Polymeric nanoparticles have demonstrated to be good candidates as vehicles of drugs or molecules for combined treatment and diagnosis of cancer. In comparison with inorganic nanoparticulated systems, they present remarkable benefits in terms of stability, biocompatibility, biodegradability, tailorability and low cost. Polymeric nanoparticles can be design to passively or actively accumulate in tumor sites by controlling their hydrodynamic properties or functionalizing their surface with targeting molecules. Moreover, polymers responding to particular tumor microenvironment conditions like reduced pH, high levels of reactive oxygen species or overexpressed enzymes, can be used to trigger a controlled drug delivery, a contrast agent exposure, or to enhance the therapeutic effect of a theranostic system.
This chapter focuses on the most recent advances in this field by discussing in depth examples of nanoparticles that, exploiting all these strategies, can be visualized with one or more imaging techniques: optical imaging, MRI, US, PA, PET, SPECT or CT; and present therapeutic effect (i.e. chemotherapy, gene therapy, photothermal or photodynamic therapy) due to the presence of active moieties.