Label‐Free Detection and Translocation Dynamics Study of Single‐Molecule Herceptin Using Solid‐State Nanopores

Abstract Herceptin (or trastuzumab) is an important therapeutic monoclonal antibody (mAb) used in the treatment of HER2‐positive breast cancer. Real‐time counting and characterization of Herceptin is a fundamental step in the field of disease‐related diagnosis and therapy. Solid‐state nanopore‐based biosensors have been proved to hold great potential in characterizing the properties of proteins at the single‐molecule level for in vitro diagnosis. Here, the label‐free detection and detailed translocation dynamics study of Herceptin using solid‐state nanopores are demonstrated. By constricting nanopore size close to the size of Herceptin, the detection sensitivity and temporal resolution have been significantly improved, allowing the delicate probing of the structural information of single‐molecule Herceptin. Therefore, three types of Herceptin translocation events are identified through nanopores, single‐level, multi‐level and spike‐like events, emerged at different voltages regimes, indicating the unfolding kinetics of Herceptin under electric field. The potential influence of a high electric field on complex biomolecules is highlighted and a novel prospective platform is provided for label‐free detection of single‐molecule therapeutic monoclonal antibodies via solid‐state nanopores as a miniaturized biomedical device.