MMP14 and breast carcinoma: Core–shell PMNPs that incorporate Raman reporters—such as silver core–silica shell NPs with 4-mercaptobenzonitrile in the interfacial layer—enable interference-free SERS detection of membrane type-1 matrix metalloproteinase (MT1-MMP) in breast cancer cells, overcoming spectral overlap and enhancing specificity for clinical diagnostics [51].