Inorganic Moieties Research Articles

Fabrication and characterization of in situ synthesized iron oxide‐modified polyimide nanoweb by needleless electrospinning

ABSTRACTA series of poly(amic acid) (PAA) solutions were prepared by sol–gel condensation of 4,4′‐oxydianiline (ODA) and 4,4′‐oxydiphthalic anhydride (ODPA), containing various wt % (5, 10, 15) of an iron oxide precursor, that is, tris(acetylacetonato)iron(III) complex. The resulting PAA solutions were electrospun at 78 kV and collected as webs of nonwoven nanofibers of diameter ∼60–70 nm and subsequently converted to iron oxide‐modified polyimide (PI) nanofibers by slow thermal imidization. Aminopropyl triethoxysilane (APTES) and tetraethoxyorthosilicate (TEOS) were used as coupling agent and silica precursor, respectively, to enhance the compatibility between organic polymer matrix and inorganic moieties. SEM images reveal smooth and defect‐free surface morphologies of the nanofibers. Superparamagnetic properties of the nanofibers were revealed by vibrating sample magnetometer (VSM). FT‐infrared spectroscopy (IR), powder XRD, thermogravimetric analysis, and differential scanning calorimetry were employed to systematically characterize material structural properties, thermal stabilities, etc. Nanowebs showed excellent thermal stability around 446°C, with a glass transition temperature around 270°C. The above study demonstrates a good example for fabrication of highly thermally stable bead‐free nanofiber webs by needleless electrospinning. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40432.

Ordered Hybrids from Template‐Free Organosilane Self‐Assembly

Despite considerable achievements over the last two decades, nonporous organic-inorganic hybrid materials are mostly amorphous, especially in the absence of solvothermal processes. The organosilane self-assembly approach is one of the few opportunities for creating a regular assembly of organic and inorganic moieties. Additionally, well-established organosilicon chemistry enables the introduction of numerous organic functionalities. The synthesis of periodically ordered hybrids relies on mono-, bis-, or multisilylated organosilane building blocks self-assembling into hybrid mesostructures or superstructures, subsequently cross-linked by siloxane Si-O-Si condensation. The general synthesis procedure is template-free and one-step. However, three concurrent processes underlie the generation of self-organized hybrid networks: thermodynamics of amphiphilic aggregation, dynamic self-assembly, and kinetically controlled sol-gel chemistry. Hence, the set of experimental conditions and the precursor structure are of paramount importance in achieving long-range order. Since the first developments in the mid-1990s, the subject has seen considerable progress leading to many innovative advanced nanomaterials providing promising applications in membranes, pollutant remediation, catalysis, conductive coatings, and optoelectronics. This work reviews, comprehensively, the primary evolution of this expanding field of research.

Functionalized large pore mesoporous silica nanoparticles for gene delivery featuring controlled release and co-delivery.

Novel mesoporous silica nanoparticles (LPMSNs) functionalised with degradable poly(2-dimethylaminoethyl acrylate) (PDMAEA) have been developed (PDMAEA-LPMSNs) as nano-carriers for gene delivery. The unique design of PDMAEA-LPMSNs has endowed this system with multiple functions derived from both the organic and inorganic moieties. The cationic polymer unit binds to genetic molecules and undergoes a self-catalyzed hydrolysis in water to form a non-toxic anionic polymer poly(acrylic acid), allowing controlled release of siRNA in the cells. The nanopores of the LPMSNs provide a reservoir for storage and release of chloroquine to facilitate endosomal escape. The PDMAEA-LPMSN composites were characterized by elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), solid-state 13C magic-angle spinning nuclear magnetic resonance (MAS-NMR), thermogravimetric analysis (TGA), and nitrogen sorption techniques. Their siRNA delivery performance was tested in a KHOS cell line, showing promising potential for co-delivery of genes and drugs.

Selectively recognizing organic semiconducting molecules on solid state molecular cages based on ZnOTCPP

In this study, we constructed a novel solid state supramolecular system-the molecular cage ZnOTCPP, based on an inorganic/organic hybrid nanostructure, through the assembly of 5,10,15,20-tetra(3-carboxyphenyl)porphyrin (TCPP) onto the surfaces of ZnO nanorod (NR) arrays. The ZnOTCPP molecular cage exhibited highly selective recognition of 5,10,15,20-tetraphenylporphyrin (TPP) by optical and photoelectrical signals. The ZnOTCPP@TPP exhibited high emission efficiency, with a six-fold increase in the intensity of the emission relative to that of ZnOTCPP after the molecular cage ZnOTCPP captured TPP. The optical, electrical, and optoelectrical properties of the molecular cage ZnOTCPP could be controlled by tuning the interactions between the guest and the host's inorganic or organic moieties. Such a solid state molecular cage opens the door to controlled-delivery applications and provides an attractive platform for studying solid state supramolecular electronics and optoelectronics.

Modification of polycarbonate with hydrophilic/hydrophobic coatings for the fabrication of microdevices

In this paper, we introduce a simple strategy for modifying the surface of polycarbonate (PC) to make it either hydrophilic or hydrophobic. The aminosilane, bis[3-(trimethoxysilyl)propyl]amine (bis-TPA), was used to produce the hydrophilic surface via aminolysis of the carbonate backbone to form strong urethane linkages, leaving alkoxysilane parts exposed on the surface. To obtain the hydrophobic surface, PC coated with bis-TPA was further reacted with (tridecafluoro-1,1,2,2-tetrahydrooctyl)-triethoxysilane (FTES), where inorganic moieties of both silanes condensed to realize siloxane (Si–O–Si) bonds. In this way, fluorinated groups were left exposed on the terminal surface of the PC, rendering it hydrophobic. In-depth surface characterizations were performed, including water contact angle measurement and X-ray photoelectron spectroscopy (XPS) analysis, in order to identify the optimum conditions for achieving surface modification without sacrificing substrate transparency. To extend the use of these PC surface treatments to microfluidic applications, the hydrophilic coating was further adopted for use in bonding two PC substrates by forming Si–O–Si bonds at the interface. Using the hydrophilic treatment of PC, we obtained microchannels, which were resistant to organic solvents. Furthermore, by employing subsequent hydrophobic treatment, multiple liquids were successfully injected into microchannels sequentially in a valve-free manner

Suzuki coupling reaction catalyzed heterogeneously by Pd(salen)/polyoxometalate compound: another example for synergistic effect of organic/inorganic hybrid

A hybrid compound consisting of palladium(salen) [salen = N,N′‐bis(salicylidene)ethylenediamine] complex covalently linked to a lacunary Keggin‐type polyoxometalate, K8[SiW11O39](POM), was synthesized and characterized by FT‐IR, elemental analysis, inductively coupled plasma and diffuse reflectance UV–visible spectroscopic methods. The hybrid, [Pd(salen)–POM], was investigated in the Suzuki cross‐coupling in EtOH/H2O under mild reaction conditions. In comparison to the corresponding organic and inorganic moiety, the hybrid has shown greatly improved catalytic activity, and much higher yields toward coupling products were obtained with a low catalyst loading for various aryl halides, including unreactive and sterically hindered ones. The catalyst also exhibited prominent recyclable performance and no obvious loss of activity was observed after six consecutive runs. Copyright © 2013 John Wiley & Sons, Ltd.

Sulfonated mesoporous benzene-silica-embedded sulfonated poly(ether ether ketone) membranes for enhanced proton conduction and anti-dehydration

In polymer electrolyte fuel cell operation, a decrease in the proton conductivity of the membrane at reduced humidity is a main cause for poor cell performance at high temperature. To alleviate the dehydration of the membrane at high temperature, sulfonated mesoporous benzene-silica (sMBS) particles are embedded in sulfonated poly(ether ether ketone) (sPEEK) membranes. As the sMBS itself is highly sulfonated on both organic and inorganic moieties, the proton conductivity of composite membranes is much higher than that of the pristine sPEEK membrane, and it reaches that of Nafion 117 at a high relative humidity (RH) of 90%. The dehydration rate of the membrane is reduced significantly by the capillary condensation effect of sMBS particles with the nanometer-scale 2-D hexagonal cylindrical pores, and the proton conductivity of the composite membranes, 0.234 × 10−1 S cm−1, is much higher than that of pristine sPEEK membrane, 0.59 × 10−3 S cm−1, at a relatively low humidity of 40% RH. This maintenance of high conductivity at low humidity is attributed to the high water-holding capacity of the sMBS proton conductors. The sMBS-embedded sPEEK composite membranes show a much lower methanol permeability of 2–5 × 10−7 cm2 s−1 compared to that of Nafion 117, which is 1.6 × 10−6 cm2 s−1 at room temperature.

The subtle effect of methyl substituent in C2-symmetric template on the formation of halocluster hybrids

Six novel haloclusters, namely {[dmb]2[Cu4I8]}·2DMF (1), {[ddb][Cu4I6]}n (2), {[dmb][Ag2I4]}n (3), {[ddb][Ag4I6]}n (4), {[dmb]2[Ag2Br6]} (5) and {[ddb][Ag4Br6]}n (6), were encountered in our investigation of the subtle template effect of methyl substituent on the formation of hybrids. The dications we chosen as C2-symmetric template is α,α′-di(3-methylimidozole-1-yl)benzene dichloride (abbreviated into dmb) or α,α′-di(2,3-dimethylimidozole-1-yl)benzene dichloride (abbreviated into ddb). The X-ray crystallography shows the more methyl substituents that exist in template, the more inorganic/organic interactions form in the hybrid net oriented by ddb. It is the H-bonds and electrostatic interactions between the organic counteractions and inorganic moieties that do the contribution to the crystal packing. These compounds have been further characterized by IR spectroscopy, UV–Vis spectra and thermostability properties.

Synthesis and Structural Characterization of Cation-Induced Complex: [Cd4(SCN)6(BPB)]n With One-Dimensional Double Helix

In this study, colorless crystals of the title inorganic-organic hybrid compound were obtained from the solution-phase reaction of cadmium thiocyanate with BPB·Br2 in MeOH/DMF(BPB·Br2 = 1,4-bis(pyridinium)butane dibromine). And single-crystal X-ray diffraction analysis revealed that this polymer crystallized in triclinic, space group P–1 with unit cell parameters a = 5.8855(5) Å, b = 9.5996(8) Å, c = 11.4358(9) Å, α = 69.9710(10)°, β = 75.1100 (10)°, γ = 75.8180(10)°. In this compound, each cadmium atom is octahedrally coordinated in 2S4N geometry and doubly bridged infinite one-dimensional double helix cadmium thiocyanate chains act as inorganic moiety with dication discretely surrounded. Supplemental materials are available for this article. Go to the publisher's online edition of Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry to view the supplemental file.

Hybrid biodegradable membranes of silane-treated chitosan/soy protein for biomedical applications

In recent years, progress in the field of hybrid materials has been accelerated through use of the sol–gel process for creating materials and devices, which benefit from the incorporation of both inorganic and organic components. In this work, organic–inorganic hybrid membranes were prepared from tetraethoxysilane and a blend system composed of chitosan and soy protein. By introducing a small amount of siloxane bond into the chitosan/soy protein system, the chitosan/soy protein hybrid membranes were improved in terms of structure, topography and mechanical properties. It appears that the chitosan/soy protein hybrid membranes were formed by discrete inorganic moieties entrapped in the chitosan/soy protein blend, which improved the stability and mechanical performance assessed by the dynamic mechanical analysis as compared to chitosan/soy protein membrane. Also, in vitro cell culture studies evidenced that the chitosan/soy protein hybrid membranes are non-cytotoxic over a mouse fibroblast-like cell line. The hybrid membranes of silane-treated chitosan/soy protein developed in this work have potential in biomedical applications, including tissue engineering.

Ethylenediamine as a bridging ligand: structure solution of two cadmium(II)-based coordination polymers from powder diffraction data

Structures of [Cd(C2H8N2)Cl2]n(1) and [Cd(C2H8N2)Br2]n(2) were solved from powder diffraction data. Compound (1) crystallizes in the space group Pbam (No. 55), a = 9.9021(7) Å, b = 7.8186(6) Å, c = 4.0705(3) Å, V = 315.13(3) Å3, Z = 2. (2) is isostructural: space group Pbam (No. 55), a = 10.405(2) Å, b = 7.8634(8) Å, c = 4.2079(5) Å, V = 344.28(6) Å3, Z = 2. The investigated compounds are examples of two-dimensional hybrid coordination polymers, in which neighboring metal centers are bridged via both organic and inorganic moieties: ethylenediamine molecules and halide anions. Both crystal structures were solved ab initio from powder data using direct methods.

Adhesion enhancement of 316L stainless steel to acrylic bone cement through nanocomposite sol–gel coating system

A nanocomposite hybrid coating was synthesised from tetraethylethoxysilane and 3-methacryloxypropyl trimethoxysilane in the presence of benzoyl peroxide as an initiator agent by sol–gel process. The AISI 316L stainless steel (SS) was coated with this coating at ambient temperature. The effect of the hybrid coating on the adhesion promotion of bone cement to SS substrate was investigated qualitatively as well as quantitatively. The adhesion tests indicated that the coated 316L SS compared with the uncoated samples induces increases of ∼450% in strength and 200% in strain by single lap joint shear test. The samples were also characterised using scanning electron microscopy, optical microscopy, Fourier transform infrared spectroscopy and small angle X-ray scattering (SAXS). The test results indicated that the coated surfaces were quite uniform and crack free. Silicon mapping and SAXS analysis of the coated samples indicated that the inorganic moieties of the hybrid (i.e. Si–O–Si) were uniformly distributed and had a particle size distribution of ∼1·5 nm. In addition, the haemocompatibility of the coated sample was investigated by clotting time test. The result of clotting time for the coated 316L SS showed an increase of 74% compared with the uncoated samples.

A new metal–organic framework with high stability based on zirconium for sensing small molecules

A new porous Zr-based MOF was synthesized by the solvothermal method using 2,6-naphthalenedicarboxylic acid (NDC) as the organic linker, and its luminescent performance and stability were investigated systematically. The material synthesized exhibits quite high chemical stability in addition to exceptional high thermal stability, better than the existing luminescent MOFs. The experiments combining with computations indicate that the electron transfer from inorganic moieties to organic moieties contributes to the luminescent behavior of the Zr-NDC MOF besides the NDC ligand. As far as we know, this is the first study of investigating the luminescent behaviors of such Zr-based MOFs. Moreover, the cycling measurements demonstrate an interesting prospect for the long-term reusability of this material. The results obtained in this work may provide useful information for the design of physicochemically stable MOFs with permanent porosity in sensing applications in the future.

New halo(pseudohalo)cadmates templated by protonatated N-heterocyclic/diamine molecules

At ambient temperature, with various mono(di)protonated N-heterocyclic or diamine molecules as the cations, seven new halo(pseudohalo)cadmates [H2(bpee)][Cd(SCN)4] (bpee = 1,2-bis(4-pyridyl)ethene) 1, [H2(bpyp)][CdBr2(SCN)2] (bpyp = 1,2-bis(4-pyridyl)propane) 2, [H2(mbcha)][Cd3Br2(SCN)6] (mbcha = 4,4′-methylenebis(cyclohexylamine)) 3, [(Hdabco)2Cd3(SCN)8] (dabco = 1,4-diazabicyclo[2,2,2]octane) 4, [H2(bp)][Cd(SeCN)4] (bp = 4,4′-bipiperidine) 5 [H2(pdma)][Cd(SeCN)4]·2H2O (pdma = 1,4-phenylenedimethanamine) 6 and [H2(4,4′-dtdpy)][Cd2Br6] (dtdpy = dithioidipyridine) 7 were obtained. X-ray analysis revealed that (i) compound 1 possesses a three-dimensional (3D) supramolecular network structure with the one-dimensional (1D) channels, constructed from the inorganic [Cd(SCN)4]2− chains by weak S⋯S interactions. The H2(bpee)2+ molecules occupy the space of the channels; (ii) with H2(mbcha)2+ as the cation, the anion [Cd3Br2(SCN)6]2− of compound 3 exhibits a 1D ribbon structure, which can be described as a lengthways packing of planar bi-bridged trimers; (iii) compound 4 is the first example of the cation-controlled 3D thiocyanatocadmate with a composition [Cd3(SCN)8]2−; (iv) with H2(4,4′-dtdpy)2+ as the cation, the anion [Cd2Br6]2− of compound 7 also shows a 1D ribbon structure. This ribbon can be described as a transverse stacking of two planar bi-bridged single chains; (v) the ribbons of compounds 3 and 7 can be visualized as a slice of the two dimensional (2D) CdX2 layer; (vi) in compounds 2, 3, 5, 6 and 7, the organic molecules as the linkers extend the inorganic anionic moieties into various 2D supramolecular layer networks.

Altered characteristics of silica nanoparticles in bovine and human serum: the importance of nanomaterial characterization prior to its toxicological evaluation

BackgroundMany toxicological studies on silica nanoparticles (NPs) have been reported, however, the literature often shows various conclusions concerning the same material. This is mainly due to a lack of sufficient NPs characterization as synthesized as well as in operando. Many characteristics of NPs may be affected by the chemistry of their surroundings and the presence of inorganic and biological moieties. Consequently, understanding the behavior of NPs at the time of toxicological assay may play a crucial role in the interpretation of its results.The present study examines changes in properties of differently functionalized fluorescent 50 nm silica NPs in a variety of environments and assesses their ability to absorb proteins from cell culture medium containing either bovine or human serum.MethodsThe colloidal stability depending on surface functionalization of NPs, their concentration and time of exposure was investigated in water, standard biological buffers, and cell culture media by dynamic light scattering (DLS), zeta potential measurements and transmission electron microscopy (TEM). Interactions of the particles with biological media were investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) in bovine and human serum, and extracted proteins were assessed using matrix-assisted laser desorption/ionization-time of flight technique (MALDI-TOF).ResultsIt was recognized that all of the studied silica NPs tended to agglomerate after relatively short time in buffers and biological media. The agglomeration depended not only on the NPs functionalization but also on their concentration and the incubation time. Agglomeration was much diminished in a medium containing serum. The protein corona formation depended on time and functionalization of NP, and varied significantly in different types of serum.ConclusionsSurface charge, ionic strength and biological molecules alter the properties of silica NPs and potentially affect their biological effects. The NPs surface in bovine serum and in human serum varies significantly, and it changes with incubation time. Consequently, the human serum, rather than the animal serum, should be used while conducting in vitro or in vivo studies concerning humans. Moreover, there is a need to pre-incubate NPs in the serum to control the composition of the bio-nano-composite that would be present in the human body.

Self-assembly of polystyrene-block-poly(4-vinylpyridine) block copolymer on molecularly functionalized silicon substrates: fabrication of inorganic nanostructured etchmask for lithographic use

Block copolymers (BCPs) are seen as a possible cost effective complementary technique to traditional lithography currently used in the semiconductor industry. This unconventional approach has received increased attention in recent years as a process capable of facilitating the ever decreasing device size demanded. Control over microdomain orientation and enhancing long range order are key aspects for the utility of BCPs for future lithographic purposes. This paper provides an efficient route for the fabrication of highly ordered nanostructures suitable for such application. We investigate the significant effect of surface treatment regarding the self-assembly process of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) by employing an ethylene glycol layer, producing well defined perpendicular P4VP cylinders with long range order over large surface areas. Nanopores are generated through surface reconstruction using a preferential solvent, which allows for the incorporation of an inorganic moiety. Treatment of this pattern with UV/Ozone leads to formation of well-ordered iron oxide nanodots with a pitch of ∼26 nm. Furthermore, high aspect ratio silicon nanopillars result following pattern transfer (using Ar/O2).

Allosteric control in a metalloprotein dramatically alters function

Metalloproteins (MPs) comprise one-third of all known protein structures. This diverse set of proteins contain a plethora of unique inorganic moieties capable of performing chemistry that would otherwise be impossible using only the amino acids found in nature. Most of the well-studied MPs are generally viewed as being very rigid in structure, and it is widely thought that the properties of the metal centers are primarily determined by the small fraction of amino acids that make up the local environment. Here we examine both theoretically and experimentally whether distal regions can influence the metal center in the diabetes drug target mitoNEET. We demonstrate that a loop (L2) 20 Å away from the metal center exerts allosteric control over the cluster binding domain and regulates multiple properties of the metal center. Mutagenesis of L2 results in significant shifts in the redox potential of the [2Fe-2S] cluster and orders of magnitude effects on the rate of [2Fe-2S] cluster transfer to an apo-acceptor protein. These surprising effects occur in the absence of any structural changes. An examination of the native basin dynamics of the protein using all-atom simulations shows that twisting in L2 controls scissoring in the cluster binding domain and results in perturbations to one of the cluster-coordinating histidines. These allosteric effects are in agreement with previous folding simulations that predicted L2 could communicate with residues surrounding the metal center. Our findings suggest that long-range dynamical changes in the protein backbone can have a significant effect on the functional properties of MPs.

Adsorption and catalytic hydrolysis of carbaryl and atrazine on pig manure-derived biochars: Impact of structural properties of biochars

Biochars were produced from pig manure to elucidate the influence of biochars with high ash contents on the fate of pesticides. Adsorption and catalytic hydrolysis of carbaryl and atrazine on original biochars and deashed biochars were investigated. The two pesticides were substantially adsorbed by the biochars, with organic carbon normalized sorption coefficient (Koc) values of 102.65–103.66L/kg for carbaryl and 101.90–103.57L/kg for atrazine at Ce of 0.5mg/L. Hydrophobic effect alone could not explain the sorption, and several other processes including pore-filling and π–π electron donor–acceptor interactions were involved in pesticide adsorption. Adsorption increased greatly on the deashed biochar, indicating that some organic sorption sites in the original biochars were blocked or difficult to access due to their interactions with inorganic moiety. The pesticides were found to hydrolyze faster in the presence of biochars, and in the presence of biochar pyrolyzed at 700°C, carbaryl and atrazine were decomposed by 71.8% and 27.9% in 12h, respectively. The elevated solution pH was the main reason for the enhanced hydrolysis; however both the mineral surface and dissolved metal ions released from the biochars were confirmed to catalyze the hydrolysis.

Calixarenes: Versatile molecules as molecular sensors for ion recognition study

This article presents a brief account on designing of calixarene-based molecular sensor for recognition of various metal ions and anions and also different analytical techniques to monitor the recognition event. This review focuses only on calix[4]arene derivatives, in which mainly the lower rim is modified incorporating either crown moiety to make calix–crown hybrid ionophore to encapsulate metal ions or some fluoregenic inorganic and organic moieties to use it as signalling unit. In order to investigate effect of conformation of the calixarene unit and steric crowding on ion selectivity, designing of these molecules have been made using both the cone and 1,3-alternate conformations of the calixarene unit and also incorporating bulky ter-butyl group in few cases to impose controlled steric crowding. Among various ions, here focuses are mainly on biologically and commercially important alkali metal ion such as K + , toxic metal ions such as Hg2 + , Pb2 + , Cd2 + , important transition metal ion such as Cu2 + and toxic anion like F − . The techniques used to monitor the recognition event and also to determine binding constants with strongly interacting ions are fluorescence, UV-vis and 1H NMR spectroscopy. Most of the ionophores reported in this review have been characterized crystallographically, however no structural information (except one case) are incorporated in this article, as it will occupy space without significant enhancement of chemistry part. Different factors such as size of the ionophore cavity, size of metal ion, coordination sites/donor atoms, steric crowding and solvents, which determine selectivity have been discussed. Response of ion recognition process to different analytical techniques is another interesting factor discussed in this article. Ion-recognition property of a large variety of calix[4]arenes incorporating crown moiety to make hybrid ionophore, substituents to impose steric crowding and fluoregenic moieties as signalling unit has been reported. This report demonstrates how factors such as sizes of the ionophore and metal ions, donor atoms, steric crowding and solvents, influence ion-selectivity.

Soft Capsules, Hard Capsules, and Hybrid Capsules

Capsule structures are often regarded as mimics of living cells and have attracted attention within bio-related fields. In addition, their use in other practical applications has become important. The demands of practical applications have stimulated recent developments in capsule science and technologies. In this review, we focus on recent developments on the preparation and functionalization of capsule objects. In particular, we will summarize research on micro and nano-sized capsules prepared using supramolecular concepts and related strategies. The examples are classified into three categories. Molecular capsules such as calixarene, cavitands, and dendrimers are introduced together with dynamic molecular capsules at the air-water interface in the first part. In the second category, soft polymer capsules prepared by interfacial condensation, template synthesis, and emulsion synthesis are described and the unique contribution of layer-by-layer assemblies is emphasized. In the final part, various hard capsules composed of gold, carbon, silica, and other inorganic substances are described together with hybrid capsules made from inorganic components and organic moieties. In this section, construction of hierarchic structures of mesoporous capsules is highlighted.