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

Abstract

Identification and evaluation of small changes in β-amyloid peptide (Aβ) levels in cerebrospinal fluid is of crucial importance for early detection of Alzheimer's disease. Microfluidic detection methods enable effective preconcentration of Aβ using magnetic microparticles coated with Aβ antibodies. Poly(glycidyl methacrylate) microspheres are coated with α-amino-ω-methoxy-PEG5000 /α-amino-ω-Boc-NH-PEG5000 Boc groups deprotected and NH2 succinylated to introduce carboxyl groups. Capillary electrophoresis with laser-induced fluorescence detection confirms the efficient capture of Aβ 1-40 peptides on the microspheres with immobilized monoclonal anti-Aβ 6E10. The capture specificity is confirmed by comparing Aβ 1-40 levels on the anti-IgG-immobilized particles used as a control.

Evaluation of poly(ethylene glycol)-coated monodispersed magnetic poly(2-hydroxyethyl methacrylate) and poly(glycidyl methacrylate) microspheres by PCR

“…More carboxyl groups on the particles correspond to higher PCR inhibition. This result is consistent with previous reports, where nonspecific protein sorption is directly proportional to the concentration of carboxyl groups in the support [42,47]. The PEG 5000 -mgtPGMA-18 microspheres that are coated under the cloud point conditions have high reaction efficiency and only slightly inhibit the DNA amplification.…”

“…The wavenumbers ranged from 4400 to 450 cm À1 , the resolution was 4 cm À1 , and 64 scans were performed. Undesirable nonspecific adsorption on the microspheres was experimentally checked with bovine serum albumin (BSA), radiolabeled 125 I-BSA, c-globulin, fibrinogen, pepsin and chymotrypsin as described in a previous paper [42]. generated by performing qPCR with a 10-fold serial dilution of E. coli DNA (100 ng ll À1 -1 pg ll À1 ) were analyzed in each plate.…”

“…1d). The particle surface was analyzed in more details using more advanced techniques, such as AFM, which displays dense surface PEG coverage on both PEG 5000 -mgtPGMA-1.8 and PEG 5000 -mgtPGMA-18 microspheres [42]. The number-average diameters D n of PEGylated mgtPHEMA and mgtPGMA microspheres slightly increase (Table 1).…”

“…The MCMEMA moiety of both particles was hydrolyzed with NaOH to provide them with carboxyl groups. To render the particles with magnetic properties, the iron oxide was precipitated in the particle pores to produce magnetic PHEMA (mgtPHEMA) and magnetic PGMA microspheres (mgtPGMA) [42]. To reduce the undesirable nonspecific protein adsorption on the magnetic microspheres, they were modified with poly(ethylene glycol)s (PEG) of various molecular weights (M w = 2000 and 5000) using EDC/NHS chemistry [43].…”

Detection of Aβ Monomers and Oligomers: Early Diagnosis of Alzheimer's Disease

“…Hence, this methodh as the potentialtor ealize the diagnostic specificity of AD by using multiple biomarkers, facilitatingt he clinical development of neurodegenerative diseases.C E-LIF wasa lso used to measure the Ab 1-40 level in combinationw ith am icrofluidic detection methodb ecause microfluidics enabled ap reconcentration of Ab 1-40 from the sample solutionsb ased on the capture of monoclonal antibody-modified magnetic particles. [57] Mass spectrometry (MS) has emerged as am ethod for detecting Ab in ar eliable way because of its accuracy and precision. [58] Recent progress in MS-based detection allowed for accurate measurements of Ab.…”