An electrochemical biosensor to identify the phenotype of aggressive breast cancer cells

Identifying the phenotype of aggressive breast cancer (BC) cells is vital for the effectiveness of surgical intervention and standard-of-care therapy. HER-2 is overexpressed in aggressive BC and MMP-2 is a crucial indicator of invasiveness and metastasis of BC, so we have proposed an electrochemical biosensor in this work to identify the phenotype of aggressive BC cells via detection of HER-2 together with MMP-2 by designing a dual-trapping peptide and a metal organic framework (MOF)-based probe. Specifically, the designed peptide contains both a HER-2 recognition sequence and MMP-2-specific substrate, while the MOF-based probe (AuNPs@HRP@ZIF-8), prepared by loading horseradish peroxidase (HRP) and gold nanoparticles (AuNPs) on ZIF-8, can also combine with the peptide. Consequently, sensitive and specific detection of both HER-2 and MMP-2 can be achieved in the wide range from 50 fg mL^-1 to 50 ng mL^-1 and 10 fg mL^-1 to 10 ng mL^-1, respectively, and the biosensor can distinguish HER-2⁺ BC cells and evaluate the invasion capability, which might be extended to provide a method for the accurate identification of tumor features in BC subtypes.