Dec 2, 2024
11:15am - 11:30am
Sheraton, Second Floor, Back Bay C
Abdul Wadood Tadbier1,Gabriele Kaminski Schierle1,Stephan Hofmann1
University of Cambridge1
Neurodegeneration signifies a persistent decline in neuronal function, characterised by irreversible damage, with Alzheimer’s Disease (AD) and Parkinson’s Disease (PD) being the most prevalent. The absence of a non-invasive, cost-effective, and user-friendly diagnostic method impedes early detection efforts, delaying progress in treatment development. We explore the use of graphene as a bio-interfacing material in this field, focusing on graphene-based multi-electrode arrays [1] and graphene field-effect transistors [2]. While the use of graphene offers high sensitivity and high transconductance, selectivity, reproducibility and stability in bio-interfacing environments remain significant obstacles. We report a remote gate electrolyte-gated graphene field-effect transistors (EGFETs) design that isolates the sensing electrolyte from the operational electrolyte. This design enables the utilisation of a single EGFET with multiple remote gates, reducing the need for multiple fabrications of EGFET and enhancing overall system reproducibility. We achieved reduced hysteresis and enhanced stability by optimising the fabrication process, including graphene transfer, substrate selection, contact resistance minimisation, bottom gate dielectric enhancement, and EGFET operation modifications. We applied such EGFET design to Alpha-synuclein (aSyn) detection. The aggregation of this protein has been well-established, notably leading to the formation of Lewy bodies, a hallmark associated with neuronal death in PD. We employed nanobodies, smaller fragments of whole antibodies, bringing the target protein closer to the surface of the sensor and enabling detection in high ionic media such as saliva which is demonstrated as a viable sampling location of aSyn and a promising alternative to cerebrospinal fluid, which requires highly invasive measurement. Our results showed an enhancement for the graphene-based biosensors which would offer a potential solution for neurodegenerative disease diagnosis.<br/>[1] Lu et al, bioRxiv 2024.02.22.581570; doi: https://doi.org/10.1101/2024.02.22.581570 (submitted to Advanced Science)<br/>[2] Tye et al, arXiv:2206.13239 https://doi.org/10.48550/arXiv.2206.13239