Fig 4.

In vivo multimodal imaging of cells loaded with nanoparticles. (A) Representative confocal microscopy image of DCs loaded with particles (white arrows), indicating their intracellular localization. (B) PA spectroscopy measurement in a gel phantom of nanoparticle-loaded cells (1x10⁶ cells) and free nanoparticles. (C) Different concentrations of nanoparticle-loaded cells were injected intramuscularly in vivo and imaged with PAI and fluorescence (n=3). PA data was spectrally unmixed, with green indicating the labeled cells, red oxyhemoglobin and blue deoxyhemoglobin. Furthermore, nanoparticle-loaded cells were injected into the thigh muscle and imaged with ¹⁹F MRI (n=1).