biostudies-literatureUnknown12(12)de Souza Freire LThe COVID-19 pandemic has emphasized the importance and urgent need for rapid and accurate diagnostic tests for detecting and screening this infection. Our proposal was to develop a biosensor based on an ELISA immunoassay for monitoring antibodies against SARS-CoV-2 in human serum samples. The nucleocapsid protein (N protein) from SARS-CoV-2 was employed as a specific receptor for the detection of SARS-CoV-2 nucleocapsid immunoglobulin G. N protein was immobilized on the surface of a screen-printed carbon electrode (SPCE) modified with carboxylated graphene (CG). The percentage of IgG-SARS-CoV-2 nucleocapsid present was quantified using a secondary antibody labeled with horseradish peroxidase (HRP) (anti-IgG-HRP) catalyzed using 3,3',5,5'-tetramethylbenzidine (TMB) mediator by chronoamperometry. A linear response was obtained in the range of 1:1000-1:200 <i>v/v</i> in phosphate buffer solution (PBS), and the detection limit calculated was 1:4947 <i>v</i>/<i>v</i>. The chronoamperometric method showed electrical signals directly proportional to antibody concentrations due to antigen-antibody (Ag-Ab) specific and stable binding reaction.Biosensors1161https://www.ebi.ac.uk/biostudies/studies/S-EPMC9775996biostudies-literatureAn Electrochemical Immunosensor Based on Carboxylated Graphene/SPCE for IgG-SARS-CoV-2 Nucleocapsid Determination.PMC9775996Ruzo CMde Souza Freire LSalgado BBLalwani JDBTalu SMatos RRomaguera-Barcelay YFonseca Filho HBrito WRLalwani PSales MGFCordeiro ITavares APMAstolfi-Filho SGandarilla AMDfalseAn Electrochemical Immunosensor Based on Carboxylated Graphene/SPCE for IgG-SARS-CoV-2 Nucleocapsid Determination.The COVID-19 pandemic has emphasized the importance and urgent need for rapid and accurate diagnostic tests for detecting and screening this infection. Our proposal was to develop a biosensor based on an ELISA immunoassay for monitoring antibodies against SARS-CoV-2 in human serum samples. The nucleocapsid protein (N protein) from SARS-CoV-2 was employed as a specific receptor for the detection of SARS-CoV-2 nucleocapsid immunoglobulin G. N protein was immobilized on the surface of a screen-printed carbon electrode (SPCE) modified with carboxylated graphene (CG). The percentage of IgG-SARS-CoV-2 nucleocapsid present was quantified using a secondary antibody labeled with horseradish peroxidase (HRP) (anti-IgG-HRP) catalyzed using 3,3',5,5'-tetramethylbenzidine (TMB) mediator by chronoamperometry. A linear response was obtained in the range of 1:1000-1:200 <i>v/v</i> in phosphate buffer solution (PBS), and the detection limit calculated was 1:4947 <i>v</i>/<i>v</i>. The chronoamperometric method showed electrical signals directly proportional to antibody concentrations due to antigen-antibody (Ag-Ab) specific and stable binding reaction.2022-01-01T00:00:00Z2022 Dec2025-04-18T16:00:46.46Z2025-04-07T02:55:35.482ZS-EPMC97759963655112810.3390/bios12121161