A Highly Sensitive WS₂ Quantum Dots Nanocoated Surface Plasmonic Resonance Based Side Polished Fiber Sensor for Detection of Parkinson's Disease

In this letter, we propose a highly sensitive evanescent field based side polished fiber (SPF) biosensor nano-coated with tungsten disulfide (WS₂) quantum dots (QDs) for the label-free detection of Parkinson's disease (PD). alpha-synuclein (α-syn) is identified as a key biomarker for early and rapid diagnosis of PD. The sensing mechanism relies on surface plasmon resonance (SPR) based interaction between the evanescent field in the anti-α-syn antibodies immobilized on the (WS₂) QDs and side polished fiber region. The proposed biosensor demonstrates a sensitivity of 85% with a limit of detection (LOD) around 0.517 fg/mL. A maximum SPR wavelength shift of 97.62nm was observed at anα-syn concentration of 10⁵fg/mL. Further, the proposed biosensor exhibits an excellent selectivity towardα-syn compared to potential interfering proteins such as Amyloid-beta (Aβ42) and bovine serum albumin (BSA). Thus, the proposed WS₂QDs nano-coated SPF biosensor is a promising platform for point-of-care (PoC) diagnostics and preclinical assessment of PD.