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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

Photobleaching of R-PE streptavidin (pink) and Alexa Fluor 532 streptavidin (blue). The compounds were spotted on nitrocellulose and exposed to constant illumination with a 505 nm LED. Images were collected at time intervals. (a) Data was normalized to the initial values; (b) A plot of the natural logarithm of the signal. Half-lives were determined by the equation t1/2 = ln2/k, where k is the negative slope of the natural log plot.
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biosensors-03-00360-f010: Photobleaching of R-PE streptavidin (pink) and Alexa Fluor 532 streptavidin (blue). The compounds were spotted on nitrocellulose and exposed to constant illumination with a 505 nm LED. Images were collected at time intervals. (a) Data was normalized to the initial values; (b) A plot of the natural logarithm of the signal. Half-lives were determined by the equation t1/2 = ln2/k, where k is the negative slope of the natural log plot.

Mentions: R-PE is reported to be less photostable than organic dyes. We tested the stability in our breadboard by illuminating spots of R-PE streptavidin and spots of Alexa Fluor streptavidin and recording the loss of signal over time. Figure 10 shows plots of signal vs. time for both dyes as a percentage of the initial signal and the natural logarithm of the signal. Under constant LED illumination, Alexa Fluor 532 is more stable (t½ = 7,000 s) than R-PE (t½ = 2,000 s). Both are expected to be sufficiently stable under normal storage conditions of lateral flow strips.


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

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

Photobleaching of R-PE streptavidin (pink) and Alexa Fluor 532 streptavidin (blue). The compounds were spotted on nitrocellulose and exposed to constant illumination with a 505 nm LED. Images were collected at time intervals. (a) Data was normalized to the initial values; (b) A plot of the natural logarithm of the signal. Half-lives were determined by the equation t1/2 = ln2/k, where k is the negative slope of the natural log plot.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

biosensors-03-00360-f010: Photobleaching of R-PE streptavidin (pink) and Alexa Fluor 532 streptavidin (blue). The compounds were spotted on nitrocellulose and exposed to constant illumination with a 505 nm LED. Images were collected at time intervals. (a) Data was normalized to the initial values; (b) A plot of the natural logarithm of the signal. Half-lives were determined by the equation t1/2 = ln2/k, where k is the negative slope of the natural log plot.
Mentions: R-PE is reported to be less photostable than organic dyes. We tested the stability in our breadboard by illuminating spots of R-PE streptavidin and spots of Alexa Fluor streptavidin and recording the loss of signal over time. Figure 10 shows plots of signal vs. time for both dyes as a percentage of the initial signal and the natural logarithm of the signal. Under constant LED illumination, Alexa Fluor 532 is more stable (t½ = 7,000 s) than R-PE (t½ = 2,000 s). Both are expected to be sufficiently stable under normal storage conditions of lateral flow strips.

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