Label-free immunodetection of α-synuclein by using a microfluidics coplanar electrolyte-gated organic field-effect transistor

• DOI: 10.1016/j.bios.2020.112433
• Publication Date: 2020-07-24T15:56:25Z
• Authors: Simona Ricci; Stefano Casalini; Vitaliy Parkula; Meenu Selvaraj; Gulseren Deniz Sa...; Pierpaolo Greco; Fabio Biscarini; Marta Mas-Torrent
• Keywords: Transistors, Electronic; Alpha-synuclein; Biosensing chip; Electrolyte-gated organic field-effect transistors; Microfluidics; Electrolyte-gated organic field-effect transistors; Microfluidics; Biosensing Techniques; 01 natural sciences; 0104 chemical sciences; 3. Good health; Alpha-synuclein; Electrolytes; alpha-Synuclein; Biosensing chip

The aggregation of α-synuclein is a critical event in the pathogenesis of neurological diseases, such as Parkinson or Alzheimer. Here, we present a label-free sensor based on an Electrolyte-Gated Organic Field-Effect Transistor (EGOFET) integrated with microfluidics that allows for the detection of amounts of α-synuclein in the range from 0.25 pM to 25 nM. The lower limit of detection (LOD) measures the potential of our integrated device as a tool for prognostics and diagnostics. In our device, the gate electrode is the effective sensing element as it is functionalised with anti-(α-synuclein) antibodies using a dual strategy: i) an amino-terminated self-assembled monolayer activated by glutaraldehyde, and ii) the His-tagged recombinant protein G. In both approaches, comparable sensitivity values were achieved, featuring very low LOD values at the sub-pM level. The microfluidics engineering is central to achieve a controlled functionalisation of the gate electrode and avoid contamination or physisorption on the organic semiconductor. The demonstrated sensing architecture, being a disposable stand-alone chip, can be operated as a point-of-care test, but also it might represent a promising label-free tool to explore in-vitro protein aggregation that takes place during the progression of neurodegenerative illnesses.