Noncompetitive Fluorescence Polarization Immunoassay for Protein Determination
Mao Fukuyama1, Ayano Nakamura2, Keine Nishiyama2
1Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.
Abstract:
Fluorescent polarization immunoassay (FPIA) is a single-step immunoassay method that is applicable to point-of-care testing; however, its applicability to large biomolecules has been restricted because ordinary FPIA is a competitive assay. Here, we report a noncompetitive FPIA using the variable domain from the heavy chain of a camelid antibody (VHH antibody). FPIA with VHH was successfully used to quantitate rabbit immunoglobulin G (IgG) and demonstrated a wider response range than that observed with antibody-binding (Fab) fragment. Then, using a portable FPIA instrument, a VHH-based immunoassay of human IgG in a human serum certified reference material was demonstrated.
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