A recent approach in disease diagnosis and viral epidemics is aimed atpoint-of-care tests that could be administered near the patient rather thantime-consuming processes involving centralized laboratories. Point-of-caredevices provide rapid results in simple and low-cost manner requiring onlysmall sample volumes. These devices will strongly benefit from advancedmaterials and fabrication methods to improve their efficiency andsensitivity. We report a functionalized carbon nanotube label for animmunosensor application. Carbon nanotube label was prepared by modifyingthe carbon nanotube surface to anchor biomolecules. First, the carboxylicacid treated multi-walled carbon nanotubes (MWCNTs) were uniformly dispersedwith polyvinylpyrrolidone (PVP) by sonication in aqueous solution. PVPpartially wraps around the carbon nanotubes and exposes the surface of thenanotubes for further functionalization. The MWCNTs were then conjugatedwith human immunoglobulin G (IgG) using EDC/Sulfo-NHS coupling chemistry,where the antibodies occupied sites not covered by PVP. The dispersion,surfactant modification, and antibody conjugation of the MWCNTs were alsoconfirmed using SEM and TEM images. The successful functionalization of theMWCNTs and reactivity of the covalent attached antibodies were demonstratedfor specific antigen binding on the microelectrode device. The carbonnanotube-based detection mechanism could be tailored for screening variousanalyte specific molecules. Furthermore, the reported technique could easilybe integrated in various microfluidic and lab-on-a-chip devices for thedevelopment of functional electronic sensors providing quantitative,sensitive, and low-cost detection in pointof- care setup.