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The booming development of nanomedicine offers great opportunities for cancer diagnostics and therapeutics. Herein, a magnetic targeting-enhanced cancer theranostic strategy using a multifunctional magnetic-plasmonic nano-agent is developed, and a highly effective in vivo tumor photothermal therapy, which is carefully planed based on magnetic resonance (MR)/photoacoustic (PA) multimodal imaging, is realized. By applying an external magnetic field (MF) focused on the targeted tumor, a magnetic targeting mediated enhanced permeability and retention (MT-EPR) effect is observed. While MR scanning provides tumor localization and reveals time-dependent tumor homing of nanoparticles for therapeutic planning, photoacoustic imaging with higher spatial resolution allows noninvasive fine tumor margin delineation and vivid visualization of three dimensional distributions of theranostic nanoparticles inside the tumor. Utilizing the near-infrared (NIR) plasmonic absorbance of those nanoparticles, selective photothermal tumor ablation, whose efficacy is predicted by real-time infrared thermal imaging intra-therapeutically, is carried out and then monitored by MR imaging for post-treatment prognosis. Overall, this study illustrates the concept of imaging-guided MF-targeted photothermal therapy based on a multifunctional nano-agent, aiming at optimizing therapeutic planning to achieve the most efficient cancer therapy. [ABSTRACT FROM AUTHOR]

Recently, near-infrared (NIR) absorbing conjugated polymeric nanoparticles have received significant attention in photothermal therapy of cancer. Herein, polypyrrole (PPy), a NIR-absorbing conjugate polymer, is used to coat ultra-small iron oxide nanoparticles (IONPs), obtaining multifunctional IONP@PPy nanocomposite which is further modified by the biocompatible polyethylene glycol (PEG) through a layer-by-layer method to acquire high stability in physiological solutions. Utilizing the optical and magnetic properties of the yielded IONP@PPy-PEG nanoparticles, in vivo magnetic resonance (MR) and photoacoustic imaging of tumor-bearing mice are conducted, revealing strong tumor uptake of those nanoparticles after intravenous injection. In vivo photothermal therapy is then designed and carried out, achieving excellent tumor ablation therapeutic effect in mice experiments. These results promise the use of multifunctional NIR-absorbing organic-inorganic hybrid nanomaterials, such as IONP@PPy-PEG presented here, for potential applications in cancer theranostics. [ABSTRACT FROM AUTHOR]