Highly sensitive surface-enhanced Raman scattering (SERS) imaging for phenotypic diagnosis and therapeutic evaluation of breast cancer

The invasion and metastasis of breast cancer are closely related to various biomarkers expressed on the surface of tumor cells and the tumor microenvironment. The deficiency of sensitive phenotypic diagnosis and therapeutic evaluation toward breast cancers represents a significant challenge in cancer diagnosis and therapy. Herein, we report a crucial example of surface-enhanced Raman scattering (SERS)-based imaging utilizing highly sensitive SERS probes to serve as a robust platform for the detection of breast cancer phenotypic biomarkers expressed on the cell surfaces and therapeutic evaluation after chemical therapy and surgery. The SERS probes feature gold-silver (Au@Ag) core–shell nanoparticles with double-layer Raman reporters embedding on the surfaces of the gold core and silver shell, respectively, which further conjugate with specific antibodies. The highly enhanced SERS signals permit the sensitive detection of specific phenotypic biomarkers expressed on the cell surface. In the present work, the epidermal growth factor receptors (EGFR and ErbB2) and insulin-like growth factor 1 (IGF1) were selected as the target biomarkers and assessed the expression in MCF-10A human normal breast cell line and MDA-MB-468, SK-BR-3, KPL-4 human breast cancer cell lines through the SERS-based imaging technique. In the xenotransplanted breast tumor model, systematic delivery of SERS probes enabled precise therapeutic evaluation after anticancer drug tamoxifen therapy and surgery treatment through SERS imaging. Consequently, SERS imaging was consistent with H&E and Masson staining. These results suggest the proposed SERS-based imaging technique has a strong potential to be a powerful tool for precise diagnosis and therapeutic efficacy of breast cancers.