ERBB2 and breast carcinoma: The sensitivitywas obtained by tracking the most sensitive mode of the spectrum.The surface of the TFBG–ball resonator served as a platformfor immobilizing the sHER2-specific antibody Trastuzumab and evaluatingits performance for the detection of the breast cancer biomarker HER2.The immobilization of the antibody was achieved by silane couplingsurface chemistry.