Figure 3.

pH-activatable multimodal imaging by amine protonation. a) PMNs were composed of ESIONs that were self-assembled with a Ce6 and imidazole containing ligands. In a reversible process, the imidazole in the PMNs was protonated as the pH of the environment decreased, causing the nanosystem to swell and ultimately disassemble, as shown in TEM images. b,c) As a result, both the MR contrast and FL intensity of PMNs were dependent upon pH. e,f) InS-NP and InS-NP/Ce6 are nonresponsive probes that demonstrate the advantages of the pH-activated PMNs. Reproduced with permission.^[29] Copyright 2014, American Chemical Society.