Dye encapsulated polymeric nanoprobes for in vitro and in vivo fluorescence imaging in panchromatic range

Abstract

Pluronic (R) triblock copolymers, which spontaneously form nano-sized aggregates in water, have been considered as promising carriers for bioimaging and drug delivery. However, their use for applications in pharmacology and diagnostics is hindered by instability of polymer aggregates which are easily dissociated into unimers. Here we report a general method for stabilizing Pluronic (R) F127 micelles via semi-interpenetrating network (sIPN). The formation of sIPN within a core stabilizes the micelle upon temperature and concentration changes. We determined optimized methods for the preparation of F127 sIPN in the regime of chemical components. Importantly, F127 sIPNs are able to load various organic fluorescence probes, covering a panchromatic range of photoluminescence (350-850 nm; entire UV-Vis-NIR), without compromising their photophysical properties. Moreover, efficient cellular uptake of the fluorescence probes loaded sIPN is observed in human and mouse cells. After intravenous injection into mice, an infrared dye-loaded sIPNs are incorporated in multiple organs and have longer lifetime than a commercially available imaging probe. With the improvement of stability, Pluronic micelles with sIPN can be a powerful tool for building functional nanoprobes and in vivo fluorescence imaging for cancer cells and live animals.