labeled with colloidal gold) is allowed to flow up the nitrocellulose. A “sandwich” of the analyte and the two antibodies forms on the stripe and appears as a visible, reddish line. Typically, an absorbent pad containing the gold-labeled antibody is used to deliver the reagent, and a control line containing antibody to the Fc portion of the gold-labeled antibody is located upstream of the test line. A diagram of the process is illustrated in Figure 1.

Bottom Line: 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.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.We believe our inexpensive yet high-performance platform will be useful for providing quantitative and sensitive detection in a point-of-care setting.

View Article: PubMed Central - PubMed

Affiliation: Song Diagnostic Research LLC, 1 Megans Lane, Woodside, CA 94062, USA. Linda@songdx.net.

ABSTRACT
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.

No MeSH data available.