Biosensors for Alzheimer's Disease Detection and Monitoring: Bridging Preclinical and Clinical Applications

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder, characterized by profound cognitive impairment and irreversible memory loss. Early and reliable diagnosis is essential but remains challenging due to the limitations of current clinical tools. Conventional methods are invasive, expensive, and impractical for routine or large‐scale screening. Recent advances in biosensor technology have enabled rapid, sensitive, and low‐cost detection of clinically relevant AD biomarkers, like Aβ40/42, Aβ oligomers, total tau, and phosphorylated tau isoforms. This review highlights major developments in electrochemical biosensors, including immunosensors that utilize oriented antibody immobilization, aptasensors capable of highly specific target recognition, and hybrid systems that integrate both modalities. The incorporation of nanomaterials, such as gold nanostructures, graphene derivatives, carbon dots, zinc oxide, and core–shell SiO 2 @Ag nanoparticles, has significantly enhanced electron transfer, biomolecule loading, and signal amplification, enabling detection limits down to the femtomolar range. Microfluidic and dielectrophoretic enrichment platforms further improve performance by enhancing analyte capture and reducing interference from complex biological matrices. Despite these advances, challenges remain in addressing matrix effects, standardizing analytical formats, enabling multiplex detection, and achieving clinical validation. Future progress in sensor integration, point‐of‐care design, and data analytics is expected to accelerate translation toward early AD diagnosis and continuous monitoring.