Radioiodinated tyrosine based carbon dots with efficient renal clearance for single photon emission computed tomography of tumor

Abstract

Nanoparticles with effective tumor accumulation and efficient renal clearance have attracted significant interests for clinical applications. We prepared 2.5 nm tyrosine based carbon dots (TCDs) with phenolic hydroxyl groups on the surface for directly 125I labeling. The 125I labeled polyethylene glycol (PEG) functionalized TCDs (125I-TCDPEGs) showed excellent radiochemical stability both in vitro and in vivo. Due to the enhanced permeability and retention effect, these 125I-TCDPEGs demonstrated a tumor accumulation around 4%–5% of the injected dose per gram (ID/g) for U87MG, 4T1, HepG2 and MCF7 tumor-bearing mice at 1 h post-injection. Meanwhile, the 125I-TCDPEGs also could be fast renally excreted, with less than 0.6% ID/g left in the liver and spleen within 24 h. These radioactive carbon dots not only can be used for cellular fluorescence imaging due to their intrinsic optical property, but are also effective single photon emission computed tomography (SPECT) imaging agents for tumor. Together with their excellent biocompatibility and stability, we anticipate these 125I-TCDPEGs of great potential for early tumor diagnosis in clinic. What’s more, our TCDPEGs are also proved to be feasible carriers for other iodine isotopes such as 127I and 131I for different biomedical application.