In one example, gold NPs (AuNPs) were used as carrier and fluorescence quencher for FRET based tumor imaging and light manipulated on‐demand drug release.49 As shown in Figure 4A, PEG tethered with a PS (PpIX) is conjugated to β‐Cyclodextrin‐SS (b‐CD‐SS) modified AuNPs via an MMP‐2 responsive peptide linker (PLGVR). This evidence concerns the gene MMP2 and neoplasm.