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A glucose-sensitive multilayer shell, which was fabricated by the layer-by-layer (LbL) assembly method, can be used as a carrier for the encapsulation and controlled release of insulin. In the present report, glucose oxidase (GOD) and catalase (CAT) were assembled on insulin particles alternately via glutaraldehyde (GA) cross-linking. The resulting core-shell system has been proven to be glucose-sensitive. When the external glucose was introduced, the release ratio of insulin from the protein multilayer can be increased observably. This is likely attributed to the catalysis interaction of CAT/GOD shells to glucose, which leads to the production of H(+) and thus drops the pH of the microenvironment. Under the acidic conditions, on the one hand, a part of C=N bond formed from Schiff base reaction can be broken and thus increasing the permeability of the capsule wall. On the other hand, the solubility of insulin can also be increased. The above factors may be the key control to increase the release of insulin from the multilayer. Therefore, such CAT/GOD multilayer may have a great potential as a glucose-sensitive release carrier for insulin, and may open the way for the further application of LbL capsules in the drug delivery and controlled release, etc.

Combination of the layer-by-layer (LbL) technique with the porous template method has attracted significant interest as a versatile approach that has been used to prepare tubular nanomaterials with tailored properties. The process involves the sequential deposition of different species, such as polymers, nanoparticles, lipids, proteins, dyes and organic or inorganic small molecules into various porous templates, which are subsequently removed to yield free-standing nanotubes. At the same time, this approach permits the formation of composite nanotubes with the engineering features, including size, shape, composition and function. In this review, we summarize the synthesis and properties of various LbL-assembled composite nanotubes based on electrostatic attraction, hydrogen bonding, and covalent bonding. These assembled nanotubes possess potential application in biomedical fields such as bioseparations, biocatalysis, biosensor, and drug delivery.

An active biomimetic system by integrating kinesin motor, microtubule, and man-made biomimetic microcapsule has been constructed. Biomimetic microcapsules were fabricated by using the layer-by-layer technique and could serve as cargos in this active biomimetic system. Both of the hollow and filled capsules as cargos can be transported by kinesin motors along microtubules. It may help to create kinesin-powered complex hybrid micro- and nanodevices.

Supported lipid bilayers that mimic a cell membrane are well-defined model systems for fundamental research and also are critical for the development of new types of biosensor, biodevices and functional materials. We report here that supported lipid bilayers could spontaneously wrap around the layer-by-layer assembled luminescent nanotubes with a hydrophilic polymer-cushioned outer surface. We show that such one-dimensional lipid membranes are laterally mobile and have a high mobile fraction. We also used a simplified diffusion model to estimate the mobility of lipid molecules. These biointerfacing nanotubes have great potential for the design of novel biosensors and biomimetic functional nanomaterials.

Glucose oxidase (GOD) microcapsules held together by cross-linker, glutaraldehyde (GA), are fabricated by the layer-by-layer (LbL) assembly technique. The lipid bilayer containing CF(0)F(1)-ATPase was coated on the outer shell of GOD microcapsules. Driven under the proton gradients produced by catalysis of GOD microcapsules for glucose, ATP is synthesized from ADP and inorganic phosphate catalyzed by the ATPase rotary catalysis. The results show here that ATPase reconstituted on the GOD microcapsules retains its catalytic activity.

Over the past two decades, advances in modern biology and nanotechnology have enabled a rapid development in the design and building of biomimetic functional materials. ATP synthase is one of the most extensively studied molecular machines because it can be used as a rotary motor in the design of novel nanodevices and it can also continuously synthesize ATP in an artificial environment. A lot of research efforts have focused on assembling ATP synthase in biomimetic systems so that a complex cellular process can be constructed in a controllable manner. As we summarize here, layer-by-layer assembled microcapsules have proved to be a suitable cellular mimetic structure, which can be applied for engineering active biomimetic systems with a cellular process. An added benefit is that these assembled microcapsules can be used as bioenergy containers and thus ATP supply on demand.

Peptide-based self-assembling systems are increasingly attractive because of their wide range of applications in different fields. Peptide nanostructures are flexible with changes in the ambient conditions. Herein, a reversible shape transition between self-assembled dipeptide nanotubes (DPNTs) and vesicle-like structures is observed upon a change in the peptide concentration. SEM, TEM, AFM, and CD spectroscopy were used to follow this transition process. We show that dilution of a peptide-nanotube dispersion solution results in the formation of vesicle-like structures, which can then be reassembled into the nanotubes by concentrating the solution. A theoretical model describing this shape-transition phenomenon is presented to propose ways to engineer assembling molecules in order to devise other systems in which the morphology can be tuned on demand.

The assembled polyelectrolyte nanotubes composed of poly(styrenesulfonate) and poly(allylamine hydrochloride) multilayers by using the layer-by-layer assembly combined with the porous template method can be transformed into capsules by a high-temperature treatment. Scanning electron microscopy and confocal laser scanning microscopy images revealed the whole transition process. The structure transformation of polyelectrolyte multilayers after annealing can be initiated by the input of thermal energy which leads to a breakage of ion pairs between oppositely charged polyelectrolyte groups. The transition process from tubes to capsules is supposed to be driven by the Raleigh instability and leads to the generated polyelectrolyte capsules with different sizes.

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. Up to now, various nanostructures of MnO2, such as nanoparticles, [6] nanorods/-belts/-wires/-tubes/fibers, nanosheets, mesoporous/molecular sieves and branched structures, urchins/orchids, and other hierarchical structures 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, 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, polymer latex spheres and reducing metal nanoparticles, as well as “soft” ones, for example, emulsion droplets/ micelles and gas bubbles. 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 and Kirkendall effect. Recently, rhombododecahedral silver cages have been prepared by self-assembly coupled with the precursor crystal-templating approach. By treating the external morphologies of hollow structures, unique properties can be obtained. 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 MnO2 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 MnO2 nanostructures with controlled morphologies can be prepared by changing the morphologies of MnCO3 precursors, which can be simply obtained by adding the (NH4)2SO4 solution in the reaction system, and the

We report that a single dipeptide (l-Phe-l-Phe, FF), which is probably one of the smallest peptide gelators, can self-assemble into long nanofibrils in organic solvents and entangle further to form...

Brushing up: Poly(N‐isopropylacrylamide) micro‐ and nanostructures can be grown on a gold substrate by grafting the polymer brush from an initiator‐coated surface. The dependence of the brush height on the density of the initiator (controlled by the electron‐beam doses) allows spatially defined polymer patterns with varying heights and unique surface topographies (see image) to be created in a single step.

We report here that a synthesized multivalent cationic lipopeptide can be used for the delivery and release of gene assembled into lipopeptide vesicles. It is found experimentally that the synthesized lipopeptide is safe for gene therapy because of its biocompatibility and the innocuity of the hydrolysis products, such as lipids and amino acids. The experimental results also show that the assembled DNA/lipopeptide complex has high transfection efficiency in HeLa cells compared to that of the selected commercial reagent, which represents a novel vector for the delivery of therapeutic DNA.

Binary thermosensitive nanocomposites are fabricated by grafting block copolymers of poly(N-isopropylacrylamide) and poly(methoxy-oligo(ethylene glycol) methacrylate) onto gold nanoparticles through consecutive, surface-initiated, atom-transfer radical polymerization (ATRP). These Au@copolymer nanocomposites display a well-defined core/shell nanostructure and have two thermosensitive points near 33 and 55 °C in an aqueous suspension corresponding to the thermally induced conformational transition of inner homopolymer segments and outer oligo(ethylene glycol)-containing copolymer layer, respectively. Silver nanoparticles trapped within Au@copolymer nanocomposites with weakly crosslinked shells display thermally modulated catalytic activity as heterogeneous catalysts because of the thermosensitive collapse of the polymer layers.

We demonstrated that human serum albumin (HSA) patterns constructed in a solid substrate by using micro-contact printing (muCP) technique supported the deposition of phospholipid bilayer containing glycolipid, 10-tetradecyloxymethy-3,6,9,12-tetraoxahexacosyl 2-acetamido-2-deoxy-beta-D-glucopyranoside (PB1124). It is observed by confocal laser scanning microscopy (CLSM) that the obtained glycolipid patterns are well-defined, stable and can be used to recognize and immobilize Escherichia coli (E. coli). This strategy is promising to perform bacterial detection through solid surface recognition in a way of biosensors.

Hemoglobin (Hb) protein microcapsules held together by cross-linker, glutaraldehyde (GA), were successfully fabricated by covalent layer-by-layer (LbL) technique. The Schiff base reaction occurred on the colloid templates between the aldehyde groups of GA and free amino sites of Hb results in the formation of GA/Hb microcapsules after the removal of the templates. The structure of obtained monodisperse protein microcapsule was characterized by transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). The UV-Vis spectra measurements demonstrate the existence of Hb in the assembled capsules. Cyclic voltammetry (CV) and potential-controlled amperometric measurements (I-t curve) confirm that hemoglobin microcapsules after fabrication remain their heme electroactivity. Moreover, direct electron transfer process from protein to electrode surface was performed to detect the heme electrochemistry without using any mediator or promoter. The experiments of fluorescence recovery after photobleaching (FRAP) by CLSM demonstrate that the hemoglobin protein microcapsules have an improved permeability comparing to the conventional polyelectrolyte microcapsules.

Novel nanocomposites of gold nanoparticle and poly(4-vinylpyridine) (Au@PVP) were fabricated through surface-initiated atom-transfer radical polymerization (SI-ATRP) at ambient conditions. The citrate-stabilized gold nanoparticles were first modified by a disulfide initiator for ATRP initiation, and the following polymerization of 4-vinylpyridine (4VP) occurred on the surface of gold particles. The assembled Au@PVP nanocomposites are pH-responsive because of the pyridyl groups, which are facially protonated and positively charged. At low pH ( 3.2), the polymer chains shrink and wrap around the gold particle surface, which results in the aggregation of gold nanoparticles with a thin shrunken polymer layer under TEM observation. Such assembled A...

Biological organic-inorganic hybrid materials often achieve excellent properties and provide inspiration for the design of advanced materials. The organic phase plays a key role in determining the properties of biogenic materials, and the spatial arrangement of organic and inorganic phases provides direct evidence for interaction between the two phases. Super-resolution fluorescence microscopy was used to visualize the gelatin distribution in two different crystalline polymorphs of calcium carbonate (vaterite and calcite) and to investigate the process by which gelatin is excluded from the crystals. The results demonstrated that gelatin is distributed through vaterite microspheres in the form of nanoparticles, whereas it tends to accumulate on the edges of the calcite rhombohedra.

Multilayer film coated CaCO3 microspheres were employed as pH responsive ATP carriers to drive kinesin movement. The production of oxygen scavengers in a kinesin-microtubule system induces the decomposition of ATP-loaded CaCO3 microspheres and then leads to the release of ATP.

Photothermal therapy based on gold nanostructures has been widely investigated as a state-of-the-art noninvasive therapy approach. Because single nanoparticles cannot harvest sufficient energy, self-assemblies of small plasmonic particles into large aggregates are required for enhanced photothermal performance. Self-assembled gold nanorods in lipid bilayer-modified microcapsules are shown to localize at tumor sites, generate vapor bubbles under near-infrared light exposure, and subsequently damage tumor tissues. The polyelectrolyte multilayer enables dense packing of gold nanorods during the assembly process, which leads to the formation of vapor bubbles around the excited capsules. The resulting vapor bubbles achieve a high efficiency of suppressing tumor growth compared to single gold nanorods. In vivo experiments demonstrated the ability of soft-polymer multilayer microcapsules to cross the biological barriers of the body and localize at target tissues.

We report an environmentally-responsible limited hydrothermal reaction to construct gram-scale MnO

A new type of biohybrid photo-electrochemical cell was fabricated by layer-by-layer assembly of photosystem II and reduced graphene oxide. We demonstrate that the photocurrent in the direct electron transfer is enhanced about two fold with improved stability. The assembly strategy without any cross-linker or additional electron mediators makes the cell fabrication and operation much simpler as compared to previous approaches. This work may open new routes for the construction of solar energy conversion systems based on photoactive proteins and graphene materials.

The controlled self-assembly of diphenylalanine (FF) into unilocular and multilocular hollow spheres was successfully achieved by an ultrasound-assisted emulsion droplet template method. This novel surfactant-free emulsion droplet template method is envisaged to be applicable to other biomolecules and materials.

Diphenylalanine (FF) microrods were obtained by manipulating the fabrication conditions. Fourier transform infrared (FTIR), circular dichroism (CD), fluorescence (FL) spectroscopy, and X-ray diffraction (XRD) measurements revealed the molecular arrangement within the FF microrods, demonstrating similar secondary structure and molecular arrangement within FF microtubes and nanofibers. Accordingly, a possible mechanism was proposed, which may provide important guidance on the design and assembly manipulation of peptides and other biomolecules. Furthermore, characterization of a single FF microrod indicates that the FF microrod can act as an active optical waveguide material, allowing locally excited photoluminescence to propagate along the length of the microrod with coupling out at the microrod tips.

We report the preparation of copolymer, poly(N-isopropylacrylamide)-co-(N,N'-methylenebisacrylamide) (PNIPAM-co-MBAA) nanotubes with different composite ratios through surface-initiated atom transfer radical polymerization using a porous anodic aluminum oxide membrane as a template. It is found that the tubular wall strongly depends on the monomer concentration. The composite-induced changes in dimension and shape of nanotubes, especially the wall thickness, were studied by scanning electron microscopy, transmission electron microscopy, atom force microscopy, FT-IR, and gel permeation chromatography. The PNIPAM-co-MBAA nanotubes exhibit a high flexibility and stability.

Nanotubes of Polyethyleneimine (PEI) and Poly(styrene-alt-maleic anhydride) (PSMA) based on the layer-by-layer (LbL) technique and template method through covalent bond have been fabricated. The combination of LbL assembly and the template method can well control the length, wall thickness, outside, and inner diameters of the resulting nanotubes. The formation of covalent between PEI and PSMA enables the nanotubes with a good mechanical stability. The uniform tubular structure has been characterized by scanning electron microscopy (SEM) and transmission Electron Microscopy (TEM). Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) measurements confirms the formation of covalent bond in the assembled nanotubes.

Nanotubes of poly(4-vinylpyridine) (PVP) and poly(acrylic acid) (PAA) were fabricated by hydrogen bonding based on layer-by-layer (LbL) assembly. The uniform and flexible tubular structures were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). FTIR and X-ray photoelectron spectroscopy (XPS) measurements confirm the formation of hydrogen bonds in the assembled nanotubes. PAA can be released from the assembled PAA/PVP nanotubes in a basic aqueous solution to give the walls of the tubes a porous structure. Such assembled nanotubes can be considered as carriers for catalysts or drugs, especially in aqueous solution against capillary force.

The Langmuir monolayer properties of lower rim aromatically substituted calix[4]arenes, 5,11,17,23-tetra-tert-butyl-25,27-bis(2-naphth-1′-ylacetylaminoethoxy)-26,28-dihydroxylcalix[4]arene (BNAEC), 5,11,17,23-tetra-tert-butyl-25,27-bis(2-benzoylamino ethoxy)-26,28-dihydroxylcalix[4]arene (BBAEC) and 5,11,17,23-tetra-tert-butyl-25,27-bis(2-cinnamoylaminoethoxy)-26,28-dihydroxylcalix[4]arene (BCAEC), have been studied. Film balance measurements and Brewster angle microscopy (BAM) observation demonstrate that all the compounds can form Langmuir monolayers with different molecular limiting areas. BNAEC or BBAEC monolayer is able to form condensed domains during compression, while BCAEC monolayer can never form condensed domain. BNAEC monolayer is more readily to form condensed domain than BBAEC monolayer. Moreover, BNAEC monolayer can form the total condensed phase during compression even when T=28 °C, while BBAEC monolayer can not when T>10 °C. The results imply that different lower rim aromatic substitutions affect essentially the intermolecular interaction and molecular packing in the monolayer at air/water interface.

The permeability of lipid and protein microcapsules fabricated by alternating adsorption of human serum albumin (HSA) and L-alpha-dimyristoylphosphatidic acid (DMPA) on a template and subsequent removal of the core is studied as a function of pH value and supplementary layers. The capsules were permeable for macromolecules (FITC-labeled dextran, M(w) 40 kDa) at pH4.8 and impermeable at pH7.4. The assembly of supplementary DMPA bilayers rendered the capsules impermeable for small hydrophilic molecules such as 6-carboxyfluorescein (6-CF). Hence DMPA/HSA capsules can be resealed after fabrication by supplementary layers. This provides the opportunity of applying such biomimetic membrane capsules as drug carriers or model systems to study biological processes at membranes.

Single molecule localization based super-resolution fluorescence microscopy offers significantly higher spatial resolution than predicted by Abbe’s resolution limit for far field optical microscopy. Such super-resolution images are reconstructed from wide-field or total internal reflection single molecule fluorescence recordings. Discrimination between emission of single fluorescent molecules and background noise fluctuations remains a great challenge in current data analysis. Here we present a real-time and robust single molecule identification and localization algorithm, SNSMIL (Shot Noise based Single Molecule Identification and Localization). This algorithm is based on the intrinsic nature of noise, i.e., its Poisson or shot noise characteristics and a new identification criterion, QSNSMIL, is defined. SNSMIL improves the identification accuracy of single fluorescent molecules in experimental or simulated datasets with high and inhomogeneous background. The implementation of SNSMIL relies on a graphics processing unit (GPU), making real-time analysis feasible as shown for real experimental and simulated datasets.

Conductive nanotubes were fabricated by the alternate adsorption of negatively charged polypyrrole (PPy) and positively charged poly(allylamine hydrochloride) (PAH) onto the inner pores of polycarbonate templates. Nanotubes are obtained by the subsequently removal of the template. Using several microscopic and spectroscopic techniques, we demonstrate that the yielded materials posses a tubular structure and conductive properties. The conductivity of PPy/PAH nanotubes is measured as 0.008 S cm -1 .

Thermosensitive polymer nanotubes can be fabricated within an aminopropylsilane-modified porous anodic aluminum oxide membrane by surface-initiated atom transfer radical polymerization (ATRP) followed by template removal. DSC experiments prove that the synthesized PNIPAM-co-MBAA copolymer nanotubes have a reversible thermosensitive behavior. The temperature-induced changes in dimension and shape of the nanotubes were studied by AFM in real time in an aqueous environment. It indicates that the nanotubes undergo a shape alteration from an ellipse to circular shape in water upon heating to LCST or above.

The dynamic adsorption and penetration characteristics of β-lactoglobulin into the monolayer of two different chain-length phosphatidylcholines (DSPC, DPPC) are systematically investigated using Brewster angle microscopy (BAM), fluorescence microscopy (FM) and film balance technique. It was found that all the two phosphatidylcholines can form stable complex films with the β-lactoglobulin. In the complex system of DPPC or DSPC/β-lactoglobulin the lipid domains were observed again owing to the penetration of the protein. With the increase of surface pressure, the stripe and block domains appeared and gradually turned brighter. It has been considered that protein is squeezed out from the lipid monolayer and aggregated at interface. The critical surface pressure of the β-lactoglobulin separated from DPPC or DSPC phase is increased when lipid has longer alkyl chain length. Therefore, the hydrophobic effect can be considered as a main factor to lead to the formation of a stabilized mixed lipid/protein film.

We demonstrated that phospholipid ( l -α-dipalmitoylphosphatidylcholine, DPPC)-capped gold nanoparticles could be synthesized with one step by reduction of HAuCl4 in aqueous solution using sodium citrate and simultaneously accompanying with the phase transition across the water/toluene interface into the organic phase. Such a transition process has been observed by the color changes and verified by the UV–visual adsorption. Transition electron microcopy (TEM) image shows that the one-step synthesized gold nanoparticles obtained in the toluene phase has approximately 10 nm. Fourier transfer infrared reflectivity (FT-IR) study on the lipid-capped particles demonstrates that DPPC has adsorbed onto the gold nanoparticle surface. Extention of this work to other metals with even smaller sizes and use of different lipids would be possible.

Biogenic microcapsules comprised of l-α-dimyristoyl phosphatitic acid (DMPA)/human serum albumin (HSA) were prepared by stepwise adsorption of DMPA/HSA multilayers onto charged colloids and subsequent dissolution of the colloidal cores. The properties of both lipid/protein modified particles and the hollow capsules were characterized by microelectrophoresis, scanning electron microscopy, transmission electron microscopy, confocal laser scanning microscopy, and scanning force microscopy, respectively. Single particle light scattering together with small-angle X-ray scattering measurements revealed that DMPA forms a bilayer structure on the HSA surface. A combination of HSA and DMPA on hollow capsules is proposed as a biomimetic membrane model.

Gold nanoparticles synthesized in aqueous phase were modified by thioglycolic acid (TGA) and then capped with cetyltrimethyl ammonium bromide (C16TAB), myristyltrimethyl ammonium bromide (C14TAB), and dodecyltrimethyl ammonium bromide (C12TAB), respectively. The surfactant capped nanoparticles could be transferred into toluene without aggregation across the water/toluene interface under vigorous stirring. The transfer process was certified by the rapid change of color of the aqueous and organic phase, zeta potential of nanoparticles, and UV–vis absorbance spectroscopy. Experimentally, it is found that only decyltrimethyl ammonium bromide (C10TAB) capped nanoparticles were unable to ensure the phase transfer in the organic phase. Both transmission electron microscopy (TEM) images and static light scattering measurement demonstrated the narrow size distribution of the capped nanoparticles in toluene.

The influence of two indole inhibitors on the hydrolysis reaction of l-dipalmitoylphosphatidylcholine (l-DPPC) catalyzed by phospholipase A2 (PLA2) has been studied in the coexistence region using surface pressure as function of time (π–t) and Brewster angle microscopy (BAM) measurements. Similar experiments have been performed with l-DPPC vesicles made by ultrasonication method using transmission electron microscopy (TEM). Comparing the π–t curves and BAM images, which show defected domains after a certain reaction time, as well as TEM images of defected vesicles, one can conclude that the two indole inhibitors have different abilities in reducing the activity of PLA2. The described experiments show that BAM and TEM can be successfully used to study the influence of newly designed inhibitors on the hydrolysis reaction catalyzed by PLA2.

AOT containing water-in-oil (W/O) microemulsion was used as an organized reaction environment for silica preparation originating from hydrolysis and crosslink of tetraethoxysilane (TEOS). The nucleation and growth of skeletal silica shperes with a diameter of 40 μm were synthesized in association with microemulsion. Study on the structure and morphology, principally by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), indicates that the final product is subject to the composition of microemulsion and aging time. A possible mechanism involving collision and fusion among large quantities of droplets covered by surfactant molecules was proposed here, attempting to describe the growth of the network structured silica spheres.

The hydrolysis reaction of L-alpha-distearoylphosphatidylcholine (DSPC) monolayers catalyzed by phospholipase A2 (PLA(2)) has been studied using polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) with film balance measurements. The PM-IRRAS analysis provides quantitative information about the reaction efficiency at different surface pressures. It was found that the reaction efficiency of L-DSPC monolayer hydrolysis catalyzed by PLA(2) decreased with increasing surface pressure. At zero pressure (lift-off point), the hydrolysis reaction efficiency has the highest value of 45%. Increasing surface pressure leads to the decrease of the hydrolysis efficiency. Since the surface pressure is above 20 mN/m, the hydrolysis reaction nearly stopped. PM-IRRAS technique provides a powerful means to study the hydrolysis process catalyzed by phospholipase A2 at the air/water interface.

Monolayers of newly synthesized amide phospholipids, 1-O-hexadecyl-2-N-palmitoyl-2-amino-2-deoxy-sn-glycero-3-phosphocholine (l-ether-amide-PC) and 1-palmitoyl-2-N-palmitoyl-2-amino-2-deoxy-sn-glycero-3-phosphocholine (l-ester-amide-PC) were investigated at the air/subphase interface by Brewster angle microscopy combined with a conventional LB trough and Grazing incidence X-ray diffraction (GIXD). Both systems investigated exhibit two-dimensional domains with characteristic shape in the coexistence region between liquid-expanded (LE) and liquid-condensed (LC) phases. Especially l-ether-amide-PC shows highly chiral domains depending on temperature. The largest chiral domains (400 μm) growing in a clockwise direction are obtained at 25 °C. Such large domains have rarely been observed for phospholipids before. Thermodynamic data derived from π−A isotherms provide information about critical temperature (Tc) and phase transition enthalpy (ΔH) for both amide phospholipids. The amide group leads to pronounced di...

Hollow capsules have been prepared by electrostatic layer-by-layer self-assembly of tetrasulfophthalocyanine iron [Fe(PcS4)] in alternation with poly(diallyldimethylammonium chloride) (PDDA) onto the precursor shells with well-defined internal volumes. The resultant linear deposition process was monitored by UV/Vis absorption spectra, microelectrophoresis, and scanning force microscopy (SFM). The formation of intact spherical capsules was verified by confocal laser scanning microscopy and SFM. A mean density of ca. 3 [Fe(PcS4)] molecules per nm2 and a wall thickness of 2.7 ± 0.2 nm for each PDDA/[Fe(PcS4)] bilayer were obtained. The characteristic maximum absorption of [Fe(PcS4)] in the coating suggests that [Fe(PcS4)] exists mainly in the form of an aquo complex [HOFeIII(PcS4)]. The fabricated hollow capsules display a high stability in response to light irradiation and high temperature.

The hydrolysis reaction of L-R-dipalmitoylphosphatidylcholine (L-DPPC) catalyzed by cabbage phospholipase D (PLD) at the air/water interface has been studied by Brewster angle microscopy (BAM) and film balance technique. The curves of surface pressure versus time show that the hydrolysis reaction depends on the initial state of the lipid monolayer. The BAM images display that the hydrolysis reaction preferentially occurs in the liquid-expanded phase where PLD has a maximum activity. In the coexistence region of liquid-expanded and liquid-condensed phases, a “lotus-like” domain of the monolayer was observed, indicating that the hydrolysis product 1, 2-dipalmitoylphosphatidic acid (DPPA) created a new phase, which inhibited the reaction rate of hydrolysis.

Wormlike mesoporous silica is prepared by using a complex template: mixed poly(styrenesulfonate sodium) and cetyltrimethylammonium bromide. Such a pore modification with polyelectrolyte under the control of a sol−gel process can be used as an efficient route in fabricating highly flexible and ordered mesoporous silica materials.