Figure 2

Chemical structures of the five designed probes.

1, 1-Scr and 1-D are Gd-based T₁ MR CAs. 1 is susceptive to furin, while 1-D is the condensation product of 1 after furin cleavage. 1-Scr is the scrambled control probe of 1. 2 is the Eu analog of 1 for TPLM cell imaging. 2-Scr is the Eu analog of 1-Scr.