BACKGROUND: We explored the potential of a microfluidic device based on centrifugal force as an immunoassay platform by examining the imprecision of assays carried out with 200 nL of sample. METHODS: Biotinylated antibodies against alpha-fetoprotein (AFP), interleukin-6 (IL-6), and carcinoembryonic antigen [(CEA); 0.1 g/L each in 15 mmol/L phosphate-buffered saline (PBS) containing 0.1 mL/L Tween 20] were attached to a microcolumn packed with streptavidin-coated particles. A 200-nL sample was then allowed to pass through the microcolumn for 240 s, followed by Alexa 647-labeled detection antibody (7.5 mg/L in 15 mmol/L PBS containing 10 g/L bovine serum albumin). The flow rate was controlled by altering the rotational speed. Up to 104 sandwich type immunoassays were completed within 50 min. RESULTS: For AFP, IL-6, and CEA the detection limits were, respectively, 0.15, 1.25, and 1.31 pmol/L. Inter- and intraassay imprecisions (CVs) were <10% and <20%, respectively, for analyte concentrations >5 pmol/L. The CEA antibody had the lowest affinity according to fluorescence image analysis of the microcolumn region. The result was confirmed in a comparative study using BIAcore 3000. CONCLUSIONS: Day-to-day (total) imprecision (CV) of immunoassays on the compact disc-shaped device are <20%. Analysis of fluorescence images allows rapid ranking of antibodies according to their affinities.
BACKGROUND: We explored the potential of a microfluidic device based on centrifugal force as an immunoassay platform by examining the imprecision of assays carried out with 200 nL of sample. METHODS: Biotinylated antibodies against alpha-fetoprotein (AFP), interleukin-6 (IL-6), and carcinoembryonic antigen [(CEA); 0.1 g/L each in 15 mmol/L phosphate-buffered saline (PBS) containing 0.1 mL/L Tween 20] were attached to a microcolumn packed with streptavidin-coated particles. A 200-nL sample was then allowed to pass through the microcolumn for 240 s, followed by Alexa 647-labeled detection antibody (7.5 mg/L in 15 mmol/L PBS containing 10 g/L bovine serum albumin). The flow rate was controlled by altering the rotational speed. Up to 104 sandwich type immunoassays were completed within 50 min. RESULTS: For AFP, IL-6, and CEA the detection limits were, respectively, 0.15, 1.25, and 1.31 pmol/L. Inter- and intraassay imprecisions (CVs) were <10% and <20%, respectively, for analyte concentrations >5 pmol/L. The CEA antibody had the lowest affinity according to fluorescence image analysis of the microcolumn region. The result was confirmed in a comparative study using BIAcore 3000. CONCLUSIONS: Day-to-day (total) imprecision (CV) of immunoassays on the compact disc-shaped device are <20%. Analysis of fluorescence images allows rapid ranking of antibodies according to their affinities.
Authors: Andres W Martinez; Scott T Phillips; Emanuel Carrilho; Samuel W Thomas; Hayat Sindi; George M Whitesides Journal: Anal Chem Date: 2008-04-11 Impact factor: 6.986
Authors: Gayan C Bandara; Linus J Unitan; Matthew H Kremer; Owen T Shellhammer; Shay Bracha; Vincent T Remcho Journal: Anal Bioanal Chem Date: 2021-05-27 Impact factor: 4.142
Authors: Emil P Kartalov; David H Lin; David T Lee; William F Anderson; Clive R Taylor; Axel Scherer Journal: Electrophoresis Date: 2008-12 Impact factor: 3.535