Abstract
Detection and accurate quantitation of biomarkers such as r-fetoprotein (AFP) can be a key aspect of early stage cancer diagnosis. Microfluidic devices provide attractive analysis capabilities, including low sample and reagent consumption, as well as short assay times. However, to date microfluidic analyzers have relied almost exclusively on calibration curves for sample quantitation, which can be problematic for complex mixtures such as human serum. We have fabricated integrated polymer microfluidic systems that can quantitatively determine fluorescently labeled AFP in human serum using either the method of standard addition or a calibration curve. Our microdevices couple an immunoaf-finity purification step with rapid microchip electrophoresis separation in a laser-induced fluorescence detection system, all under automated voltage control in a miniaturized polymer microchip. In conjunction with laser-induced fluorescence detection, these systems can quantify AFP at ∼1 ng/mL levels in ∼10 μL of human serum in a few tens of minutes. Our polymer microdevices have been applied in determining AFP in spiked serum samples. These integrated microsystems offer excellent potential for rapid, simple, and accurate biomarker quantitation in a point-of-care setting. © 2009 American Chemical Society.