Polymeric Complements to the Alzheimer's Disease Biomarker β-Amyloid Isoforms Aβ1–40 and Aβ1–42 for Blood Serum Analysis under Denaturing Conditions

Abstract

Treatment of Alzheimer's disease (AD) is plagued by a lack of practical and reliable methods allowing early diagnosis of the disease. We here demonstrate that robust receptors prepared by molecular imprinting successfully address current limitations of biologically derived receptors in displaying affinity for hydrophobic peptide biomarkers for AD under denaturing conditions. C-terminal epitope-imprinted polymers showing enhanced binding affinity for Aβ1-42 were first identified from a 96-polymer combinatorial library. This information was then used to synthesize molecularly imprinted polymers for both of the β-amyloid (Aβ) isoforms and a corresponding nonimprinted polymer. A solid-phase extraction method was developed to be compatible with sample loading under conditions of complete protein denaturation. This resulted in a method capable of quantitatively and selectively enriching a shorter C-terminal peptide corresponding to the sequences Aβ33-40 and Aβ33-42 as well as the full-length sequence Aβ1-40 and Aβ1-42 from a 4 M guanidinum chloride solution. Application of the method to serum allowed selective, high-recovery extraction of both biomarkers at spiking levels marginally higher than clinically relevant concentrations found in cerebrospinal fluid.

Molecular imprinting for removing highly toxic organic pollutants

“…Because MIPs contain ''tailor-made'' binding sites, they have high selectivity and affinity for the template. The molecular recognition ability of MIPs allows these materials to be used in various fields such as chemical analysis and detection, 6,7 separation and purification, 8 drug delivery, 9 and catalysis. 10 …”

Epitope Imprinting Approach to Monitor Diseases

“…In a review on diagnostic strategies of Alzheimer's disease, authors concluded that epitope imprinting of key proteins are the most promising strategy for this disease. Diagnosis of Alzheimer's disease via imprinting was attempted by detecting the β amyloid peptides [32]. C-terminal epitope-imprinted polymers for Aβ142 were first identified through combinatorial library, and then it was used to synthesize MIPs for the β-amyloid isoforms under denaturing condition.…”

Protein-imprinted materials: rational design, application and challenges

“…These epitope imprinting approaches are applicable even in organic solvents used for traditional small-molecule imprinting, because small peptides are not subject to the major conformational and degradation problems which occur in whole-protein imprinting [33][34][35][36].…”