Cyclodextrins (CDs), which are a class of cyclic oligosaccharides extracted from the enzymatic degradation of starch, are often utilized in molecular recognition and assembly constructs, primarily via host-guest interactions in water. In this review, recent progress in CD-based supramolecular nanoassemblies that are sensitive to chemical, biological, and physical stimuli is updated and reviewed, and intriguing examples of the biological functions of these nanoassemblies are presented, including pH- and redox-responsive drug and gene delivery, enzyme-activated specific cargo release, photoswitchable morphological interconversion, microtubular aggregation, and cell-cell communication, as well as a geomagnetism-controlled nanosystem for the suppression of tumor invasion and metastasis. Moreover, future perspectives and challenges in the fabrication of intelligent CD-based biofunctional materials are also discussed at the end of this review, which is expected to promote the translational development of these nanomaterials in the biomedical field.

Cyclodextrin-Based Multistimuli-Responsive Supramolecular Assemblies and Their Biological Functions.

J.W., N.G.K., and S.G. contributed equally to this work. This project received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska‐Curie grant agreement No 713690. This publication was also emanated from research conducted with the financial support of Science Foundation Ireland (SFI) and is co‐funded under the European Regional Development Fund under Grant Number 13/RC/2073. S.G. would like to thank India's Ministry of Chemicals and Fertilizers for NIPER Ph.D. fellowship. The authors would also like to thank Maciej Doczyk for his help with the graphic illustrations and Anthony Sloan (Technical Writer‐English) for his careful help in finalizing the manuscript.

https://www.onlinelibrary.wiley.com/doi/epdf/10.1002/adfm.201909049

Recent Advances in Host–Guest Self-Assembled Cyclodextrin Carriers: Implications for Responsive Drug Delivery and Biomedical Engineering

Chemically inert, mechanically tough, cationic metallo-polyelectrolytes were conceptualized and designed as durable anion-exchange membranes (AEMs). Ring-opening metathesis polymerization (ROMP) of cobaltocenium-containing cyclooctene with triazole as the only linker group, followed by backbone hydrogenation, led to a new class of AEMs with a polyethylene-like framework and alkaline-stable cobaltocenium cation for ion transport. These AEMs exhibited excellent thermal, chemical and mechanical stability, as well as high ion conductivity.

Cationic Metallo-Polyelectrolytes for Robust Alkaline Anion-Exchange Membranes.

Since the development of metallopolymers, there has been tremendous interest in the applications of this type of materials. The interest in these materials stems from their potential use in industry as catalysts, biomedical agents in healthcare, energy storage and production as well as climate change mitigation. The past two decades have clearly shown exponential growth in the development of many new classes of metallopolymers that address these issues. Today, metallopolymers are considered to be at the forefront for discovering new and sustainable heterogeneous catalysts, therapeutics for drug-resistant diseases, energy storage and photovoltaics, molecular barometers and thermometers, as well as carbon dioxide sequesters. The focus of this review is to highlight the advances in design of metallopolymers with specific sustainable applications.

Metallopolymers for advanced sustainable applications

Hydrogel-based flexible strain sensors have shown great potential in body movement tracking, early disease diagnosis, noninvasive treatment, electronic skins, and soft robotics. The good self-healing, biocompatible, sensitive and stretchable properties are the focus of hydrogel-based flexible strain sensors. Dual network (DN) hydrogels are hopeful to fabricate self-healing hydrogels with the above properties. Here, multifunctional DN hydrogels are prepared via a combination of host-guest interaction of β-cyclodextrin and ferrocene with dynamic borate ester bonds of poly(vinyl alcohol) and borax. Carbon nanotubes are used to endow the DN hydrogels with good conductivity. The obtained DN composite hydrogels possess good biocompatibility, stretchability (436%), fracture strength (41.0 KPa), self-healing property (healing efficiency of 95%), and high tensile strain sensitivity (gauge factor of 5.9). The DN composite hydrogels are used as flexible strain sensors to detect different human motions. After cutting, the healed hydrogels also can monitor human motions and have good stability. In addition, the hydrogel sensors may track the respiratory movement of a pig lung in vitro. This work exhibits new ideas and approaches to develop multifunctional self-healing hydrogels for constructing flexible strain sensors.

Multifunctional Self-Healing Dual Network Hydrogels Constructed via Host-Guest Interaction and Dynamic Covalent Bond as Wearable Strain Sensors for Monitoring Human and Organ Motions.

Redox-stimuli-responsive drug delivery systems with supramolecular ferrocenyl-containing polymers for controlled release

Metallomacromolecules containing cobalt sandwich complexes: Synthesis and functional materials properties

Gallol-containing homopolymers and block copolymers: ROMP synthesis and gelation properties by metal-coordination and oxidation

Controlled ROMP Synthesis of Ferrocene-Containing Amphiphilic Dendronized Diblock Copolymers as Redox-Controlled Polymer Carriers

We present the controlled synthesis of the polynorbornene-based well-defined block copolymer PNFc-b-PNAd side-chain containing ferrocene (Fc) and adamantane (Ad) units by the ring-opening metathesis polymerization using the 3rd generation Grubbs catalyst A polycationic amphiphilic block copolymer PNFcium-b-PNAd was then fabricated by the stoichiometric oxidation of Fc into ferricinium (Fcium) cations, and its redox-controlled reversible self-assembly behavior in water was demonstrated by SEM and DLS with glutathione as reductant and FeCl3 as oxidant By using benzocaine (BA) as model cargo, the loading ability of the cationic micelles formed by PNFcium-b-PNAd was investigated and confirmed, and the reduction of Fcium could lead to the rapid release of loaded payloads A new supramolecular copolymer PNFc-b-PNAd@β-CD was further prepared by simply mixing PNFc-b-PNAd and β-cyclodextrin (β-CD) with equimolar quantity to Ad units, in which host-guest interactions were mainly observed between β-CD and pendant Ad Owing to the formation of hydrophilic inclusion complexes, PNFc-b-PNAd@β-CD possesses amphiphilic property and exhibits redox-controlled self-assembly behavior in water, too The oxidation-triggered release of loaded-BA from the supramolecular micelles was observed in a slow and durable way The present novel redox-responsive micelles provide innovative examples of rational design for stimuli-responsive carriers by using Fc-containing polymers

Controlled ROMP synthesis of side-chain ferrocene and adamantane-containing diblock copolymer for the construction of redox-responsive micellar carriers

Li Zhang

Papers

Redox-stimuli-responsive drug delivery systems with supramolecular ferrocenyl-containing polymers for controlled release

Metallomacromolecules containing cobalt sandwich complexes: Synthesis and functional materials properties

Gallol-containing homopolymers and block copolymers: ROMP synthesis and gelation properties by metal-coordination and oxidation

Controlled ROMP Synthesis of Ferrocene-Containing Amphiphilic Dendronized Diblock Copolymers as Redox-Controlled Polymer Carriers

Controlled ROMP synthesis of side-chain ferrocene and adamantane-containing diblock copolymer for the construction of redox-responsive micellar carriers