Fig. 2

a Schematic illustration of the synthetic procedure of AuNS@BSA/I-MMP2 NPs and their applications, b TEM image of AuNS@BSA/I-MMP2 NPs, c in vivo NIR fluorescence images of mice bearing A549 tumors after injection of AuNS@BSA/I-MMP2 NPs (excitation = 710 nm, emission = 790 nm), d PA images of AuNS@BSA/I-MMP2 NPs treated mice at different time intervals (excitation = 780 nm). Reproduced with permission from [116]. Copyright ©2019, Elsevier