Highly Effective Generation of Singlet Oxygen by an Imidazole-Linked Robust Photosensitizing Covalent Organic Framework

• Published in: ACS nano Vol. 16; no. 12; pp. 21565 - 21575
• Main Authors: Luan, Tian-Xiang, Du, Lehan, Wang, Jia-Rui, Li, Keyu, Zhang, Quan, Li, Pei-Zhou, Zhao, Yanli
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 27.12.2022
• Subjects: Imidazoles - pharmacology; Metal-Organic Frameworks - chemistry; Photochemotherapy; Photosensitizing Agents - chemistry; Photosensitizing Agents - pharmacology; Porphyrins - chemistry; Porphyrins - pharmacology; Singlet Oxygen; covalent organic frameworks; imidazole linkage; porphyrin; singlet oxygen; photodynamic therapy
• ISSN: 1936-0851; 1936-086X; 1936-086X
• DOI: 10.1021/acsnano.2c10423

Developing effective photosensitizers to initiate the generation of singlet oxygen (1O2) is of great significance in both chemistry and physiology. Herein, linking the photoactive porphyrin moieties by in situ-formed robust imidazole groups, a covalent organic framework (COF), PyPor-COF, was successfully designed and synthesized. Detailed characterizations reveal that it not only possesses high crystallinity, permanent porosity, and robust stability but also shows a semiconductive photoresponse activity. As demonstrated by electron paramagnetic resonance experiments, the COF can initiate the generation of 1O2 efficiently under visible-light irradiation, the efficiency of which is higher than that of the pristine porphyrin-based reactant and even higher than some commonly used commercially available photosensitizing agents. Anticancer experiments prove that it can efficiently trigger the production of 1O2 in a physiological environment. This work demonstrates that the imidazole-linked porphyrin-incorporated COF is a highly promising photosensitizer that can even be applied in photodynamic therapy.