Masaki Nakahata

Expanding the useful lifespan of materials is becoming highly desirable, and self-healing and self-repairing materials may become valuable commodities. The formation of supramolecular materials through host-guest interactions is a powerful method to create non-conventional materials. Here we report the formation of supramolecular hydrogels and their redox-responsive and self-healing properties due to host-guest interactions. We employ cyclodextrin (CD) as a host molecule because it is environmen

Flexible, tough, and self-healable polymeric materials are promising to be a solution to the energy problem by substituting for conventional heavy materials. A fusion of supramolecular chemistry and polymer chemistry is a powerful method to create such intelligent materials. Here, a supramolecular polymeric material using multipoint molecular recognition between cyclodextrin (CD) and hydrophobic guest molecules at polymer side chain is reported. A transparent, flexible, and tough hydrogel (host-

A supramolecular hydrogel is formed by a water-soluble polymer cross-linked with host–guest inclusion complexes between cyclodextrin and ferrocene. Dissociation and re-formation of inclusion complexes by redox stimuli lead to macroscale expansion and contraction of the hydrogel. The gel is utilized as a redox-responsive actuator and the mechanical work done is evaluated. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials

Ein supramolekulares Hydrogel entsteht aus einem wasserlöslichen Polymer, das über Wirt-Gast-Einschlusskomplexe zwischen Cyclodextrin und Ferrocen vernetzt ist. Die Dissoziation und Neubildung von Einschlusskomplexen durch Redoxstimuli führte zur makroskaligen Ausdehnung und Kontraktion des Hydrogels. Das Gel wird als redoxaktiver Aktuator verwendet, und die mechanische Arbeit konnte ermittelt werden.

The macroscopic self-assembly of polymeric hydrogels modified with β-cyclodextrin (βCD gel), ferrocene (Fc gel), and styrenesulfonic acid sodium salt (SSNa gel) was investigated. Under reductive conditions, the Fc gel selectively adhered to the βCD gel through a host-guest interaction. On the other hand, the oxidized ferrocenium (Fc(+)) gel selectively adhered to the SSNa gel through an ionic interaction under oxidative conditions. The adhesion strength was estimated by a tensile test. We finall

The interaction between poly(acrylamide) gels carrying phenylboronic acid (PB gel) and catechol moieties (CAT gel) respectively is investigated. The PB gel forms an assembly with the CAT gel on a macroscopic scale in basic aqueous media. The adhesion strength is estimated by stress-strain measurements. The assembly and disassembly of the gels are reversibly switched by varying the pH of the medium. The adhesion strength is tunable by competitive monosaccharide molecules in accordance with the as

Abstract Ample evidence has demonstrated that biological cells not only react to biochemical cues from the surrounding microenvironments but also sensitively detect the mechanical properties of the extracellular matrix and neighboring cells to adapt their shape, function, and fate. Mechanical aspects in biology, called mechanobiology, have been attracting biologists, chemists, physicists, and mechanical engineers. However, most in vitro studies to date have heavily relied on covalently cross-lin

Smart design of polymeric materials may lead to intelligent materials exhibiting unique functional properties. Looking at nature, living systems use specific and reversible intermolecular interactions in realizing complex functions. Hence reversible bonds based on selective molecular recognition can impart artificial materials with unique functional properties. This review mainly focuses on supramolecular polymeric materials based on cyclodextrin-based host-guest interactions. Polymeric material

We have created a selective macroscopic self-assembly process by using polymer gels modified with complementary DNA oligonucleotides or nucleobases. The hydrogels modified with complementary DNA oligonucleotides adhered to each other by simple contact. The organogels modified with complementary nucleobases selectively formed macroscopic assemblies by agitation in nonpolar organic solvents. The adhesion strength of each gel was estimated semi-quantitatively by stress-strain measurements. We achie

Access to clean water, hygiene, and sanitation is becoming an increasingly pressing global demand, particularly owing to rapid population growth and urbanization. Phytoremediation utilizes a highly conserved phytochelatin in plants, which captures hazardous heavy metal ions from aquatic environments and sequesters them in vacuoles. Herein, we report the design of phytochelatin-inspired copolymers containing carboxylate and thiolate moieties. Titration calorimetry results indicate that the coexis

Abstract The macroscopic self‐assembly of polymeric hydrogels modified with β‐cyclodextrin (βCD gel), ferrocene (Fc gel), and styrenesulfonic acid sodium salt (SSNa gel) was investigated. Under reductive conditions, the Fc gel selectively adhered to the βCD gel through a host–guest interaction. On the other hand, the oxidized ferrocenium (Fc + ) gel selectively adhered to the SSNa gel through an ionic interaction under oxidative conditions. The adhesion strength was estimated by a tensile test.

Anion recognition in water by synthetic host molecules is a popular and challenging topic. It has been considered difficult because the water molecules compete for the recognition units. In this study, we have successfully created a novel macrocycle that achieves precise recognition through multipoint hydrogen bonding in harmony with water molecules. Specifically, an <i>N</i>-methylpyridinium amide β-cyclodextrin (β-CD) derivative 1(OTf)₇ was synthesized, whose amide groups are direct

In the field of tissue engineering, fibroblast growth factor-2 (FGF-2) effectively regenerates damaged tissue and restores its biological function. However, FGF-2 readily diffuses and degrades under physiological conditions. Therefore, methods for the sustained and localized delivery of FGF-2 are needed. Drug delivery systems using hydrogels as carriers have attracted significant interest. Injectable hydrogels with an affinity for FGF-2 are candidates for FGF-2 delivery systems. In this study, w

Abstract Boronic acids are not only a substrate for metal‐catalyzed cross‐coupling but also a molecular recognition tool. Especially, boronic acid‐diol or boronate‐diol interactions have been used to construct molecular‐scale self‐assemblies. This focus review summarizes recent researches using boronic acids as a bridge between similar or dissimilar (macro)molecules to build functional hybrid materials. Functional properties of boronic acid moieties such as molecular selectivity and stimuli‐resp