ERBB2 and breast cancer: further advanced the technology by integrating AuSt nanoparticle‐based SERS platform with a paper‐based vertical flow design for simultaneous quantification of three exosomal proteins (MUC1, HER2, and CEA) in breast cancer.[225] As shown in Figure 5b, the test pad features four distinct wax‐printed spots, each containing different capture aptamers for MUC1, HER2, CEA, and a CD63 control.