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. Author manuscript; available in PMC: 2015 Oct 14.
Published in final edited form as: J Drug Target. 2012 Sep 26;21(1):1–26. doi: 10.3109/1061186X.2012.723213

Figure 6.

Figure 6

(A) The structure of Activatable Cell Penetrating Peptide-conjugated Dendrimer (ACPPD). Multiple ACPPs are covalently attached via the polycationic segments (a) to the dendrimer (gray circle). Yellow ovals (d) demonstrated the payloads such as Cy5 and/or Gd. Upon exposure to MMP-2 or -9 in tumor microenvironment, the linkers (b) are cleaved and polyanions (c) are released, leaving the cationic dendrimers for cell entry. (B–E) The enhanced uptake of Gd and Cy5 dually labeled ACPPDs in regions with high MMP activities and infiltrative tumors. (B–C) Axial MR and fluorescence images of a transgenic PyMT mouse before surgery (white arrows: the tumor burdens); (D–E) Axial MR and fluorescence images of the same mouse after surgical removal of tumor under white light. Red arrows: regions of residual hyperintensity on MR and fluorescence imaging; (F) Regions of hyperintensity on MRI were removed under fluorescence imaging and stained with hematoxylin/eosin to verify the presence of tumor. Adapted with permission from Olson et al. (2010).