Imparting multi-functionality to covalent organic framework nanoparticles by the dual-ligand assistant encapsulation strategy

The potential applications of covalent organic frameworks (COFs) can be further developed by encapsulating functional nanoparticles within the frameworks. However, the synthesis of monodispersed core@shell structured COF nanocomposites without agglomeration remains a significant challenge. Herein, we present a versatile dual-ligand assistant strategy for interfacial growth of COFs on the functional nanoparticles with abundant physicochemical properties. Regardless of the composition, geometry or surface properties of the core, the obtained core@shell structured nanocomposites with controllable shell-thickness are very uniform without agglomeration. The derived bowl-shape, yolk@shell, core@satellites@shell nanostructures can also be fabricated delicately. As a promising type of photosensitizer for photodynamic therapy (PDT), the porphyrin-based COFs were grown onto upconversion nanoparticles (UCNPs). With the assistance of the near-infrared (NIR) to visible optical property of UCNPs core and the intrinsic porosity of COF shell, the core@shell nanocomposites can be applied as a nanoplatform for NIR-activated PDT with deep tissue penetration and chemotherapeutic drug delivery. Despite many reports on nanoparticle-covalent organic frameworks (COF) composites, a universal strategy for the synthesis of monodisperse core-shell structured COF nanocomposites remains challenging. Here, the authors develop a strategy for interfacial growth of highly crystalline COFs on functional nanoparticles with abundant optical, electrical and magnetic properties.

Automated summary

A universal strategy for the synthesis of monodisperse core-shell structured COF nanocomposites remains challenging. The authors have developed a versatile dual-ligand assistant strategy for interfacial growth of COFs on functional nanoparticles with various properties for potential applications in PDT and chemotherapeutic drug delivery. The core@shell structured nanocomposites exhibit controllable shell-thickness and uniformity without agglomeration, making them promising for NIR-activated PDT with deep tissue penetration.