Three‐Dimensionalsp²Carbon‐LinkedCovalent Organic Frameworks as a Drug Carrier Combined with Fluorescence Imaging

Abstract

Three-dimensional (3D) covalent organic frameworks (COFs) are crystalline porous polymers with potential in numerous high-tech applications, but the linkages involved in their synthesis are still rather limited. Herein, we report novel 3D sp 2 carbon-linked COFs fabricated by the formation reaction of C=C bonds and their application in fluorescence imaging. These new COFs, namely JUC-580 and JUC-581, show high stability and excellent light-emitting properties in solid state and dispersed in various solvents. Furthermore, we investigate the potential application of JUC-581 as a drug carrier combined with fluorescence imaging. These results indicate that 3D sp 2 carbon-linked COFs are not only potential drug-loaded and sustained release materials but also promising cell fluorescent stains. This study thus expands the structural categories of 3D COFs based on different linkages, and promotes their prospective applications for biomedicine and fluorescent materials.

Carbon–Carbon Linked Organic Frameworks: An Explicit Summary and Analysis

“…Till now, very limited examples of CC linked COFs have been reported. [ 94,95 ] As we have already discussed, as the chain needs to propagate in all three dimensions, the limited reversibility of CC bond formation mostly leads to amorphous frameworks. But, 3D COFs are more suitable for applications like charge transport.…”

“…In 2022, Liao et al reported two interesting 3D sp 2 carbon linked COFs, namely JUC‐580 and JUC‐581, through Knoevenagel condensation of tetrakis(4‐formylphenyl)silane (TFS) as a tetrahedral building unit, and 2,2′‐(1,4‐phenylene)diacetonitrile (PDAN) or 2,2′‐(biphenyl‐4,4′‐diyl)diacetonitrile (BPDAN) as 2D linkers. [ 95 ] Both COFs possessed large channels, permanent porosity, and excellent thermal and chemical stability. They showed luminescence in solid state and even suspended in various solvents.…”

“…The fluorescence lifetimes for JUC‐580 and JUC‐581 were calculated to be 28.81 and 28.07 ns, respectively. [ 95 ] COFs with similar morphology were synthesized through the Schiff‐base reaction pathway resulting in 3D imine linked materials; they were found to be inefficient in photo‐luminescence, conveying the future of vinylene linked organic frameworks in the optical field. In addition, the authors also showed the potential application of JUC‐581 as a drug carrier combined with bioresponsive fluorescence imaging.…”

An ionic vinylene-linked three-dimensional covalent organic framework for selective and efficient trapping of ReO4− or 99TcO4−

“…The irreversible of C = C bond enables the framework to exhibit impressive stability under harsh conditions, and offers extended π conjugation throughout the framework for efficient electron transport, showing great potential applications in photocatalysis 20 – 23 . So far, the only example of 3D sp 2 carbon-linked COFs involves substituted acrylonitrile [−CH = C(CN)−] based on the Knoevenagel condensation between arylacetonitriles and aromatic aldehydes 17 , 24 . Nevertheless, the strong electron-withdrawing substitution of nitriles attached to the olefin bond makes the bond reversible, compromising the stability and the crystallinity of COFs 25 .…”

Design of size uniform and controllable covalent organic framework nanoparticles for high-performance anticancer drug delivery

“…Through dedicated structural designs, many other functions, including photothermal/dynamic, sonodynamic, photoluminescence, can also be introduced into the COF nanocarrier to design the ondemand smart drug delivery systems. [23][24][25] Over the years, COF materials have been explored for potential drug delivery applications. E.g.…”