Fluorescent Polymer Nanoparticle for Selective Sensing of Intracellular Hydrogen Peroxide

Fluorescent boronate-modified polyacrylonitrile (BPAN) nanoparticles of 50 nm diameter were fabricated for use as a selective H2O2 sensor. The fluorescence intensity changed and an emission peak shifted when BPAN nanoparticles selectively interacted with H2O2, relative to other reactive oxygen species (ROS). The BPAN nanoparticles undergo photoinduced electron transfer (PET) between a Schiff base moiety and boronate, which enhances the fluorescence and makes the nanoparticles suitable for selective ROS recognition. We demonstrate the use of these nanoparticles as a detector of endogenous H2O2 produced in living cells. The representative features of the fluorescent BPAN nanoparticles that make them particularly attractive for H2O2 and ROS detection are the following: they are easily synthesized as PET sensors; they exhibit a characteristic emission peak and peak shift that distinguishes reaction with H2O2 from other ROS; and compared to organic compounds, the sensing moiety on BPAN polymer nanoparticles is more thermally stable and has superior mechanical properties, enabling their use in various biomedical applications.