Development of Natural-Drugs-Based Low-Molecular-Weight Supramolecular Gels

Natural small molecular drugs with excellent biocompatibility, diverse pharmacological activities, and wide sources play an increasingly important role in the development of new drug and disease treatment. In recent years, the utilization of paclitaxel, camptothecin, rhein, curcumin, and other natural small molecular drugs with unique rigid backbone structures and modifiable multiple sites as building blocks to form gels by self-assembly has attracted widespread attention. The obtained low-molecular-weight supramolecular gel not only retains the general characteristics of the gel but also overcomes the shortcomings of natural drugs, such as poor water solubility and low bioavailability. It has the advantages of high drug loading, low toxicity, and outstanding stimulus responsiveness, which is widely used in biomedical fields. Here, we provided a comprehensive review of natural-drugs-based low-molecular-weight supramolecular gels reported in recent years and summarized their assembly mechanism, gel structure, gel properties, and potential applications. It is expected to provide a reference for further research of natural-drugs-based supramolecular gels.

Supramolecular Gels Based on Azobenzene Derivatives

In the past years, azobenzene, as a common photoreactive group, has been widely used in intelligent photocontrolled supramolecular gels. In the field of biomedicine, a few supramolecular hydrogels based on azobenzene are regarded as carriers with low damage and high control in vivo due to their advantages in light response. In the environmental field, some hydrogels can also adsorb pollutants under the control of light through the interaction between host and guest. At the same time, supramolecular hydrogels based on azobenzene with multiple stimulus responses have been studied. It is difficult for most supramolecular organogels to have multiple stimulus responses simultaneously and the preparation conditions are also more complex. In this paper, I have summarized the latest research results of supramolecular hydrogels and organogels based on azobenzene in recent years so that researchers can have a deeper understanding of the preparation methods, properties and application of the supramolecular gels containing azobenzene.