Concurrent Detection of Amyloid-β Biomarkers via Dual-Channel Graphene Field-Effect Transistor with Liquid-Metal Van Der Waals Contacts for Alzheimer Screening.

Early and accurate detection of Alzheimer's disease (AD) is demanding for timely interventions to slow disease progression. Graphene field-effect transistors (GFETs) are promising in AD biosensors due to their surface sensitivity, nonlabeling, and quick signal detection. Here, we developed a dual-channel GFET integrated with Galinstan liquid-metal electrodes. These electrodes establish van der Waals contacts with graphene, simplifying the manufacturing process by eliminating the need for high temperatures or significant energy inputs. This liquid metal electrodes reduce channel damage and significantly boost charge carrier mobility, with electron mobility reaching 5320 cm2·V-1·s-1 and hole mobility at 5572 cm2·V-1·s-1, surpassing traditional gold electrodes. The enhanced electrical performance of the Liquid metal GFET (LM-GFET) facilitates the highly sensitive and specific detection of Alzheimer's disease (AD) biomarkers. Its dual-channel configuration allows for the simultaneous detection of amyloid-β (Aβ) peptides Aβ40 and Aβ42, and the calculation of the Aβ42/Aβ40 ratio, providing a reliable marker for early stage AD diagnosis. The demonstrated robustness, stability, and improved performance position the LM-GFET as an effective tool for noninvasive AD diagnostics, underscoring its potential in advancing graphene-based biosensors for clinical use.