The robust electrochemical detection of a Parkinson's disease marker in whole blood sera

Abstract

Protein aggregation, leading to amyloid deposition in the brain, is implicated in the pathology of a number of increasingly prevalent neurodegeneration states such as Parkinson's disease (PD), Alzheimer's disease and prion diseases. The body's protective response to the formation of such deposits is to generate specific autoimmune antibodies. Alpha-synuclein, a natively unfolded protein relatively abundant in the brain, is the main constituent of Lewy body amyloid dispositions in PD. Previous assays determining content of alpha-synuclein in bodily fluids have proven to be largely inconclusive. Here we have taken a novel approach in utilising alpha-synuclein modified electrodes to sample the autoantibodies generated as the body responds to changes in its homeostasis. We show that these electroanalytical assays not only robustly distinguish between disease state and control individuals but also map out disease progression with unprecedented sensitivity and clarity. The impedimetric electrode surfaces are highly specific, reusable, exhibit a linear range from 0.5 to 10 nM and a detection limit of 55 ± 3 pM. We believe electroanalyses such as these, possible with less than 10 microlitres of fluid and a total assay time of only a few minutes, to be of value for early diagnosis of PD and possibly other alpha-synucleinopathies, and for monitoring disease progression and effects of possible disease modifying interventions.