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Article

AuNP/Magnetic Bead-Enhanced Electrochemical Sensor Toward Dual Saliva Alzheimer’s Biomarkers Detection

1
School of Stomatology, Dalian Medical University, Dalian 116000, China
2
State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
3
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
4
School of Science and Technology, Shanghai Open University, Shanghai 200433, China
5
Lin Gang Laboratory, Shanghai 201306, China
6
Shanghai Frontier Innovation Research Institute, Shanghai, 201108, China
*
Authors to whom correspondence should be addressed.
These authors contributed equally to this work.
Sensors 2025, 25(13), 4088; https://doi.org/10.3390/s25134088
Submission received: 30 April 2025 / Revised: 27 June 2025 / Accepted: 27 June 2025 / Published: 30 June 2025
(This article belongs to the Section Biomedical Sensors)

Abstract

Alzheimer’s disease (AD) early screening requires non-invasive, high-sensitivity detection of low-abundance biomarkers in complex biofluids like saliva. In this study, we present a miniaturized, silicon-based electrochemical sensor for sequential detection of two AD salivary biomarkers, lactoferrin (Lf) and amyloid β-protein 1-42 (Aβ1-42), on a single reusable electrode. The sensor features a three-electrode system fabricated by sputter-coating a quartz substrate with gold (Au) sensing electrodes, which are further modified with gold nanoparticles (AuNPs) to form 3D dendritic structures that enhance surface area and electron transfer. To improve specificity, immunomagnetic beads (MBs) are employed to selectively capture and isolate target biomarkers from saliva samples. These MB–biomarker complexes are introduced into a polydimethylsiloxane chamber aligned with Au sensing electrodes, where a detachable magnet localizes the complexes onto the electrode surface to amplify redox signals. The AuNPs/MBs sensor achieves detection limits of 2 μg/mL for Lf and 0.1 pg/mL for Aβ1-42, outperforming commercial ELISA kits (37.5 pg/mL for Aβ1-42) and covering physiological salivary concentrations. After the MBs capture the biomarkers, the sensor can output the result within one minute. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements confirm enhanced electron transfer kinetics on AuNP-decorated surfaces, while linear correlations (R2 > 0.95) validate quantitative accuracy across biomarker ranges. The compact and integrated design eliminates reliance on bulky instrumentation and enables user-friendly operation, establishing a promising platform for portable, cost-effective AD screening and monitoring.
Keywords: electrochemical sensor; Alzheimer’s disease; immunomagnetic beads; gold nanoparticles electrochemical sensor; Alzheimer’s disease; immunomagnetic beads; gold nanoparticles

Share and Cite

MDPI and ACS Style

Zhao, P.; Wang, J.; Mao, H.; Zhou, L.; Wu, Z.; Lu, Y.; Sun, T.; Hui, J.; Ma, G. AuNP/Magnetic Bead-Enhanced Electrochemical Sensor Toward Dual Saliva Alzheimer’s Biomarkers Detection. Sensors 2025, 25, 4088. https://doi.org/10.3390/s25134088

AMA Style

Zhao P, Wang J, Mao H, Zhou L, Wu Z, Lu Y, Sun T, Hui J, Ma G. AuNP/Magnetic Bead-Enhanced Electrochemical Sensor Toward Dual Saliva Alzheimer’s Biomarkers Detection. Sensors. 2025; 25(13):4088. https://doi.org/10.3390/s25134088

Chicago/Turabian Style

Zhao, Pengcheng, Jieyu Wang, Hongju Mao, Lin Zhou, Zhenhua Wu, Yunxing Lu, Teng Sun, Jianan Hui, and Guowu Ma. 2025. "AuNP/Magnetic Bead-Enhanced Electrochemical Sensor Toward Dual Saliva Alzheimer’s Biomarkers Detection" Sensors 25, no. 13: 4088. https://doi.org/10.3390/s25134088

APA Style

Zhao, P., Wang, J., Mao, H., Zhou, L., Wu, Z., Lu, Y., Sun, T., Hui, J., & Ma, G. (2025). AuNP/Magnetic Bead-Enhanced Electrochemical Sensor Toward Dual Saliva Alzheimer’s Biomarkers Detection. Sensors, 25(13), 4088. https://doi.org/10.3390/s25134088

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