Attomolar detection of hepatitis C virus core protein powered by molecular antenna-like effect in a graphene field-effect aptasensor

Biosensors based on graphene field-effect transistors have become a promising tool for detecting a broad range of analytes. However, their performance is substantially affected by the functionalization protocol. In this work, we use a controlled in-vacuum physical method for the covalent functionalization of graphene to construct ultrasensitive aptamer-based biosensors (aptasensors) able to detect hepatitis C virus core protein. These devices are highly specific and robust, achieving attomolar detection of the viral protein in human blood plasma. Such an improved sensitivity is rationalized by theoretical calculations showing that induced polarization at the graphene interface, caused by the proximity of covalently bound molecular probe, modulates the charge balance at the graphene/aptamer interface. This charge balance causes a net shift of the Dirac cone providing enhanced sensitivity for the attomolar detection of the target proteins. Such an unexpected effect paves the way for using this kind of graphene-based functionalized platforms for ultrasensitive and real-time diagnostics of different diseases.EU Graphene Flagship funding (Grant Graphene Core3 881603), the Ministerio de Ciencia e Innovación of Spain: PID2020-113142RB-C21, the European Structural Funds via FotoArt-CM project (P2018/NMT-4367) and the Portuguese Foundation for Science and Technology (FCT) via the Strategic Funding UIDB/04650/2020. Work at CAB was funded by the Spanish Ministerio de Ciencia e Innovación (MICINN) grant no. PID2019-104903RB-I00 and the Spanish Agencia Estatal de Investigación (AEI) Project no. MDM-2017-0737 - Unidad de Excelencia “María de Maeztu,” and it also benefits from the interdisciplinary framework provided by CSIC through “LifeHUB.CSIC” initiative (PIE 202120E047-CONEXIONES-LIFE). CIBERehd is funded by Instituto de Salud Carlos III (ISCIII). A.N. is supported by the predoctoral fellowship PRE-CAB-BIOMOLECULAS 2 from INTA. B.T-V. is supported by the predoctoral fellowship TS17/16 from INTA and by the CSIC “Garantía Juvenil” contract CAM19_PRE_CAB_001 funded by Comunidad de Madrid (CAM). FCT supports T.D. and P.C. under Ph.D. grants SFRH/BD/08181/2020 and SFRH/BD/128579/2017. M.M. would like to thank Comunidad de Madrid for the predoctoral grant IND2020/BIO-17523. P.A. and C.B. also acknowledge the support provided by La Caixa Foundation through Project LCF/PR/HR21/52410023. L. V. would like to thank Comunidad de Madrid (TRANSNANOAVANSENS program: S2018-NMT-4349) and E.V. García-Frutos for her assistance during the AFM experiments

Attomolar detection of hepatitis C virus core protein powered by molecular antenna-like effect in a graphene field-effect aptasensor

This study presents the development of a lab-on-a-chip (LoC) by integrating a graphene field-effect transistor (FET) chip with a programmable microfluidic device for DNA detection. The real-time biochemical events on the graphene FET chip were monitored through Dirac voltage shift data from the portable graphene curve reader with changes dependent on the fluidic flow into the sensing interface by a fully automated programmable microfluidic system. High sensitivity with high reliability can be obtained with a nine-graphene sensor layout on a single chip. The portable graphene curve reader also provides a tunable electrical parameter setup and straightforward data acquisition. Fluidic control was performed through a multi-position valve, allowing sequential commands for liquid injection into the polydimethylsiloxane (PDMS) flow cell mounted on the sensing chip. The flow cell design with impinging jet geometry and the microfluidic system packaging offer high precision and portability as a less laborious and low-cost sensing setup. The merged system allows for various functionalities, including probe DNA (pDNA) immobilization, a blocking step, and DNA hybridization with stable signal output autonomously, even in a long-run experimental setup. As a DNA sensor, the proposed prototype has demonstrated a high sensitivity of ~44 mV/decade of target DNA concentration, with an outstanding limit of detection (LoD) of ~0.642 aM, making it one of the most sensitive sensors reported up to date. The programmable device has demonstrated essential versatilities for biomolecular detection in a fully portable and automated platform.This research is supported by PORTGRAPHE-Control of Port and Douro Wines authenticity using graphene DNA sensors project co-funded by Fundação para a Ciência e a Tecnologia (FCT) Portugal (PTDC/BIA-MOL/31069/2017) and the ERDF through COMPETE2020 (POCI-01–0145-FEDER-031069). One of the authors (Telma Domingues) acknowledges a Ph.D. grant from Fundação para a Ciência e a Tecnologia (FCT) Portugal (SFRH/BD/08181/2020). FCT partially supported University of Minho´s research in the Strategic Funding UIDB/04650/2020

Biocapteur de détection du virus de l'hépatite C

[EN] The present invention relates to an electrolyte-gated graphene field-effect transistor (G-FET) based biosensor characterized in that it comprises an aptamer against core protein of hepatitis C virus (HCV), particularly the aptamer comprising the nucleotide sequence SEQ ID NO:1, which allows the detection of core protein of HCV in the attomolar range both in buffer and in human plasma, greatly improving the sensitivity and specificity of the detection of HCV in biological samples.[FR] La présente invention concerne un biocapteur de transistor à effet de champ de graphène (G-FET) à grille électrolytique caractérisé en ce qu'il comprend un aptamère contre une protéine nucléaire du virus de l'hépatite C (VHC), en particulier l'aptamère comprenant la séquence nucléotidique SEQ ID NO : 1, ce qui permet la détection de la protéine nucléaire du VHC dans la plage attomolaire à la fois dans le tampon et dans le plasma humain, ce qui améliore considérablement la sensibilité et la spécificité de la détection du VHC dans des échantillons biologiques.Peer reviewedConsejo Superior de Investigaciones Científicas, Instituto Nacional de Técnica Aeroespacial, International Iberian Nanotechnology Laboratory, Universidade do MinhoA1 Solicitud de patente con informe sobre el estado de la técnic

Biocapteur en graphène pour la détection du virus de l'hépatite C

The present invention relates to an electrolyte-gated graphene field-effect transistor (G-FET) based biosensor characterized in that it comprises an aptamer against core protein of hepatitis C virus (HCV), particularly the aptamer comprising the nucleotide sequence SEQ ID NO:1, which allows the detection of core protein of HCV in the attomolar range both in buffer and in human plasma, greatly improving the sensitivity and specificity of the detection of HCV in biological samples.Peer reviewedConsejo Superior de Investigaciones Científicas, Instituto Nacional de Técnica Aeroespacial, International Iberian Nanotechnology Laboratory, Universidade do MinhoA1 Solicitud de patente con informe sobre el estado de la técnic