Optical fiber apta-biosensor for Alzheimer’s disease via amyloid-β oligomers sensing based on polished microsphere-LSPR

Alzheimer's disease (AD) presents an increasing global health challenge, highlighting the need for early and accessible diagnostic methods. This study introduces a highly sensitive optical fiber apta-biosensor based on localized surface plasmon resonance (LSPR) for the early detection of Amyloid beta (1-42) (Aβ₄₂), a crucial biomarker for AD. The RI sensitivity of the sensor was obtained at 716.53 nm/RIU which can be used as a good candidate for label-free biosensing. Upon Aβ₄₂ binding, a distinct blue shift was observed, with a detection limit of 0.01 fM and a detection range from 50 fM to 5 μM. The sensor’s high sensitivity, real-time monitoring, and label-free operation highlight its potential as a cost-effective alternative for early AD diagnosis, paving the way for widespread clinical applications.