Abstract
Neurodegenerative diseases involve the progressive loss of neurons in the brain and nervous system, leading to functional decline. Early detection is critical for improving outcomes and advancing therapies. Optical biosensors, some of which offer rapid, label-free, and ultra-sensitive detection, have been applied to early diagnosis and drug screening. This review examines the principles and performance of different optical biosensors used for diagnosing neurodegenerative diseases and discusses potential future advancements.