Atomically Thin Nanoribbons by Exfoliation of Hydrogen-Bonded Organic Frameworks for Drug Delivery

The currently involved two-dimensional materials (2DMs) are referred to as atomically thin-layered materials, which are composed of in-plane covalent or coordinated crystalline sheets with different chemical compositions and crystal structures. However, if the crystalline sheets supported by in-plane noncovalent intermolecular interactions, such as hydrogen-bonding, van der Waals, etc., can be exfoliated into stable atomically thin nanosheets, then the category and members of the 2DM family will be expanded significantly and extensively. Here we demonstrate that, through an ultrasonic force-assisted top-down fabrication technology in the aqueous solution, the three-dimensional hydrogen-bonded organic framework (HOF) TCPP-1,3-DPP, which is composed of one-dimensional (1D) porous ribbons that are held together via robust hydrogen-bonding contacts, can be exfoliated into atomically thin 1D porous nanoribbons (nr-HOF), providing a fine-dispersed stable colloidal suspension with a significant Tyndall effect and ultrahigh surface sensitivity. In addition, the fully exposed surface and strong surface adsorption ability of nr-HOF account for the high loading capacity of doxorubicin (Doxo; 29.4%, nr-HOF@Doxo), providing a smart carrier for an anticancer drug featuring the desired synergistic chemotherapy–photodynamic therapy–photothermal therapy effects that is more effective than the commercial Doxo drug, with a cell viability as low as 1.3%. All of these results have demonstrated brand-new 2DMs with appealing properties and applications.