Hydrogel-Coated Gate Field-Effect Transistor for Real-Time and Label-Free Monitoring of β-Amyloid Aggregation and Its Inhibition

In this paper, we propose a hydrogel-coated gate field-effect transistor (FET) for the real-time and label-free monitoring of beta-amyloid (A beta) aggregation and its inhibition. The hydrogel used in this study is composed of poly tetramethoxysilane (TMOS), in which A beta monomers are entrapped and then aggregate, and coated on the gate insulator; that is, A beta aggregation is induced in the vicinity of the sensing surface. With the A beta hydrogel-coated gate FET, the steplike decrease in the surface potential of the A beta hydrogel-coated gate electrode is electrically monitored in real time, according to the stepwise aggregation of A beta monomers to form into fibrils through oligomers and so forth in stages. This is because the capacitance of the A beta-hydrogel membrane decreases depending on the stage of aggregation; that is, the hydrophobicity of the A beta-hydrogel membrane increases stepwise depending on the amount of A beta aggregates. The formation of A beta fibrils is also confirmed in the measurement solution using a fluorescent dye, thioflavin T, which selectively binds to the A beta fibrils. Moreover, the addition of daunomycin, an inhibitor of A beta aggregation, to the measurement solution suppresses the stepwise electrical response of the A beta hydrogel-coated gate FET. Thus, a platform based on the A beta hydrogel-coated gate FET is suitable for a simple screening system for inhibitors of A beta aggregation, which may lead the identification of potential therapeutic agents for Alzheimer's disease.

Automated summary

This paper proposes a hydrogel-coated gate field-effect transistor (FET) for real-time monitoring and inhibition of beta-amyloid (A beta) aggregation. By monitoring the stepwise aggregation process of A beta monomers, the surface potential of the hydrogel-coated gate electrode can be electrically monitored. The addition of an A beta aggregation inhibitor suppresses the electrical response of the hydrogel-coated gate FET.