Single‐Step Functionalization Strategy of Graphene Microtransistor Array with Chemically Modified Aptamers for Biosensing Applications

Abstract

Graphene solution‐gated field‐effect transistors (gSGFETs) offer high potential for chemical and biochemical sensing applications. Among the current trends to improve this technology, the functionalization processes are gaining relevance for its crucial impact on biosensing performance. Previous efforts are focused on simplifying the attachment procedure from standard multi‐step to single‐step strategies, but they still suffer from overreaction, and impurity issues and are limited to a particular ligand. Herein, a novel strategy for single‐step immobilization of chemically modified aptamers with fluorenylmethyl and acridine moieties, based on a straightforward synthetic route to overcome the aforementioned limitations is presented. This approach is benchmarked versus a standard multi‐step strategy using thrombin as detection model. In order to assess the reliability of the functionalization strategies 48‐gSGFETs arrays are employed to acquire large datasets with multiple replicas. Graphene surface characterization demonstrates robust and higher efficiency in the chemical coupling of the aptamers with the single‐step strategy, while the electrical response evaluation validates the sensing capability, allowing to implement different alternatives for data analysis and reduce the sensing variability. In this work, a new tool capable of overcome the functionalization challenges of graphene surfaces is provided, paving the way toward the standardization of gSGFETs for biosensing purposes.

Ethanol Solvation of Polymer Residues in Graphene Solution-Gated Field Effect Transistors

“…In the domain of field effect transistors (FETs), these residues play a crucial role, affecting the modulation of electrical current in the graphene channel and the variability in the current-to-voltage curves. In the context of solution-gated field-effect transistors (SGFETs), this lack of homogeneity negatively alters the calibration of these systems, a crucial requirement for sensing and biosensing applications. − Specifically, in such applications utilizing graphene-based SGFETs (gSGFET), monitoring changes in charges on the channel during functionalization or detection becomes critical. This emphasizes the importance of controlling contaminants or residues on graphene surfaces.…”