In Situ Visualization of Reversible Diels–Alder Reactions with Self-Reporting Aggregation-Induced Emission Luminogens

Abstract

The dynamic reversible Diels–Alder (DA) reactions play essential roles in both academic and applied fields. Currently, in situ visualization and direct monitoring of the formation and cleavage of covalent bonds in DA reactions are hampered by finite compatibility and expensive precise instruments, especially limited in solid reactions. We herein report a fluorescence system capable of in situ visualization by naked eyes and monitoring DA/retro-DA reactions. With the fluorescence quenching effect, the synthesized TPEMI could work as an innovative self-indicator for both DA termination and retro-DA occurrence. The fluorescence increases during DA reactions, and the mechanism is investigated to establish qualitative and quantitative relations. Besides rapid screening of reaction conditions and monitoring of DA exchange processes, the TPEMI fluorescence system can visualize heterogeneous and solid-state reactions with the AIE character. The TPEMI platform is expected to offer novel insights into reversible DA processes and dynamic covalent chemistry.

In Situ Imaging and Anti-inflammation of 3D Printed Scaffolds enabled by AIEgen

“…While, conventional organic fluorophores with planar structures often experience notorious aggregation-induced quenching (ACQ) emission in the aggregated state, which limits their biological applications. Compared to ACQ, aggregation-induced emission-active luminogens (AIEgens) with high photostability, good biocompatibility and high emission efficiency in the aggregated state have attracted large attention in biomedical fields [39][40][41][42][43][44][45], which makes AIEgens are ideal indicator for in situobservation of scaffolds in vivo. Furthermore, AIEgens with aggregation-enhanced reactive oxygen species (ROS) generation have achieved great progress in the field of antibacterial treatment by virtue of photodynamic therapy (PDT).…”

In Situ Imaging and Anti-inflammation of 3D Printed Scaffolds Enabled by AIEgen

“…While conventional organic fluorophores with planar structures often experience notorious aggregation-induced quenching (ACQ) emission in the aggregated state, which limits their biological applications. Compared to ACQ, aggregation-induced emission-active luminogens (AIEgens) with high photostability, good biocompatibility, and high emission efficiency in the aggregated state have attracted large attention in biomedical fields, − which makes AIEgens ideal indicators for the in situ observation of scaffolds in vivo. Furthermore, AIEgens with aggregation-enhanced reactive oxygen species (ROS) generation have achieved great progress in the field of antibacterial treatment by virtue of photodynamic therapy (PDT). − Nevertheless, few reports about AIEgens inhibiting bacterial infection and bio-imaging on the 3D scaffolds are presented.…”

Reversible fluorescent adhesives based on covalent adaptable networks with dynamic AIE crosslinking: in situ visualization of adhesion capability

“…Given the dynamic nature of reversible bonds, they can be repeatedly ruptured and reformed under various stimuli. 19,20 Motivated by attractive properties, a series of dynamic chemistries including the Diels-Alder (DA) reaction, 21,22 disulfide metathesis, 23,24 and photo-dimerization 25,26 have been applied for removable and reversible adhesives. However, the dynamic nature of these bonds also brings the shortcoming that the mechanical strength of the adhesives can be easily affected by environmental changes or inadvertent operations during daily use.…”

“…It is nonemissive in both the solution and solid-state due to the photo-induced electron transfer (PET) process between maleimide (MI) and tetraphenylethene (TPE). 23,33 However, the DA reaction between TPE-2MI and the furan group of FEP can disturb the PET process and release the AIE behavior of TPE. As cross-linking goes on, the integration of TPE into the polymer networks can inherently restrict the intramolecular rotation of TPE to enhance its emission, which can be visualized.…”