Fig. 3.

Evaluation of the ability of nChain particles to target metastasis in vivo. (a) The timeline of surgery and BLI imaging are shown with respect to implantation of 4T1 cancer cells into the mammary fat pad of female BALB/c mice. Representative BLI images of an untreated animal indicate the progression of metastatic disease. (b) Representative FMT images of the same mouse show the accumulation of nChain particles in lung metastasis at 2 h post-injection. The nChain particles were injected 11 days after surgical removal of primary tumor (25 days after tumor inoculation), which was the time point of early onset of lung metastasis. (c) Using an NIR fluorophore as a label, the time-course of nanoparticle accumulation in lung metastases was obtained by quantification of the fluorescence signal in the FMT images of mice injected with nChain, integrin-targeting liposome (Lip) and non-targeting liposome (NT-Lip) at a DOX dose of 0.5 mg/kg b.w. (n=4 mice in each group; * P<0.02 by Student’s t-test). The lungs of the animals injected with nChain were excised and digested 5 h after administration and the iron concentration was measured using ICP-OES (data point indicated as ICP in the graph). Control animals were used to correct for background levels of endogenous iron. (d) Using a CRi Maestro fluorescence imaging system, ex vivo imaging of lungs 5 h after injection indicated the colocalization of nChain particles and 4T1 metastatic cells expressing GFP.