Direct and selective nanosensor for amyloid-β oligomers in serum for Alzheimer's disease diagnosis.

The rising prevalence of Alzheimer's disease (AD) highlights an urgent need for ultra-sensitive diagnostic tools that facilitate early detection and intervention. Soluble Aβ oligomers (AβOs) have emerged as a key focus due to their specificity for AD pathology. This study introduces a magnetic nanoplatform-based ultrasensitive diagnostic assay for AβO detection, utilizing a novel custom-designed AβO-selective fluorophore, named O-SLM. This innovative approach achieves a sensitivity nearly tenfold greater than that of a comparative ELISA kit, with a detection limit as low as 25 fM. The assay requires minimal sample volumes and streamlines the protocol by omitting detection antibodies. It effectively distinguishes AD patients from healthy individuals through serum AβO quantification, demonstrating the versatility of our ultra-sensitive assay across various biomarkers.