A smart nanosensor for the detection of human immunodeficiency virus and associated cardiovascular and arthritis diseases using functionalized graphene-based transistors

Human immunodeficiency virus (HIV), which isa worldwide public health issue, is commonly associated with cardiovascular disorders (CVDs) and rheumatoid arthritis (RA). A smart nanosensor was developed for the detection of HIV and its related diseases (CVDs and RA) using graphene-based field-effect transistors (FETs). In this study, amine-functionalized graphene (afG) was conjugated with antibodies [anti-p24 for HIV, anti-cardiac troponin 1 (anti-cTn1) for CVDs, and anti-cyclic citrullinated peptide (anti-CCP) for RA] to detect various biomarkers. The antibodies were covalently conjugated to afG via carbodiimide activation. The bioconjugate (graphene-antibody) was characterized by various biophysical techniques such as UV-Vis, Raman spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The electrochemical performance of the sensor was evaluated with respect to changes in the resistance of the electrode surface due to the interaction of the antigen with its specific antibody. The developed sensor was highly sensitive and showed a linear response to p24, cTn1, and, CCP from 1 fg/mL to 1 mu g/mL. The limit of detection (LOD) was 100 fg/mL for p24 and 10 fg/mL for cTn1 and CCP under standard optimized conditions. The graphene-based smart nanodevice demonstrated excellent performance; thus, it could be used for the on-site detection of HIV, CVD, and RA biomarkers in real samples.