Polymerizable AEE-active Dye with Optical Activity for Fluorescent Nanoparticles Based on Phenothiazine: Synthesis, Self-assembly and Biological Imaging

In consideration of various advantages such as less harm, higher sensitivity, and deeper imaging depth, etc. , AIE materials with longwave emission are attracting extensive attention in the fields of vascular visualization, organelle imaging, cells tracker, forensic detection, bioprobe and chemosensor, etc. In this work, a novel fluorescent ( R )-PVHMA monomer with chirality and aggregation-induced emission enhancement (AEE) characteristics was acquired through enzymatic transesterification reaction basing on phenothiazine, and its [ α ] D 25°C value was about −6.39° with a 3.08 eV bandgap calculated by the quantum calculations. Afterwards, a series of PEG-PVH1 and PEG-PVH2 copolymers with chirality feature were achieved through RAFT polymerization of the obtained ( R )-PVHMA and PEGMA with various feed ratios. When the feed molar ratio of ( R )-PVHMA increased from 21.5% to 29.6%, its actual molar fractions in the PEG-PVH1 and PEG-PVH2 copolymers accordingly increased from 18.1% to 25.7%. The molecular weight of PEG-PVH1 was about 2.2×10 4 with a narrow PDI, and their kinetics estimation showed a first-order quasilinear procedure. In aqueous solution, the amphiphilic copolymers PEG-PVH could self-assemble into about 100 nm nanoparticles. In a 90% water solution of H 2 O and THF mixture, the fluorescence intensity had the maximum value, and the emission wavelength presented at 580 and 630 nm. The investigation of cytotoxicity and cells uptake showed that PEG-PVH FONs performed outstanding biocompatibility and excellent cells absorption effects, which have great potential in bioimaging application.