Profluorescent PPV-Based Micellar System as a Versatile Probe for Bioimaging and Drug Delivery

Although micelles are commonly used for drug delivery purposes, their long-term fate is often unknown due to photobleaching of the fluorescent labels or the use of toxic materials. Here, we present a metal-free, nontoxic, nonbleaching, fluorescent micelle that can address these shortcomings. A simple, yet versatile, profluorescent micellar system, built from amphiphilic poly(p-phenylenevinylene) (PPV) block copolymers, for use in drug delivery applications is introduced. Polymer micelles made from PPV show excellent stability for up to 1 year and are successfully loaded with anticancer drugs (curcumin or doxorubicin) without requiring introduction of physical or chemical cross-links. The micelles are taken up efficiently by the cells, which triggers disassembly, releasing the encapsulated material. Disassembly of the micelles and drug release is conveniently monitored as fluorescence of the single polymer chains appear, which enables not only to monitor the release of the payload, but in principle also the fate of the polymer over longer periods of time.