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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.


Related in: MedlinePlus

Fluorescence lateral flow images and plot. A spot rather than the conventional stripe of streptavidin was applied to the nitrocellulose. The spot diameter was approximately 3 mm. Dilutions of biotinylated BSA, followed by R-PE streptavidin, followed by buffer were absorbed onto the strips. Each concentration was tested in triplicate. Images were obtained in a breadboard equipped with an iPhone 4 and ProCamera app; a sample of the images is shown on the right. Image analysis was done with Image J and the results plotted.
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biosensors-03-00360-f006: Fluorescence lateral flow images and plot. A spot rather than the conventional stripe of streptavidin was applied to the nitrocellulose. The spot diameter was approximately 3 mm. Dilutions of biotinylated BSA, followed by R-PE streptavidin, followed by buffer were absorbed onto the strips. Each concentration was tested in triplicate. Images were obtained in a breadboard equipped with an iPhone 4 and ProCamera app; a sample of the images is shown on the right. Image analysis was done with Image J and the results plotted.

Mentions: Figure 6 shows the results of a fluorescence lateral flow assay that utilized a sandwich system of streptavidin, biotinylated BSA, and R-PE-labeled streptavidin. Streptavidin was spotted down on the strips and allowed to dry. A four-fold dilution series of biotinylated BSA in 1% BSA was prepared. Each strip was dipped successively into 20 µL of the dilution series, then into 20 µL of R-PE streptavidin, and finally into 50 µL 1% BSA. After drying the strips were imaged. The images are a crescent shape rather than a filled-in spot, showing that the streptavidin-biotin-RPE-streptavidin sandwich is formed at the leading edge of the spot, or as soon as the eluting reagents enter the “test” zone.


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

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

Fluorescence lateral flow images and plot. A spot rather than the conventional stripe of streptavidin was applied to the nitrocellulose. The spot diameter was approximately 3 mm. Dilutions of biotinylated BSA, followed by R-PE streptavidin, followed by buffer were absorbed onto the strips. Each concentration was tested in triplicate. Images were obtained in a breadboard equipped with an iPhone 4 and ProCamera app; a sample of the images is shown on the right. Image analysis was done with Image J and the results plotted.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

biosensors-03-00360-f006: Fluorescence lateral flow images and plot. A spot rather than the conventional stripe of streptavidin was applied to the nitrocellulose. The spot diameter was approximately 3 mm. Dilutions of biotinylated BSA, followed by R-PE streptavidin, followed by buffer were absorbed onto the strips. Each concentration was tested in triplicate. Images were obtained in a breadboard equipped with an iPhone 4 and ProCamera app; a sample of the images is shown on the right. Image analysis was done with Image J and the results plotted.
Mentions: Figure 6 shows the results of a fluorescence lateral flow assay that utilized a sandwich system of streptavidin, biotinylated BSA, and R-PE-labeled streptavidin. Streptavidin was spotted down on the strips and allowed to dry. A four-fold dilution series of biotinylated BSA in 1% BSA was prepared. Each strip was dipped successively into 20 µL of the dilution series, then into 20 µL of R-PE streptavidin, and finally into 50 µL 1% BSA. After drying the strips were imaged. The images are a crescent shape rather than a filled-in spot, showing that the streptavidin-biotin-RPE-streptavidin sandwich is formed at the leading edge of the spot, or as soon as the eluting reagents enter the “test” zone.

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.


Related in: MedlinePlus