A single-step enzyme immunoassay capillary sensor composed of functional multilayer coatings for the diagnosis of marker proteins

• Published in: Analyst (London) Vol. 140; no. 5; pp. 1459 - 1465
• Main Authors: Funano, Shun-ichi, Sugahara, Masato, Henares, Terence G, Sueyoshi, Kenji, Endo, Tatsuro, Hisamoto, Hideaki
• Format: Journal Article
• Language: English
• Published: England 07.03.2015
• Subjects: alpha-Fetoproteins - analysis; Antibodies; Antigen-Antibody Complex; Antigens; Biomarkers - analysis; C-Reactive Protein - analysis; Capillarity; Coatings; Electrophoresis, Capillary - methods; Enzymes; Glycated Hemoglobin A - analysis; Humans; Hydrogel, Polyethylene Glycol Dimethacrylate - chemistry; Hydrogels; Immunoenzyme Techniques - methods; Markers; Proteins; Sensors
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/c4an01781a

A single-step, easy-to-use enzyme immunoassay capillary sensor, composed of functional multilayer coatings, was developed in this study. The coatings were composed of substrate-immobilized hydrophobic coating, hydrogel coating, and soluble coating containing an enzyme-labeled antibody. The response mechanism involved a spontaneous immunoreaction triggered by capillary action-mediated introduction of a sample antigen solution and subsequent separation of unreacted enzyme-labeled antibodies and antigen-enzyme-labeled antibody complexes by the molecular sieving effect of the hydrogel. An enzyme reaction at the substrate-immobilized hydrophobic coating/hydrogel coating interface resulted in a protein-selective fluorescence response. An antigen concentration-dependent response was obtained for diagnostic marker protein samples (hemoglobin A1c (HbA1c), 7.14-16.7 mg mL(-1); alpha-fetoprotein (AFP), 1.4-140 ng mL(-1); C-reactive protein (CRP), 0.5-10 μg mL(-1)) that cover a clinically important concentration range. The successful measurement of CRP in diluted serum samples demonstrated the application of this capillary sensor.