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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.


Layout of optics breadboard.
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biosensors-03-00360-f002: Layout of optics breadboard.

Mentions: To facilitate easy setup modification and allow use of 1″ optics and filters the optics breadboard (BB) was constructed using 30 mm cage components (Thorlabs, Newton, NJ, USA). The cage components were secured to an aluminum plate positioning optics as shown in Figure 1, allowing motion of one plate to clamp the smartphone. The excitation source was a 505 nm LED providing 122 lm at 700 mA (SR-01-E0070, Quandrica Developments, Brantford, ON, Canada). The LED current was controlled by a 700 mA externally dimmable DC driver (A011-D-V-700, LEDdynamics Quandrica Developments) powered by eight AA batteries with holder (Mouser Electronics). A 20 KΩ potentiometer (652-3386P-1-203LF, Mouser Electronics) was used to control the LED current (normally set to full (700 mA) except when setting exposure). A power switch (611-CA22J72207PQ, Mouser Electronics) was provided to prevent draining of the batteries when not in use. The LED was mounted to the cage support endplate using precut thermal adhesive tape (LXT-S-12, Quandrica Developments) with a 7°, 11 mm reflector (Dialight). The excitation filter was provided by two 0.003″ thick plastic films (Supergel #69 brilliant blue, Rosco). The excitation beam was focused using a 25 mm diameter, 25 mm FL acrylic lens (NT48-170, Edmund Optics). A schematic of the optics breadboard for analysis of the lateral flow assay (LFA) and dot blots is shown in Figure 2.


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

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

Layout of optics breadboard.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

biosensors-03-00360-f002: Layout of optics breadboard.
Mentions: To facilitate easy setup modification and allow use of 1″ optics and filters the optics breadboard (BB) was constructed using 30 mm cage components (Thorlabs, Newton, NJ, USA). The cage components were secured to an aluminum plate positioning optics as shown in Figure 1, allowing motion of one plate to clamp the smartphone. The excitation source was a 505 nm LED providing 122 lm at 700 mA (SR-01-E0070, Quandrica Developments, Brantford, ON, Canada). The LED current was controlled by a 700 mA externally dimmable DC driver (A011-D-V-700, LEDdynamics Quandrica Developments) powered by eight AA batteries with holder (Mouser Electronics). A 20 KΩ potentiometer (652-3386P-1-203LF, Mouser Electronics) was used to control the LED current (normally set to full (700 mA) except when setting exposure). A power switch (611-CA22J72207PQ, Mouser Electronics) was provided to prevent draining of the batteries when not in use. The LED was mounted to the cage support endplate using precut thermal adhesive tape (LXT-S-12, Quandrica Developments) with a 7°, 11 mm reflector (Dialight). The excitation filter was provided by two 0.003″ thick plastic films (Supergel #69 brilliant blue, Rosco). The excitation beam was focused using a 25 mm diameter, 25 mm FL acrylic lens (NT48-170, Edmund Optics). A schematic of the optics breadboard for analysis of the lateral flow assay (LFA) and dot blots is shown in Figure 2.

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.