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Updated: Jul 10, 2026

Highly Sensitive and Quantitative Detection of Proteins and Their Isoforms by Capillary Isoelectric Focusing Method
Published on: September 19, 2018
Laser-induced fluorescence detector for capillary-based isoelectric immunoblot assay
James E Knittle1, David Roach, Peter B Vander Horn
1Cell Biosciences, Inc., 1050 Page Mill Road, Palo Alto, California 94304, USA. jknittle@cellbiosciences.com
Abstract:
We describe a whole-capillary, multicolor laser-induced fluorescence scanner for microfluidic protein analysis systems. Separation of proteins is achieved by isoelectric focusing in a short length of fused-silica capillary after which the resolved proteins are immobilized to the capillary wall using photochemistry. The capillary is then evacuated, and fluorescently labeled antibodies are flowed through the capillary to bind to the immobilized proteins. This technique provides high sensitivity, the ability to spatially resolve and quantify proteins, and provides the opportunity for complete automation. Results obtained by fluorescence detection are compared to those obtained by chemiluminescence while offering enhanced resolution and signal stability.
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