Fluorescent Nanoparticles Synthesized by Carbon-Nitride-Stabilized Pickering Emulsion Polymerization for Targeted Cancer Cell Imaging.

Graphitic carbon nitride (CN) has been found to possess amphiphilic properties, enabling it to act as a solid emulsifier to stabilize the Pickering emulsion and subsequent polymerization. Herein, we used CN-stabilized Pickering emulsion polymerization to prepare molecularly imprinted polymer nanoparticles, which showed selective binding toward cancer cells. Taking advantage of its intrinsic amphiphilicity and emission properties, CN served as both the emulsifier in the polymerization process and emissive probe for cellular imaging application. Sialic acid (SA), as an important indicator of some certain cancers, was introduced into the polymer nanoparticles by forming reversible bonds with 4-vinylphenylboronic acid comonomer and removed by adjusting the pH value. The obtained SA-imprinted polymer nanoparticles exhibited good biocompatibility and excellent targeted imaging of DU 145 cells, which are prostate cancer cells having an SA-overexpressed surface. This work provides an easy, low-cost, low-toxicity, and large-scale strategy to prepare various functional polymer nanoparticles.