Iodine-Rich Polymersomes Enable Versatile SPECT/CT Imaging and Potent Radioisotope Therapy for Tumor in Vivo

ACS Appl Mater Interfaces. 2019 May 29;11(21):18953-18959. doi: 10.1021/acsami.9b04294. Epub 2019 May 15.


Emerging tumor treatment demands high sensitivity and high-spatial resolution diagnosis in combination with targeted therapy. Here, we report that iodine-rich polymersomes (I-PS) enable versatile single-photon emission computed tomography (SPECT)/computed tomography (CT) dual-modal imaging and potent radioisotope therapy for breast cancer in vivo. Interestingly, I-PS could be easily and stably labeled with radioiodine, 125I and 131I. Dynamic light scattering and transmission electron microscopy showed that 125I-PS had a size of 106 nm and vesicular morphology, similar to those of the parent I-PS. Methyl thiazolyl tetrazolium assays displayed that I-PS and 125I-PS were noncytotoxic, whereas 131I-PS caused significant death of 4T1 cells at 5 mg PS/mL with a radioactivity of 12 μCi. Pharmacokinetic and biodistribution studies showed that 125I-PS has a prolonged circulation and distributes mainly in tumor and the reticuloendothelial system. The intravenous injection of 125I-PS to 4T1 murine breast tumor-bearing mice allowed simultaneous high sensitivity and high-spatial resolution imaging of tumor by SPECT and CT, respectively. The therapeutic studies revealed that 131I-PS could effectively retard the growth of 4T1 breast tumor and significantly prolong mice survival time. The hematoxylin and eosin staining assay proved that 131I-PS induced tumor cell death. I-PS emerges as a robust and versatile platform for dual-modal imaging and targeted radioisotope therapy.

Keywords: SPECT/CT; contrast agents; polymersomes; radioisotope; theranostics.

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents / therapeutic use
  • Cell Death
  • Cell Line, Tumor
  • Iodine / chemistry*
  • Iodine / pharmacokinetics
  • Iodine Radioisotopes / pharmacokinetics
  • Mice, Inbred BALB C
  • Neoplasms / pathology
  • Neoplasms / radiotherapy*
  • Polymers / chemistry*
  • Tissue Distribution
  • Tomography, Emission-Computed, Single-Photon*
  • Tomography, X-Ray Computed*


  • Antineoplastic Agents
  • Iodine Radioisotopes
  • Polymers
  • Iodine