Entropy-Driven Hierarchical Nanostructures from Cooperative Self-Assembly of Gold Nanoparticles/Block Copolymers under Three-Dimensional Confinement

The cooperative self-assembly of polystyrene-<i>b</i>-poly­(4-vinylpyridine) block copolymers (BCPs) and gold nanoparticles (AuNPs) confined within the emulsion droplets is studied by combining both the experiments and Monte Carlo simulations. The results indicate that the entropic interaction between the AuNPs and BCP domain is a critical parameter to dominate the spatial arrangement of AuNPs and the nanostructure of the hybrid nanoparticles, which can be utilized to design novel hierarchical hybrid nanoparticles. Based on this theoretical observation, a large number of unique Janus hybrid nanoparticles, including pupa-like nanoparticles with AuNPs concentrated at one pole of the particles, spherical nanoparticles with AuNPs enriched in a bulge on the sphere surface, and the gourd-like, clover-like, and four-leaf-clover-like nanoparticles from the further hierarchical assembly of small hybrid Janus nanoparticles, are fabricated via three-dimensional (3D) confined self-assembly

A Switchable Helical Capsule for Encapsulation and Release of Potassium Ion

A type of aromatic helical capsules was synthesized. The crystal structure proved an inner cavity that could perform switchable encapsulation and release of potassium ion through protonation/deprotonation-mediated extension and contraction of molecular motion

Temperature-Driven Switching of the Catalytic Activity of Artificial Glutathione Peroxidase by the Shape Transition between the Nanotubes and Vesicle-like Structures

Smart supramolecular nanoenzymes with temperature-driven switching property have been successfully constructed by the self-assembly of supra-amphiphiles formed by the cyclodextrin-based host–guest chemistry. The self-assembled nanostructures were catalyst-functionalized and thermosensitively-functionalized through conveniently linking the catalytic center of glutathione peroxidase and thermosensitive polymer to the host cyclodextrin molecules.The ON–OFF switches for the peroxidase activity by reversible transformation of nanostructures from tube to sphere have been achieved through changing the temperature. We anticipate that such intelligent enzyme mimics could be developed to use in an antioxidant medicine with controlled catalytic efficiency according to the needs of the human body in the future

Construction of GPx Active Centers on Natural Protein Nanodisk/Nanotube: A New Way to Develop Artificial Nanoenzyme

Construction of catalytic centers on natural protein aggregates is a challenging topic in biomaterial and biomedicine research. Here we report a novel construction of artificial nanoenzyme with glutathione peroxidase (GPx)-like function. By engineering the surface of tobacco mosaic virus (TMV) coat protein, the main catalytic components of GPx were fabricated on TMV protein monomers. Through direct self-assembly of the functionalized viral coat proteins, the multi-GPx centers were installed on these well-defined nanodisks or nanotubes. With the help of muti-selenoenzyme centers, the resulting organized nanoenzyme exhibited remarkable GPx activity, even approaching the level of natural GPx. The antioxidation study on subcell mitochondrial level demonstrated that virus-based nanoenzyme exerted excellent capacity for protecting cell from oxidative damage. This strategy represents a new way to develop artificial nanoenzymes

Self-Assembly of Cricoid Proteins Induced by “Soft Nanoparticles”: An Approach To Design Multienzyme-Cooperative Antioxidative Systems

A strategy to construct high-ordered protein nanowires by electrostatic assembly of cricoid proteins and “soft nanoparticles” was developed. Poly(amido amine) (PAMAM) dendrimers on high generation that have been shown to be near-globular macromolecules with all of the amino groups distributing throughout the surface were ideal electropositive “soft nanoparticles” to induce electrostatic assembly of electronegative cricoid proteins. Atomic force microscopy and transmission electron microscopy all showed that one “soft nanoparticle” (generation 5 PAMAM, PD5) could electrostatically interact with two cricoid proteins (stable protein one, SP1) in an opposite orientation to form sandwich structure, further leading to self-assembled protein nanowires. The designed nanostructures could act as versatile scaffolds to develop multienzyme-cooperative antioxidative systems. By means of inducing catalytic selenocysteine and manganese porphyrin to SP1 and PD5, respectively, we successfully designed antioxidative protein nanowires with both excellent glutathione peroxidase and superoxide dismutase activities. Also, the introduction of selenocysteine and manganese porphyrin did not affect the assembly morphologies. Moreover, this multienzyme-cooperative antioxidative system exhibited excellent biological effect and low cell cytotoxicity

Construction of ATP-Switched Allosteric Antioxidant Selenoenzyme

Rational redesign of allosteric protein offers an efficient strategy to develop switchable biocatalysts. By combining the computational design and protein engineering, a glutathione peroxidase (GPx)-like active center that contains the catalytic selenocysteine (Sec) residue and substrate-binding Arg residue was precisely incorporated into the allosteric domain of adenylate kinase (AKe). The engineered selenoenzyme shows not only high GPx activity but also adenosine triphosphate (ATP)-responsive catalytic property, which is regulated by its opened to closed conformational change upon ATP binding. Theoretical and mutational analysis reveals that the synergistic effect of electrostatic interactions and van der Waals (vdW) interactions for substrate recognition is a major contribution to the high activity. The mitochondrial oxidative damage experiment further demonstrated its antioxidant ability at the subcellular level, offering a potential application toward controllable catalysis in vivo

Reductive-Responsive, Single-Molecular-Layer Polymer Nanocapsules Prepared by Lateral-Functionalized Pillar[5]arenes for Targeting Anticancer Drug Delivery

Herein, a new reductive-responsive pillar[5]­arene-based, single-molecule-layer polymer nanocapsule is constructed for drug delivery. The functionalized system shows good biocompatibility, efficient internalization into targeted cells and obvious triggered release of entrapped drugs in a reducing environment such as cytoplasm. Besides, this smart vehicle loaded with anticancer drug shows excellent inhibition for tumor cell proliferation and exhibits low side effect on normal cells. This work not only demonstrates the development of a new reductive-responsive single molecular layer polymer nanocapsule for anticancer drug targeting delivery but also extends the design of smart materials for biomedical applications