Construction of Multiform Hollow-Structured Covalent Organic Frameworks via a Facile and Universal Strategy for Enhanced Sonodynamic Cancer Therapy

The special structural morphology of hollow covalent organic frameworks (HCOFs) has an important influence on their applications. However, the rapid and precise control of morphology for HCOFs still remains largely challenging. Herein, we present a facile and universal two-step strategy based on solvent evaporation and oxidation of imine bond for the controllable synthesis of HCOFs. The strategy enables to prepare HCOFs in a greatly shortened reaction time and seven kinds of HCOFs are fabricated by the oxidation of imine bond via hydroxyl radicals (.OH) generated from Fenton reaction. Importantly, a fascinating library of HCOFs with diverse nanostructures, including bowl-like, yolk-shell, capsule-like and flower-like morphologies, has been ingeniously constructed. Owing to the large cavities, the obtained HCOFs are ideal candidates for drug delivery, which are employed to load five small molecule drugs, achieving the enhanced sonodynamic cancer therapy in vivo.

Automated summary

The special structural morphology of hollow covalent organic frameworks (HCOFs) has a significant impact on their applications. However, the precise control of morphology for HCOFs remains challenging. In this study, a two-step strategy based on solvent evaporation and oxidation of imine bond is presented, enabling the controllable synthesis of HCOFs. The oxidation of imine bond via hydroxyl radicals (.OH) generated from Fenton reaction results in the construction of seven kinds of HCOFs with diverse nanostructures, including bowl-like, yolk-shell, capsule-like, and flower-like morphologies. The obtained HCOFs, with their large cavities, are ideal candidates for drug delivery and have been successfully used for enhanced sonodynamic cancer therapy in vivo.