Minimum-step immuno-analysis based on continuous recycling of the capture antibody

• Published in: Analyst (London) Vol. 136; no. 7; pp. 1374 - 1379
• Main Authors: CHO, Hyun-Kyu, SEO, Sung-Min, CHO, Il-Hoon, PAEK, Sung-Ho, KIM, Dong-Hyung, PAEK, Se-Hwan
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 07.04.2011
• Subjects: alpha-Macroglobulins - analysis; Analytical chemistry; Antibodies, Immobilized - chemistry; Antibodies, Immobilized - immunology; Antibodies, Monoclonal - chemistry; Antibodies, Monoclonal - immunology; Chemistry; Exact sciences and technology; General, instrumentation; Humans; Immunoassay - methods; Microfluidic Analytical Techniques - methods; Protein Binding; Fold; Fluid mechanics; On line; Antibody; Size; Use; Immobilization; Time; Concentration; Chemical sensor; Capture; Antigen; Target; Cover; Dynamics; Affinity; Serum; Recycling; Sampling; Microfluidics; Monitoring
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/c0an00811g

Most immuno-analytical systems employ antibodies that do not readily dissociate upon binding to its partner antigen (i.e., target analyte; α2-macroglobulin as a model) and, thus, either need to be disposed of after one-time use or be reused after binding has been reset. To achieve a minimum-step analysis, an antibody that is capable of rapidly reversible binding with high affinity to an antigen was investigated in this study. This antibody was immobilized on the surface of a label-free sensor, which was combined with microfluidic channels, to demonstrate its applicability. The antibody was successively reused without a regeneration step under physiological conditions, offered specific analysis in the serum medium, and detected the analyte at concentrations as low as 0.1 ng mL(-1), which could further be enhanced by 100-fold. The sensor response reached 95% equilibrium after 8.3 and 14.9 min in average on each dose level for the concentration increase and decrease, respectively. The dynamic range covered a 5 logarithmic analyte concentration. Since the sampling size was in the nanolitre to millilitre range per day under the conditions used and the sensor may retain a long shelf-life, it could potentially be used in a clinical setting for long-term, on-line monitoring of diseases.