Manganese oxides are of considerable importance in technological applications, including ion-exchange, molecular adsorption, catalysis, and electrochemical supercapacitors owing to their structural flexibility combined with novel chemical and physical properties. [1][2][3][4][5] Up to now, various nanostructures of MnO 2 , such as nanoparticles, [6] nanorods/-belts/-wires/-tubes/-fibers, [7][8][9][10][11] nanosheets, [12] mesoporous/molecular sieves and branched structures, [13,14] urchins/orchids, and other hierarchical structures [15] have been synthesized by different methods.Over the past years, fabrication of hierarchical hollow nanostructures has attracted significant interest because of their widespread potential applications in catalysis, drug delivery, acoustic insulation, photonic crystals, [16][17][18][19][20] and other areas. Until now, the general approach for preparation of hollow structures has involved the use of various removable or sacrificial templates, referred to as "hard", such as monodispersed silica, [21,22] polymer latex spheres [23] and reducing metal nanoparticles, [24] as well as "soft" ones, for example, emulsion droplets/ micelles [25] and gas bubbles. [26] Furthermore, lots of one-pot template-free methods for generating hollow inorganic microand nanostructures have been developed employing novel mechanisms, including the nanoscale corrosion-based insideout evacuation [27] and Kirkendall effect. [28] Recently, rhombododecahedral silver cages have been prepared by self-assembly coupled with the precursor crystal-templating approach. [29] By treating the external morphologies of hollow structures, unique properties can be obtained. [30] Thus, it is desirable to develop easy methods to control the morphologies of assembled systems with well-defined hierarchical structures. Herein, we report a simple controlled preparation of hierarchical hollow microspheres and microcubes of MnO 2 nanosheets through self-assembly with an intermediate crystaltemplating process. As shown in Figure 1, the synthesis is performed by a three-step process. Particularly, discrete spherical and cubic hollow MnO 2 nanostructures with controlled morphologies can be prepared by changing the morphologies of MnCO 3 precursors, which can be simply obtained by adding the (NH 4 ) 2 SO 4 solution in the reaction system, and the thicknesses of the shells of hierarchical hollow nanostructures can be adjusted easily by the relative quantities of KMnO 4 reacted followed by selective removal of MnCO 3 crystal template with HCl. When used as adsorbent in waste-water treatment, as-prepared MnO 2 with a hierarchical hollow nanostructure exhibited a good ability to remove organic pollutant.Some related chemical reactions are shown as follows. The main chemical reaction (1) can be formulated with two half reactions. On the basis of the value of E°, the standard Gibbs free energy change DG°of reaction (1) could be estimated as -99.0 kJ mol -1 , implying strong tendency for reaction (1) to progress toward the right-hand side. As ...

mechanisms operate with excellent fl exibility/adaptability originating from cooperation of multiple dynamic systems. [ 1 ] In most cases, the functional components of these systems are assembled through non-covalent dynamic interactions. Although their assembled structures are often ambiguous, or "fuzzy," functions of biological systems are signifi cantly superior to any of the so far precisely constructed artifi cial machines and devices. Thus, fabrication of bio-like systems might be one of the ultimate goals of the science and technology of functional materials. There has already been some success in the synthesis of excellent new materials, [ 2 ] but these are still far inferior to biological materials systems from the point-of-view of specifi city, effi ciency, and adaptability, although incremental progress involving existing technological concepts may not change this situation. A certain paradigm shift in construction concepts of functional materials is necessary to establish an advanced approach towards truly dynamic functions.Fabrication of functional materials requires control of organization of their components with nanometer precision. The novel technological concept of nanotechnology has been established over the past few decades with a view to exploit nanometer-sized phenomena and to fabricate functional materials by precisely controlling the materials' structures at the nanoscale. [ 3 ] Several strategies of nanotechnology are simple extensions of the corresponding successful microtechnologies to nanofabrication. However, the control of nanoscale events and structures requires different approaches to those commonly applied in microtechnology. This is because physical phenomena at the nanoscale are quite different from microscopic phenomena. Effects occurring at the microscopic level are often similar to those occurring in the macroscopic regime. In contrast, nanoscale phenomena involving nanometer-sized objects are strongly infl uenced by thermal/statistical fl uctuations, mutual interactions, and possibly quantum effects between components. In many cases, such mutual actions are dynamically integrated, often resulting in unexpected properties and effects so that components of nanoscale systems cannot be controlled by intuitive means. To understand and therefore control nanoscale phenomena and to Objects in all dimensions are subject to translational dynamism and dynamic mutual interactions, and the ability to exert control over these events is one of the keys to the synthesis of functional materials. For the development of materials with truly dynamic functionalities, a paradigm shift from "nanotechnology" to "nanoarchitectonics" is proposed, with the aim of design and preparation of functional materials through dynamic harmonization of atomic-/molecular-level manipulation and control, chemical nanofabrication, self-organization, and fi eld-controlled organization. Here, various examples of dynamic functional materials are presented from the atom/molecularlevel to macroscopic dimensions. Thes...

A new bioconjugate nanostructure was constructed by using photosensitizer-incorporated mixed lipid-coated gold nanocages for two-photon photothermal/photodynamic cancer therapy in vitro with high efficiency. Scanning electron microscopic and transmission electron microscopic images reveal that the precursors and bioconjugate nanostructure as-prepared are narrowly dispersed and possess uniform morphologies. The relevant energy dispersion X-ray analysis and UV-vis spectra indicate that the bioconjugate nanostructure above was assembled successfully and has a strong absorption in the near-infrared region. Fluorescence and electronic spin resonance results show that the gold nanocage in the bioconjugate nanostructure can dramatically quench the photosensitizer and inhibit the production of singlet oxygen, which is supposed to alleviate the photosensitizers' unwanted side effects originating from their nontargeted distribution. We have demonstrated that as the nanocomplex is internalized by cancer cells, under two-photon illumination, photodynamic anticancer treatment is dramatically enhanced by the photothermal effect.

No abstract

No abstract

Small aldehyde molecule are demonstrated to induce cationic diphenylalanine to assemble into monodisperse enzyme‐responsive nanocarriers with high biocompatibility and excellent biodegradability. The formation of Schiff base covalent bond and accompanying π–π interaction of aromatic rings are found to be the mainly driving forces for the assembly of the nanocarriers. Interestingly, the nanocarriers show autofluorescence due to the n–π* transitions of C = N bonds, which lends them visually traceable property in living cells. Importantly, the nanocarriers can be taken in by cells and biodegraded in the cells. In addition, doxorubicin is easily loaded into the nanocarriers with high encapsulation amount, and its release can be triggered by tyrisin under physiological conditions. Noticeably, even at a very low drug concentration, the doxorubicin‐loaded nanocarriers still exhibit a much higher killing capacity of HeLa cells in vitro, compared to the equivalent‐dose free doxorubicin, indicating they have a great potential biomedical application.

Biocompatible and biodegradable microcapsules were fabricated by the covalent assembly of polysaccharides and their derivatives. The formation of Schiff's bases between polysaccharides and their derivatives enabled the microcapsules' autofluorescence properties and pH-responsivity. These polysaccharide microcapsules have great potential applications in biological tracing and drug delivery.

Adenosine triphosphate (ATP) is one of the most important energy sources in living cells, which can drive serial key biochemical processes. However, generation of a proton gradient for ATP production in an artificial way poses a great challenge. In nature, photophosphorylation occurring in chloroplasts is an ideal prototype of ATP production. In this paper we imitate the light-to-ATP conversion process occurring in the thylakoid membrane by construction of FoF1-ATPase proteoliposome-coated PSII-based microspheres with well-defined core@shell structures using molecular assembly. Under light illumination, PSII can split water into protons, oxygen, and electrons and can generate a proton gradient for ATPase to produce ATP. Thus, an artificially designed chloroplast for PSII-driven ATP synthesis is realized. This biomimetic system will help to understand the photophosphorylation process and may facilitate the development of ATP-driven devices by remote light control.