Optical Sensing Platforms for Detecting Alzheimer's Disease Blood Biomarkers: From Laboratory Assays to Clinical Validation

ABSTRACT Blood sampling is minimally invasive, readily accessible, and capable of allowing for precise detection of Alzheimer's Disease (AD)‐related biomarkers, highlighting the significance of blood biomarker discovery for early diagnosis and intervention, as well as for treatment monitoring and prognosis assessment in AD patients. Up to now, a variety of optical sensing platforms, such as fluorescence, surface plasmon resonance (SPR), surface‐enhanced Raman scattering (SERS), optical fibers, and electrochemical methods, have all shown high performance for the detection of AD‐related biomarkers in blood. This review focuses on the recent progress in the aspect of optical sensing methods in the past five years, including fluorescence, SERS, SPR, and colorimetric methods, for the detection of AD biomarkers in blood like Aβ, tau, miRNA, and apolipoprotein E4 (APOE4). In addition, the current challenges related to detecting trace‐level AD biomarkers in blood, and the emerging diagnostic strategies for AD are discussed.