Porous carbohydrate-based materials via hard templating.

Among various techniques, the hydrothermal carbonization (HTC) of biomass (either isolated carbohydrates or crude plants) is a promising candidate for the synthesis of novel carbon-based materials with a wide variety of potential applications. In this Minireview, we discuss various synthetic routes towards such porous carbon-based materials or composites through the HTC process, using the nanocasting procedure. We focus on the synthesis of carbon materials with different pore systems and morphologies directed by the presence of various nanostructured inorganic sacrificial templates.

Core-shell particle interconversion with di-stimuli-responsive diblock copolymers.

Core-shell reversible particle precipitation from aqueous di-stimuli-responsive diblocks is demonstrated as also is the interconversion from one core-shell combination to the other.

Thermo-responsive columns for HPLC: The effect of chromatographic support and polymer molecular weight on the performance of the columns.

Recently a novel technique has been developed in chromatography, namely thermo-responsive chromatography. This employs the use of thermo-responsive polymers grafted onto pre-formed stationary phases for the separation of hydrophobic analytes. The resultant thermo-responsive silica exhibits temperature-controlled hydrophilic-hydrophobic properties.

The fusion of membranes and vesicles: pathway and energy barriers from dissipative particle dynamics.

The fusion of lipid bilayers is studied with dissipative particle dynamics simulations. First, to achieve control over membrane properties, the effects of individual simulation parameters are studied and optimized. Then, a large number of fusion events for a vesicle and a planar bilayer are simulated using the optimized parameter set.

Near-IR remote release from assemblies of liposomes and nanoparticles.

Set free by light: Near-IR (NIR) laser-initiated remote release of fluorescent dye from complexes of liposome-gold-nanoparticle aggregates is demonstrated (see fluorescence images). Complexes of the desired size are shown to be a viable approach to the construction of vesicle-based drug-delivery systems with light-triggered remote release characteristics. This opens up a new method to manipulate liposome-based drug-delivery systems in a biocompatible way by using the near-IR spectral range.

Hydrothermal carbon spheres containing silicon nanoparticles: synthesis and lithium storage performance.

Spherically shaped carbon/silicon nanocomposites have been obtained in a one-step procedure using hydrothermal carbonization of glucose in the presence of commercially available silicon nanoparticles and have been tested electrochemically as an anode material for lithium-ion batteries.

Thermo-responsive monolithic materials.

One of the recent major improvements of HPLC was the introduction of monolithic silica columns, which have the advantage of faster separation and lower back pressure as compared to common silica beads. Here, we present an interesting alternative to such reversed-phase monolithic columns by a convenient coupling route of a thermo-responsive polymer to hydrophilic silica monoliths. Poly(N-isopropylacrylamide) (PNIPAM) was polymerized in solution via a reversible addition fragmentation chain transfer (RAFT) polymerization technique and coupled then in situ onto an amino-modified silica monolithic column.

Composite multilayered biocompatible polyelectrolyte films with intact liposomes: stability and temperature triggered dye release.

The design of new quasi-2D biocompatible films able to release a drug in a controlled manner through the application of physical stimuli is of outstanding interest in biomaterials science. Herein, construction of composite nanofilms with multiple strata of stabilized large unilamellar liposomes is developed. The film has a multilayered architecture formed by the layer-by-layer (LbL) technique utilising two biocompatible polyelectrolytes, hyaluronic acid and poly-l-lysine (HA and PLL), onto which phospholipid liposome "interlayers" are adsorbed and subsequently embedded by further polyelectrolyte adsorption.

Growth of osteoblast-like cells on biomimetic apatite-coated chitosan scaffolds.

Porous scaffold materials that can provide a framework for the cells to adhere, proliferate, and create extracellular matrix are considered to be suitable materials for bone regeneration. Interconnected porous chitosan scaffolds were prepared by freeze-drying method, and were mineralized by calcium and phosphate solution by double-diffusion method to form nanoapatite in chitosan matrix. The mineralized chitosan scaffold contains hydroxyapatite nanocrystals on the surface and also within the pore channels of the scaffold.

Three-dimensional growth behavior of osteoblasts on biomimetic hydroxylapatite scaffolds.

The authors used rapid prototyping to produce three-dimensional hydroxylapatite scaffolds with controlled, fully interconnected porosity. The purpose of this study was to illuminate the effect of hormones on the osteogenic differentiation and to investigate how osteoblasts colonize the three-dimensional scaffold focusing on the formation of the cellular network. Preosteoblasts were seeded onto scaffolds, were optionally treated with the osteogenic hormones triiodo-L-thyronine (T3) and 1,25-dihydroxyvitamin-D3 (D3), and the expression of osteoblastic marker genes was investigated.

Fabrication of hollow multifunctional spheres containing MCM-41 nanoparticles and magnetite nanoparticles using layer-by-layer method.

Macroscopic mesoporous silica spheres have been fabricated by alternatively depositing preformed MCM-41 nanoparticles and polyelectrolytes onto polystyrene lattices. High surface area hollow mesoporous spheres were obtained by removal of the core by solvent or calcination. Further, the versatility of the layer-by-layer (LBL) method was extended to fabricate magnetite-mesoporous silica composites by depositing magnetite and MCM-41 nanoparticles onto polystyrene beads.

Structure formation and fractionation in systems of polydisperse attractive rods.

Fractionation effects and the formation of structured domains are investigated in polydisperse systems of attractive spherocylinders with the help of Monte Carlo simulations. For sufficiently high attractive interaction strength and pressure, the large rods in the system aggregate and form a highly ordered hexatic monolayer that coexists with an isotropic fluid of smaller rods. Fractionation diminishes with decreasing interaction strength but is still observed for hard rod systems, in which the large rods form a nematic droplet rather than a monolayer.

Adhesion of polyelectrolyte microcapsules through biotin-streptavidin specific interaction.

Adhesion of PAH/PSS and PDADMAC/PSS capsules through electrostatic and specific interactions has been investigated using reflective interference contrast microscopy (RICM). Adhesion of capsules via electrostatic interactions was found to be spontaneous and strong. Capsules functionalized with poly(l-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) did not exhibit significant adhesion (as determined by the adhesion area) to streptavidin-coated substrates, whereas capsules functionalized with biotinylated PLL-g-PEG showed a significantly larger adhesion area.

Biomimetic mineral-organic composite scaffolds with controlled internal architecture.

Bone and cartilage generation by three-dimensional scaffolds is one of the promising techniques in tissue engineering. One approach is to generate histologically and functionally normal tissue by delivering healthy cells in biocompatible scaffolds. These scaffolds provide the necessary support for cells to proliferate and maintain their differentiated function, and their architecture defines the ultimate shape.

Farnesol and geranylgeraniol modulate the structural properties of phosphatidylethanolamine model membranes.

The biological activity of farnesol (FN) and geranylgeraniol (GG) and their isoprenyl groups is related to membrane-associated processes. We have studied the interactions of FN and GG with 1,2-dielaidoyl-sn-glycero-3-phosphoethanolamine (DEPE) membranes using DSC and X-ray diffraction. Storage of samples at low temperature for a long time favors a multidomain system formed by a lamellar crystalline (Lc) phase and isoprenoids (ISPs) aggregates.

Salt softening of polyelectrolyte multilayer capsules.

The changes in the morphology and the mechanical properties of hollow polyelectrolyte multilayer capsules made from poly(styrenesulfonate)/poly(allylamine hydrochloride) in response to added salt were investigated. We found that capsules shrink in response to salt exposure. The effect depends strongly on the nature of the salt added and follows trends of the Hoffmeister series, with weakly hydrated cations inducing the strongest shrinking.

Oscillations in solvent fraction of polyelectrolyte multilayers driven by the charge of the terminating layer.

We have investigated polyelectrolyte multilayers of poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) in contact with D2O by neutron reflectometry. The study particularly focuses on the changes in the solvent fraction of the system upon addition of a layer. When the layers are deposited at a low salt concentration (0.

Effects of oleic acid and its congeners, elaidic and stearic acids, on the structural properties of phosphatidylethanolamine membranes.

Fatty acid derivatives are abundant in biological membranes, mainly as components of phospholipids and cholesterol esters. Their presence, free or bound to phospholipids, modulates the lipid membrane behavior. The present study shows the differential influence of the C-18 fatty acids (FAs), oleic, elaidic, and stearic acids on the structural properties of phosphatidylethanolamine (PE).

Change and stabilization of the amyloid-beta(1-40) secondary structure by fluorocompounds.

The misfolding of the amyloid peptide, which is the result of a well-known alpha-to-beta transition, causes neurodegenerative disorder. Fluorinated alcohols have been described in the literature as potent solvents which can refold the beta-conformation. The present studies demonstrate the effectiveness of differently fluorinated alcohols for the beta-to-alpha refolding process on fibrillar aggregated amyloid beta(1-40).

Diversity patterns from ecological models at dynamical equilibrium.

We study a dynamic model of ecosystems where an immigration flux assembles the species community and maintains its biodiversity. This framework is particularly relevant for insular ecosystems. Population dynamics is represented either as an individual-based model or as a set of deterministic equations for population abundances.