Stable biocompatible cross-linked fluorescent polymeric nanoparticles based on AIE dye and itaconic anhydride

•Stable cross-linked polymeric fluorescent nanoparticles (PFNs) were covalently constructed.•Itaconic anhydride was utilized as a renewable resource.•The PFNs emitted intense fluorescence due to the introduction of aggregation induced emission dye.•The PFNs were stable below critical micelle concentration owing to the cross-liked architecture.•The PFNs were promising for cell imaging.

Self-assembly of polymeric materials to form nanoparticles is a particularly promising strategy for various biomedical applications, however, these self-assembling systems often encounter the critical micelle concentration (CMC) issue, as the nanoparticles is usually unstable at low concentration. Therefore, stable cross-linked fluorescent polymeric nanoparticles (FPNs) were covalently constructed from an aggregation induced emission (AIE) dye, itaconic anhydride, poly(ethylene glycol) monomethyl ether methacylate and polyethylenimine. These obtained PhE-ITA-20%(80%) FPNs were fully characterized by a series of techniques including 1H NMR spectra, UV–vis absorption spectra, fluorescence spectra, FT-IR spectra, transmission electron microscopy, gel permeation chromatography, and dynamic light scattering. Such FPNs emitted intense fluorescence due to the introduction of aggregation induced emission dye. More importantly, the FPNs were found extremely stable in physiological solution even below the CMC owing to their cross-linked architectures. Biocompatibility evaluation and cell uptake behavior of the FPNs were further investigated to explore their potential biomedical applications, the demonstrated excellent biocompatibility made them promising for cell imaging.

Graphical abstractStable cross-linked polymeric fluorescent nanoparticles (PhE-ITA-20%(80%)) were covalently constructed from itaconic anhydride, an aggregation induced emission dye, poly(ethylene glycol) monomethyl ether methacylate and polyethylenimine, then were fully characterized and investigated for cell imaging application.Figure optionsDownload full-size imageDownload as PowerPoint slide