Conjugated Polymers with Aggregation‐Induced Emission Characteristics for Fluorescence Imaging and Photodynamic Therapy

Abstract

Accurate diagnosis and treatment have been extensively developed in the field of biomedicine, which put forward higher requirements for the development of biomedical materials with high efficiency and selectivity. Among them, conjugated polymers featuring aggregation‐induced emission (AIE) characteristics (AIE conjugated polymers) have stood out in recent years owing to their unique properties, such as intense solid emission, high light‐harvesting ability, efficient energy transfer, and high 1O2 generation ability, which empower them with effective biomedical functions in fluorescence imaging (FLI), photodynamic therapy (PDT), FLI‐guided PDT, two‐photon excited photodynamic therapy (2PE‐PDT), etc. In this review, we highlight recent progress in AIE conjugated polymers and their applications in anticancer and antibacterial areas based on FLI and PDT, and summarize the mechanism of color‐tuned fluorescence emission and efficient 1O2 generation ability. The challenges and perspectives for the future development of AIE conjugated polymers are also discussed.

Design for a Pure-Blue-Emissive Polymer Film through the Selective Perturbation of the Energy Level of the Highest Occupied Molecular Orbital in a Boron Complex

“…However, carrier transferring, which is another essential character for obtaining high efficiency in optoelectronic devices, could be disturbed. Another promising approach is the application of aggregation-induced emission (AIE)-active materials, which can show enhanced emission efficiency in the solid state. − Emission properties of AIE-active molecules can be explained by the degree of molecular motions in the excited state . Because of vigorous molecular motions in the solution state, emission quenching proceeds, meanwhile emission property can be preserved even in the solid by suppressing energy-consumable molecular motions and concentration quenching with steric hindrances of the substituents.…”

Molecular Engineering Design of Enhanced Donor–Acceptor Therapeutic Reagent for Efficient Image‐Guided Photodynamic Therapy

“…[14e,19] Unfortunately, their low upconversion luminescence quantum yield, which ranges from 0.005% to 0.3%, restricts their application for tumor imaging. [ 20 ] Conjugated polymers seem to solve the issues faced by the above‐mentioned donor materials and have attracted widespread attention in tumor image‐guided PDT due to their superior light‐harvesting capability, great photostability, extraordinary biocompatibility, good energy transfer efficiency, [ 21 ] and comparably large Stokes shift (>200 nm). [ 15c ] Therefore, it is the best option to choose conjugated polymers as the donor in the D–A structure because they overcome the drawbacks of other donor types, significantly increase the acceptor's singlet oxygen yield and fluorescence efficiency, as well as the Stokes shift, displaying great promise for the future of biological image‐guided PDT.…”

Vision Defense: Efficient Antibacterial AIEgens Induced Early Immune Response for Bacterial Endophthalmitis

“…[17,18] In recent few years, aggregation-induced emission luminogens (AIEgens) have successfully showed the great potential as promising PSs. [19][20][21][22][23][24] Because of the restriction of intramolecular motions, AIEgens could be induced to give intense emission and generate efficient ROS in the aggregates, while show weak emission in the monomer state. [25] Some photodynamic materials have been used in bacteria killing strategy of wounds, such as semiconductors and inorganic nanoparticles.…”