Capillary electrophoresis immunoassay using magnetic beads.
Protein A-coated magnetic beads (0.3 mum) have been trapped in a small portion of a neutrally coated capillary (50 mum id). Anti-beta-lactoglobulin (beta-LG) antibodies have then been immobilized on the beads through strong affinity with protein A to subsequently capture beta-LG from model or real samples. Once the immunocomplexes formed at physiological pH, a discontinuous buffer system has been used to release the partners and preconcentrate them by transient ITP. The antigens and antibodies have finally been separated by CZE and detected by UV absorbance. An LOQ of 55 nM has been achieved. This methodology has been applied to quantify native beta-LG in pasteurized and ultra-high-temperature-treated bovine milk. All the described procedures, including immunosorbent preparation, sample extraction, cleanup, preconcentration, and separation are completely automated on a commercial CE instrument. As this CE immunoassay method is simple, rapid, selective, and sensitive, it should be a practical and attractive technology for the analysis of complicated biological samples.
Chen
Hong-Xu
HX
Laboratoire d'Electrochimie Physique et Analytique, EPFL SB ISIC LEPA, Lausanne, Switzerland.
Busnel
Jean-Marc
JM
Gassner
Anne-Laure
AL
Peltre
Gabriel
G
Zhang
Xin-Xiang
XX
Girault
Hubert H
HH
D000906:Antibodies / Q000276:immunology*; D019075:Electrophoresis, Capillary / Q000379:methods; D007118:Immunoassay; D018189:Immunomagnetic Separation / Q000379:methods; D007782:Lactoglobulins / Q000032:analysis / Q000276:immunology*; D013205:Staphylococcal Protein A / Q000276:immunology
D000906:Antibodies; D007782:Lactoglobulins; D013205:Staphylococcal Protein A