Li et al. engineered a U11 peptide modified gold nanocluster platform carrying the cathepsin E (CTSE)-sensitive PDT prodrug/imaging agent CRQAGFSL-5-aminolevulinic acid (5-ALA)/-cyanine 5.5 (Cy5.5) (AuS-U11), which showed excellent efficacy with endomicroscopy-guided PTT/PDT through the combination of active tumour targeting and enzyme-triggered release of 5-ALA and Cy5.5 in a PANC1-CSTE orthotopic tumour model [172] (Fig. 4). Here, CTSE is linked to neoplasm.