AIE-based donor–acceptor–donor fluorenone compound as multi-functional luminescence materials

Abstract

The development of novel luminescent materials with multi-stimuli responsive and multi-functional properties is required. In this work, we designed and synthesized a novel AIE-based fluorenone derivative, MBPF. The donor–acceptor–donor (D–A–D) structure promoted the intermolecular hydrogen bonding capacity of the exposed oxygen atom in fluorenone. MBPF displayed three different aggregation morphologies: an amorphous floccule Y-MBPF with yellow-green luminescence, a block crystal O-MBPF with orange luminescence, and a needlelike crystal R-MBPF with red emission. They all exhibited reversible stimuli-response phase transitions to temperature and shear, accompanied by fluorescence switching. The orange crystal O-MBPF was also sensitive to isotropic hydrostatic pressure with prominent and contrasting luminescent conversion. Furthermore, we prepared MBPF nanocrystallites and encapsulated them with DSPE–PEG and the monoclonal antibody cetuximab (C225) to obtain MBPF-C225 NPs, which were biocompatible and photostable. They could be used for specific cancer cell imaging through receptor-mediated endocytosis.