Monodisperse Carboxyl-Functionalized Poly(Ethylene Glycol)-Coated Magnetic Poly(Glycidyl Methacrylate) Microspheres: Application to the Immunocapture of β-Amyloid Peptides

Identification and evaluation of small changes in beta-amyloid peptide (A beta) levels in cerebrospinal fluid is of crucial importance for early detection of Alzheimer's disease. Microfluidic detection methods enable effective preconcentration of Ab using magnetic microparticles coated with Ab antibodies. Poly-(glycidyl methacrylate) microspheres are coated with alpha-amino-omega-methoxy-PEG(5000)/alpha-amino-omega-Boc-NH-PEG(5000) Boc groups deprotected and NH2 succinylated to introduce carboxyl groups. Capillary electrophoresis with laser-induced fluorescence detection confirms the efficient capture of A beta 1-40 peptides on the microspheres with immobilized monoclonal anti-A beta 6E10. The capture specificity is confirmed by comparing A beta 1-40 levels on the anti-IgG-immobilized particles used as a control.