High enhancement of sensitivity and reproducibility in label-free SARS-CoV-2 detection with graphene field-effect transistor sensors through precise surface biofunctionalization control Lozano Chamizo, Laura Márquez González, Carlos Marciello, Marzia Galdón Gil, José Carlos de la Fuente Zapico, Elsa Martínez Mazón, Paula González Rumayor, Víctor Filice, Marco Gámiz Pérez, Francisco Jesús Graphene field effect transistor Biosensor Oriented immobilization The COVID-19 pandemic has taught us valuable lessons, especially the urgent need for a widespread, rapid and sensitive diagnostic tool. To this, the integration of bidimensional nanomaterials, particularly graphene, into point-of-care biomedical devices is a groundbreaking strategy able to potentially revolutionize the diagnostic landscape. Despite advancements in the fabrication of these biosensors, the relationship between their surface biofunctionalization and sensing performance remains unclear. Here, we demonstrate that the combination of careful sensor fabrication and its precise surface biofunctionalization is crucial for exalting the sensing performances of 2D biosensors. Specifically, we have biofunctionalized Graphene Field-Effect Transistor (GFET) sensors surface through different biochemical reactions to promote either random/heterogeneous or oriented/homogeneous immobilization of the Anti-SARS-CoV-2 spike protein antibody. Each strategy was thoroughly characterized by in-silico simulations, physicochemical and biochemical techniques and electrical characterization. Subsequently, both biosensors were tested in the label-free direct titration of SARS-CoV-2 virus in simulated clinical samples, avoiding sample preprocessing and within short timeframes. Remarkably, the oriented GFET biosensor exhibited significantly enhanced reproducibility and responsiveness, surpassing the detection sensitivity of conventional non-oriented GFET by more than twofold. This breakthrough not only involves direct implications for COVID-19 surveillance and next pandemic preparedness but also clarify an unexplored mechanistic dimension of biosensor research utilizing 2D-nanomaterials. 2024-06-13T07:32:23Z 2024-06-13T07:32:23Z 2024-01-20 journal article Lozano-Chamizo, Laura, et al. High enhancement of sensitivity and reproducibility in label-free SARS-CoV-2 detection with graphene field-effect transistor sensors through precise surface biofunctionalization control. Biosensors and Bioelectronics 250 (2024) 116040 [10.1016/j.bios.2024.116040] https://hdl.handle.net/10481/92552 10.1016/j.bios.2024.116040 eng info:eu-repo/grantAgreement/EC/NextGenerationEU/CPP2022-009952 http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional Elsevier