Synthesis of amphiphilic fluorescent PEGylated AIE nanoparticles via RAFT polymerization and their cell imaging applications

Abstract

With the increasing interest in the use of luminescent probes in biomedical applications, the development of fluorescent organic nanoparticles (FONs) on the basis of aggregation induced emission (AIE) dyes has attracted great research attention. In this study, a polymerizable tetraphenylethene-functionalized AIE dye (named as TPEV) with a vinyl end functional group was synthesized by a “one-step” Suzuki coupling reaction of 4-vinylphenylboronic acid and bromotriphenylethylene, and the as-prepared hydrophobic AIE dye TPEV subsequently participated in the reversible addition–fragmentation chain transfer (RAFT) polymerization together with the hydrophilic monomer of poly(ethylene glycol) monomethacrylate (PEGMA) to obtain a new amphiphilic copolymer (denoted as TPEV–PEG) with transformed side fluorescent groups. The M_n value of the obtained copolymer was about 29 800 g mol⁻¹ with a narrow polydispersity index (PDI) of about 1.30. The molar ratio of TPE to PEG segment in the copolymer was respectively about 19.2% to 80.8%, and it was easy for the TPEV–PEG copolymer to self-assemble into FONs with the hydrophobic AIE core encapsulated by a hydrophilic PEG shell. The research results further showed that the TPEV–PEG FONs presented good fluorescent features with the maximal emission peak at 480 nm, high dispersibility in water solution with homogeneous spherical morphology (∼200 nm) and excellent biocompatibility, giving them good potential for bioimaging applications.