Fig. 4: Quantitative imaging of extracellular and intracellular distribution of nanoparticles in different tumors.

a The pre- and post-irradiated Cy5 fluorescence images, calculated extracellular Cy5 fluorescence images, and the ratiometric images of extracellular signals versus post-irradiated fluorescence signals of 4T1 tumor-bearing mice at different time points post-injection of MRIN. b The time-dependent profile of intracellular, extracellular, and total nanoparticle exposure in 4T1 tumor sites over 96 h (n = 4 biologically independent mice). c The percentages of intracellular and extracellular distributions of MRIN as well as the ratio of extracellular exposure to intracellular ones in 4T1 tumor sites over 96 h (n = 4 biologically independent mice). d The intracellular, extracellular, total distribution of nanoparticles in tumor sections at 24 h post-injection of MRIN. The merged image showed the unambiguous differentiation of extracellular and intracellular nanoparticles. The ratiometric images of intracellular exposure of nanoparticles were also calculated. e Dissecting the intracellular and extracellular distribution of NPs in different tumors at 24 h post-injection of MRIN. f Heat map shows the percentages of extracellular nanoparticles in various tumor models at 24 h post-injection of MRIN (n = 3 biologically independent mice). g The quantitative intracellular and extracellular nanoparticle exposure in different tumors at different time post-injection (n = 3 biologically independent mice). The percentages of extracellular nanoparticles ranged from 50-80% of total accumulated NPs over 24 h. All data were presented as mean ± s.d.