Researchers have developed a biosensor that uses a single polyaniline (PANI) nanowire to detect the cardiac biomarker myoglobin (Myo) and immunoglobulin G (IgG). The single PANI nanowires were grown using an electrochemical method between a pair of patterned electrodes. The nanowires were then functionalized with monoclonal antibodies (mAbs) specific to Myo or IgG using 1-ethyl-3-(3-dimethyaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimde (NHS) to form strong covalent bonds between the mAbs and the PANI nanowires. The researchers verified the functionalization using Raman spectroscopy and fluorescence microscopy. By measuring the conductance change of the functionalized single PANI nanowires, the researchers were able to detect the target proteins of IgG and Myo. The biosensor demonstrated excellent specificity towards the expected target detection, with no response observed when exposed to a non-specific protein. The detection limit was found to be 3 ng/mL for IgG and 1.4 ng/mL for Myo, and the biosensor exhibited a fast response time of a few seconds. The single PANI nanowire-based biosensor is a promising technology for the detection of cardiac markers and other proteins, owing to its high sensitivity, good specificity, and fast response time. The surface immobilization technique employed in this research could also be applied to the detection of other mAbs for various protein detection tests, including cancer markers and other cardiac markers. Overall, this study demonstrates the potential of PANI nanowires as a highly sensitive and specific biosensor platform for protein detection.