Isoelectric focusing of fibrinogens on polyacrylamide gels

Krantz, S; Lober, M; Fiedler, H

doi:10.1016/0014-5793(70)80501-4

Cited by 9 publications

(2 citation statements)

References 6 publications

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“…In order to provide a measure of patients' glucose levels over intermediate time intervals (2-3 weeks), the fructosamine assay has emerged recently as a complimentary technique. [56][57][58][59][60][61] A commonly used and commercially available colorimetric fructosamine assay generates formazan as an end-product, which has significant absorbance in the 500-650 nm range (maximum absorbance at 570 nm). Considering that the green LED in our system has a spectral output between 500 and 600 nm that overlaps well with that of formazan (see inset of Fig.…”

Section: Fructosamine Quantification In Standards and Serum Samplesmentioning

confidence: 99%

Droplet-based μChopper device with a 3D-printed pneumatic valving layer and a simple photometer for absorbance based fructosamine quantification in human serum

Kayirangwa,

Mohibullah,

Easley

2023

Analyst

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Section: Fructosamine Quantification In Standards and Serum Samplesmentioning

confidence: 99%

Droplet-based μChopper device with a 3D-printed pneumatic valving layer and a simple photometer for absorbance based fructosamine quantification in human serum

Kayirangwa,

Mohibullah,

Easley

2023

Analyst

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show abstract

“…In order to provide a measure of patients' glucose levels over intermediate time intervals (2-3 weeks), the fructosamine assay has emerged recently as a complimentary technique [56][57][58][59][60][61] . A commonly used and commercially available colorimetric fructosamine assay generates formazan as an end-product, which has significant absorbance in the 500-650 nm range (maximum absorbance at 570 nm).…”

Section: Fructosamine Quantification In Standards and Serum Samplesmentioning

confidence: 99%

Droplet-based µChopper device with a 3D-printed pneumatic valving layer and a simple photometer for absorbance based fructosamine quantification in human serum

Kayirangwa,

Mohibullah,

Easley

2023

Preprint

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The development of microfluidic systems for biological assays presents challenges, particularly in adapting traditional optical absorbance assays to smaller volumes or to microfluidic formats. This often requires assay modification or translation to a fluorescence version, which can be impractical. To address this issue, our group has developed the µChopper device, which uses microfluidic droplet formation as a surrogate for an optical beam chopper, allowing for lock-in analysis and improved limits of detection with both absorbance and fluorescence optics without modifying the optical path length. Here, we have adapted the µChopper to low-cost optics using a light-emitting diode (LED) source and photodiode detector, and we have fabricated the pnuematically valved devices entirely by 3D printing instead of traditional photolithography. Using a hybrid device structure, fluidic channels were made in polydimethylsiloxane (PDMS) by moulding onto a 3D-printed master then bonding to a prefabricated thin layer, and the pneumatic layer was directly made of 3D-printed resin. This hybrid structure allowed an optical slit to be fabricated directly under fluidic channels, with the LED interfaced closely above the channel. Vacuum-operated, normally closed valves provided precise temporal control of droplet formation from 0.6 to 2.0 Hz. The system was validated against the standard plate reader format using a colorimetric fructosamine assay and by quantifying fructosamine in human serum from normal and diabetic patients, where strong correlation was shown. Showing a standard benefit of microfluidics in analysis, the device required 6.4-fold less serum volume for each assay. This µChopper device and lower cost optical system should be applicable to various absorbance based assays in low volumes, and the reliance on inexpensive 3D printers makes it more accessible to users without cleanroom facilities.

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Antihypertensive Role of Kidney: Focus on Tissue Kallikreins

Mandal

Chakraborti

2017

Pathophysiological Aspects of Proteases

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Isoelectric focusing of fibrinogens on polyacrylamide gels

Cited by 9 publications

References 6 publications

Droplet-based μChopper device with a 3D-printed pneumatic valving layer and a simple photometer for absorbance based fructosamine quantification in human serum

Droplet-based μChopper device with a 3D-printed pneumatic valving layer and a simple photometer for absorbance based fructosamine quantification in human serum

Droplet-based µChopper device with a 3D-printed pneumatic valving layer and a simple photometer for absorbance based fructosamine quantification in human serum

Antihypertensive Role of Kidney: Focus on Tissue Kallikreins

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