Early diagnosis of Parkinson's disease using split aptamer-based lateral flow assay with saliva sample.

Parkinson's disease (PD), the second most common neurodegenerative disorder, is typically diagnosed based on clinical observation of motor symptoms such as resting tremor, rigidity, and bradykinesia. This underscores the urgent need for a diagnostic tool capable of detecting PD at an earlier stage. Since the appearance of α-synuclein oligomer in saliva occurs earlier than the onset of motor symptoms, we introduce a lateral flow strip utilizing split aptamer to detect α-synuclein oligomer in the saliva of PD patients. When α-synuclein oligomer are present, they facilitate the reassembly of split aptamer, creating an "aptamer-α-synuclein oligomer-aptamer" sandwich structure. This assembly allows DNA-modified gold nanoparticles to be captured on the test line of the strip, producing a visible red band. Through careful optimization of the strip's operational conditions, this system exhibited a linear relationship within the range 0-10 µmol/L and a LOD of 62.72 nmol/L. Quantitative analysis of the results from PD patients showed positive outcomes in 14 out of 20 cases. Compared to existing detection methods, this approach offers several advantages, including visual results, short detection time, ease of use, low cost, portability and no requirement for complex sample pretreatment. These features make it a promising tool for the early diagnosis and visual assessment of PD.