Oxidation-Responsive Polymeric Fluorinated Nanoparticles Prepared by Polymerization-Induced Self-Assembly

Responsive polymeric nanoparticles have been extensively studied for various biological applications to provide enhanced function accuracy. Here, we report the synthesis of oxidation-responsive polymeric fluorinated nanoparticles (FNPs) via a photopolymerization-induced self-assembly (photo-PISA) method using a thioether- and fluorine-containing monomer N-(2-((2,2,2-trifluoroethyl)-thio)-ethyl)-acrylamide (FTAM) and a methoxy polyethylene glycol (mPEG)-based macro chain transfer agent. With the polymerization of FTAM, the resultant block copolymer mPEG-b-PFTAM undergoes spontaneous self-assembly into spherical nanoparticles, driven by the solvophobic nature of the PFTAM block. The mobility of fluorine spins is highly restricted in the nanoparticles, leading to diminished 19F nuclear magnetic resonance (NMR)/magnetic resonance imaging (MRI) signals. However, when the nanoparticles are exposed to oxidants, the hydrophobic thioether groups of PFTAM can be oxidized into hydrophilic sulfoxide groups. This transition can lead to the disassembly of the PISA nanoparticles and switching on of the F-19 NMR/MRI signals, owing to increased mobility of the fluorinated segments. This oxidation-responsive capability makes these polymeric FNPs useful for applications associated with oxidative conditions.