Butyrylcholinesterase Responsive Supramolecular Prodrug with Targeted Near‐infrared Cellular Imaging Property

Multifunctional application of supramolecular cucurbiturils as encapsulating hosts in drug delivery: A review

Cucurbit[n]uril (CB[n], n = 5-10), a unique category of molecular hosts composed of n glycoluril units, has attracted considerable attention because of its exceptional molecular recognition properties. Cucurbit[n]urils represent an innovative category of molecular containers capable of forming stable complexes with a wide array of guests, including pharmaceutical compounds, amino acids, proteins or peptides, saccharides, and dyes, among others. Compared to the chemistry of calixarenes and cyclodextrins, the advancement of CB[n] chemistry has been rather sluggish until recently. This is mainly due to their inadequate solubility in typical solvents and the difficulties involved in functionalising these compounds. Cucurbiturils are characterised as water-soluble, symmetrical, rigid host molecules with a pumpkin-like form. The distinctiveness of cucurbiturils facilitates the encapsulation of diverse pharmacological molecules, both neutral and positively charged, via non-covalent interactions, yielding femtomolar affinities. This feature article summarises numerous studies conducted by researchers on the applicability of cucurbiturils and their derivatives in targeted medication delivery and controlled drug release. In vitro and in vivo experiments indicate that cucurbit[n]urils possess negligible systemic toxicity, exhibit specific organ toxicity, and do not seem to affect embryonic biology. Drug delivery methods that improve upon those of other supramolecular host molecules, especially cyclodextrins, and alternative formulation systems like polymers, hydrogels, and liposomes are anticipated to be developed as a result of the increasing fascination with cucurbituril-based systems, which are known for their low acute toxicity. The case studies show a wide range of usage, from basic research to translational uses in fields including gene therapies, antibiotics, and chemotherapy, among others.

Macrocyclic Supramolecular Assemblies Based on Hyaluronic Acid and Their Biological Applications

Hyaluronic acid (HA), which contains multiple carboxyl, hydroxyl, and acetylamino groups and is an agent that targets tumors, has drawn great attention in supramolecular diagnosis and treatment research. It can not only assemble directly with macrocyclic host-guest complexes through hydrogen bonding and electrostatic interactions but also can be modified with macrocyclic compounds or functional guest molecules by an amidation reaction and used for further assembly. Macrocycles play a main role in the construction of supramolecular drug carriers, targeted imaging agents, and hydrogels, such as cyclodextrins and cucurbit[n]urils, which can encapsulate photosensitizers, drugs, or other functional guest molecules via host-guest interactions. Therefore, the formed supramolecular assemblies can respond to various stimuli, such as enzymes, light, electricity, and magnetism for controlled drug delivery, enhance the luminescence intensity of the assembly, and improve drug loading capacity. In addition, the nanosupramolecular assembly formed with HA can also improve the biocompatibility of drugs, reduce drug toxicity and side effects, and enhance cell permeability; thus, the assembly has extensive application value in biomedical research. This Account mainly focuses on macrocyclic supramolecular assemblies based on HA, especially their biological applications and progress in the field, and these assemblies include (i) guest-modified HA, such as pyridinium-, adamantane-, peptide-, and other functional-group-modified HA, along with their cyclodextrin and cucurbit[n]uril assemblies; (ii) macrocycle-modified HA, such as HA modified with cyclodextrins and cucurbit[n]uril derivatives and their assembly with various guests; (iii) direct assembly between unmodified HA and cyclodextrin- or cucurbit[n]uril-based host-guest complexes. Particularly, we discussed the important role of macrocyclic host-guest complexes in HA-based supramolecular assembly, and the roles included improving the water solubility and efficacy of hydrophobic drugs, enhancing the luminescent intensity of assemblies, inducing room temperature phosphorescence and providing energy transfer systems, constructing multi-stimulus-responsive supramolecular assemblies, and in situ formation of hydrogels. Additionally, we believe that obtaining in-depth knowledge of these HA-based macrocyclic supramolecular assemblies and their biological applications encompasses many challenges regarding drug carriers, targeted imaging agents, wound healing, and biomedical soft materials and would certainly contribute to the rapid development of supramolecular diagnosis and treatment.