Exploring the Relationship Between Alpha-synuclein Concentration and Parkinson's Disease Progression with Graphene Aptasensors*

Parkinson’s disease is a neurodegenerative disorder with no standard method of diagnosis. Studies have shown that the concentration of α-synuclein (α-syn) in the cerebral spinal fluid (CSF) is lower in Parkinson’s patients than in healthy patients, making this protein a viable biomarker for disease progression. Aptamers, or nucleic acid oligomers selected to bind a specific molecular target, can be used in conjunction with graphene field effect transistor (GFET) arrays to create biosensors capable of detecting a variety of targets. Here, we have utilized aptamer-functionalized GFET sensor arrays to detect the presence of α-syn. We show that our functionalized GFET arrays have a α-syn detection limit of 1 nM in deionized water. GFET arrays were fabricated using traditional photolithography with graphene grown via chemical vapor deposition. Functionalization of the GFET array was characterized structurally using atomic force microscopy and electronically through measurements of the current- gate voltage characteristics. In the future, we will move towards detecting α-synuclein in more complex solutions, leading to the detection of α-syn in cerebral spinal fluid samples from patients with varying levels of Parkinson’s progression.