posted on 2019-11-08, 14:37authored byQun Guan, Le-Le Zhou, Yan-An Li, Wen-Yan Li, Shumei Wang, Chun Song, Yu-Bin Dong
Despite
the excellent photodynamic and photothermal properties
of organic molecular photosensitizers (PSs) and photothermal agents
(PTAs), such as porphyrin and naphthalocyanine, their poor water solubility
severely impedes their biological applications. Covalent organic frameworks
(COFs), as an emerging class of organic crystalline porous materials,
possess free active end groups (bonding defects) and large inner pores,
which make them an ideal type of nanocarriers for loading hydrophobic
organic molecular PSs and PTAs by both bonding defect functionalization
(BDF) and guest encapsulation approaches to obtain multifunctional
nanomedicines for PDT/PTT combination therapy. In this work, we report
a nanoscale COF (NCOF) prepared via a facile synthetic
approach under ambient conditions. Furthermore, a dual-modal PDT/PTT
therapeutic nanoagent, VONc@COF-Por (3), is successfully
fabricated by stepwise BDF and guest encapsulation processes. The
covalently grafted porphyrinic PS (Por) and the noncovalently loaded
naphthalocyanine PTA (VONc) are independently responsible for the
PDT and PTT functionalities of the nanoagent. Upon visible (red LED)
and NIR (808 nm laser) irradiation, VONc@COF-Por (3)
displayed high 1O2 generation and photothermal
conversion ability (55.9%), consequently providing an excellent combined
PDT/PTT therapeutic effect on inhibiting MCF-7 tumor cell proliferation
and metastasis, which was well evidenced by in vitro and in vivo experiments. We believe that the results
obtained herein can significantly promote the development of NCOF-based
multifunctional nanomedicines for biomedical applications.