Quantitative Detection in the Attomole Range for Immunochromatographic Tests by Means of a Flatbed Scanner

✍ Scribed by Maria Lönnberg; Jan Carlsson

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 133 KB
• Volume: 293
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1006/abio.2001.5130

✦ Synopsis

This work describes the use of the combination of carbon black as an antibody label, a membrane-based immunochromatographic device, and a flatbed scanner as a quantitative test system. The scanner detected 0.4 -345 ng carbon black/mm 2 on a nitrocellulose membrane (0.2-170 amol carbon black/mm 2 ) with an imprecision (coefficient of variation, CV) lower than 2% for the carbon black determination and a detection limit of 0.04 ng carbon black/mm 2 (0.02 amol/mm 2 ). The detection ability was compared to that obtained with alkaline phosphatase (ALP) using a substrate yielding a chemiluminescent signal (0.02 amol ALP/well), ␤-galactosidase using a substrate yielding a fluorescent signal (0.3 amol ␤-galactosidase/well), and horseradish peroxidase (HRP) using a substrate yielding a colored signal (5 amol HRP/microtiter well). The carbon black immunochromatographic test for immunoglobulin E (IgE) showed a detection limit of 0.13 pM IgE (0.01 kU/L) after a testing time of 10 min. The scanner detection imprecision for the IgE determination was 0.6% CV in the range 1-10 kU IgE/L when 2.3 mm 2 was used for detection and 1% CV when 0.19 mm 2 was used. A flatbed scanner is an inexpensive instrument with multiple uses, which now also includes the sensitive evaluation of immunoassays.