Ultrasmall Hyperbranched Semiconducting Polymer Nanoparticles with Different Radioisotopes Labeling for Cancer Theranostics.

Exploiting ultrasmall nanoparticles as multifunctional nanocarriers labeled with different radionuclides for tumor theranostics has attracted great attention in past few years. Herein, we develop multifunctional nanocarriers based on ultrasmall hyperbranched semiconducting polymer (HSP) nanoparticles for different radionuclides including technetium-99m (99mTc), iodine-131 (131I), and iodine-125 (125I) labeling. SPECT imaging of 99mTc labeled PEGylated HSP nanoparticles (HSP-PEG) exhibit a prominent accumulation in two-independent tumor models including subcutaneously xenograft and patient derived xenograft model. Impressively, 5,6-dimethylxanthenone-4-acetic acid (DMXAA), as tumor-vascular disrupting agent (VDA), significantly improves the tumor accumulation of 131I labeled HSP-PEG nanoparticles, further leading to the excellent inhibition of tumor growth after intravenous injection. More importantly, SPECT imaging of 125I labeled HSP-PEG indicates that ultrasmall HSP-PEG nanoparticles could be slowly excreted from the body of a mouse through urine and feces in 1 week and cause no obvious toxicity to treated mice from blood analysis and histology examinations. Our finding from the different independent tumor models SPECT imaging shows that HSP-PEG nanoparticles may act as multifunctional nanocarriers to deliver different radionuclides for monitoring the in vivo behaviors of nanoparticles and cancer theranostics, which will provide a strategy for cancer treatment.