Effect of core diameter, surface coating, and PEG chain length on the biodistribution of persistent luminescence nanoparticles in mice.

A growing insight toward optical sensors has led to several major improvements in the development of convenient probes for in vivo imaging. Efficient optical detection using quantum dots (QDs) as well as near-infrared organic dyes relies on several key driving principles: the ability to lower background absorption or autofluorescence from tissue, a good photostability of the probe, and a high quantum yield. In this article, we report the real-time biodistribution monitoring of lanthanide-doped persistent luminescence nanoparticles (PLNP), emitting in the near-infrared window, in healthy and tumor-bearing mice. We focused on the influence of hydrodynamic diameter, ranging from 80 to 180 nm, and polyethylene glycol (PEG) surface coating on the behavior of our probes. Tissue distribution was found to be highly dependent on surface coverage as well as core diameter. The amount of PLNP in the blood was highly increased for small (d < 80 nm) and stealth particles. On the opposite, PEG shield molecular weight, ranging from 5 to 20 kDa, had only negligible influence on the in vivo biodistribution of our silicate-based material.