Synthesis of AIE-Active Materials with Their Applications for Antibacterial Activity, Specific Imaging of Mitochondrion and Image-Guided Photodynamic Therapy

Abstract

In comparison with fluorescence molecules with aggregation-caused quenching (ACQ), fluorescence molecules with aggregation-induced emission (AIE) have great advantages in cell imaging, image-guided photodynamic therapy (PDT), and antibacterial activity. However, the reasonable design and synthesis of related molecules are still of great challenges. Herein, a consecutive strategy via several reliable reactions to prepare a series of AIE-active luminogens by adjusting their structures is reported. Having concentrated on the factors for the principle purpose of 1 O 2 generation, TPA-18 is picked out within all triphenylamine (TPA) derivatives according to its longer emission wavelength (640 nm in solid), the lowest energy gap between HOMO and LUMO (calculated as 2.04 eV), the totally separated orbital distributions of HOMO and LUMO, and typical AIE characteristics. Meanwhile, owing to the presence of the positive structural charge and the bright emission color, TPA-18 in aggregated form is detected as an impressive probe for the mitochondria-targeted imaging and living zebrafish embryos imaging in vivo. Accordingly, TPA-18 can effectively generate 1 O 2 reactive oxygen species; it provides an effective application for image-guided photodynamic cancer treatment and antibacterial activity. Therefore, this study not only synthesized AIE photosensitizer with tunable emission wavelength (from blue to red color) but also raised a new concept for the constructing AIEgens with versatile applications in cell imaging, antibacterial activity, and image-guided PDT.

Recent Strategies to Develop Innovative Photosensitizers for Enhanced Photodynamic Therapy

“… Compared to 61a , 62 showed red-shifted aggregate emission (λ ems = 708 nm), higher 1 O 2 quantum yield (Φ Δ = 0.80), and superior photocytotoxicity with complete killing of HeLa cancer cells at 0.5 μM. In another study, Liu et al synthesized a library of AIEgens with triphenylamine as the central framework, which was connected to various EWGs, such as pyridinium and −CN, with or without the presence of π bridges for mitochondria targeting, imaging-guided PDT, and antibacterial activity . Among these AIEgens, 63 showed the highest photocytotoxicity toward both E. coli and S. aureus and exhibited mitochondria-targeted cell imaging at low concentrations (∼10 μM) (Figure ).…”

Insights and Perspectives Regarding Nanostructured Fluorescent Materials toward Tackling COVID-19 and Future Pandemics

“…(All figures at the same scale bar). Reproduced from ref ( 19 ). Copyright 2020 American Chemical Society.…”

PEG‐Polymer Encapsulated Aggregation‐Induced Emission Nanoparticles for Tumor Theranostics

“…The increase in ΔE ST makes production of ROS of AIE photosensitizer increase. [191] To improve anti-tumor efficiency of AIE photosensitizer, it is necessary to enhance ROS production of photo-sensitizer, increase tissue penetration depth of light and increase oxygen content in tumor, or design photosensitizer independent of oxygen content.…”