On the design and development of foamed GO-hydrogel nanocomposite surfaces by ultra-short laser processing.

Graphene oxide (GO) and reduced graphene oxide have outstanding qualities that could be exploited as reinforcement and antibacterial agents in a plethora of biomedical applications. In this contribution, it is reported the deployment of a polyacrylamide GO-hydrogel composite (GO@pAAm) which was photo-converted and structured by ultra-short laser irradiation using a direct laser writing (DLW) approach. The materials were characterized by Fourier Transform Infrared spectroscopy, scanning electron microscopy and confocal microscopy.

Mechanochemical Synthesis of Polyanilines and Their Nanocomposites: A Critical Review.

The mechanochemical synthesis of polyanilines (PANIs), made by oxidative polymerization of anilines, is reviewed. First, previous knowledge of the polymerization reaction in solution is discussed to understand the effect of different parameters: oxidant/monomer ratio, added acid, oxidant, temperature and water content on the properties of the conducting polymers (molecular weight, degradation, doping/oxidation level, conductivity, and nanostructure). The work on mechanochemical polymerization (MCP) of anilines is analyzed in view of previous data in solution, and published data are critically reconsidered to clarify the interpretation of experimental results.

Development of micropatterning polyimide films for enhanced antifouling and antibacterial properties.

A commercial biomedical Polyimide (PI) film was topographically and chemically modified by generating micrometric periodic arrays of lines using Direct Laser Interference Patterning (DLIP) in order to improve antifouling and antibacterial properties. DLIP patterning was performed with periods from 1 μm to 10 μm. The physical modification of the surface was characterized by SEM, AFM and contact angle measurements and, the chemical composition of the ablated surfaces was analyzed by ATR-IR and XPS spectroscopies.

Improving the retention and reusability of Alpha-amylase by immobilization in nanoporous polyacrylamide-graphene oxide nanocomposites.

Alpha-amylase was immobilized inside three different polymeric matrices: polyacrylamide hydrogel (PAAm), polyacrylamide-graphene oxide nanocomposite (PAAm-GO) and alginate in order to study and compare the effect of the matrix on the catalytic performance. The morphology, swelling, mechanical properties, retention efficiency, and the catalytic behavior of these newly supported biocatalysts were studied. Nanocomposite made of PAAm-GO matrix incorporated 98% of the enzyme, likely through a cooperative effect, while alginate gels incorporated only 30%.

Photothermally enhanced bactericidal activity by the combined effect of NIR laser and unmodified graphene oxide against Pseudomonas aeruginosa.

The manuscript shows the application of unmodified graphene oxide (GO) as a photothermally susceptible material to trigger antibacterial effects. The synthesis and characterization of unmodified GO easily dispersed in aqueous solutions is also shown. High GO concentrations in the dark and low GO concentrations irradiated with near infrared light (NIR) produced death in nosocomial bacterium (Pseudomonas aeruginosa).

Nanocomposites based on pH-sensitive hydrogels and chitosan decorated carbon nanotubes with antibacterial properties.

The present work aimed to study the properties of a novel nanocomposite with promising biomedical applications. Nanocomposites were prepared by the addition of different concentrations of chitosan decorated carbon nanotubes to acrylamide-co-acrylic acid hydrogels. The nanocomposites chemical structure was characterized by Fourier Transform Infrared Spectroscopy (FT-IR).

Templated CaCO3 Crystallization by Submicrometer and Nanosized Fibers.

Electrospun submicrometer-sized poly(ε-caprolactone) (PCL) meshes and nanosized multiwalled carbon nanotubes (MWCNTs) were used as a template for preparing porous and interconnected inorganic-organic hybrid materials composed of CaCO3. Herein, we describe the proportion and incorporation method of submicrometer-sized plasma-treated PCL meshes over areas >1 mm(2) with CaCO3 using three crystallization methods including the use of poly(acrylic acid) (PAA). We found that flexible and rigid acid-functionalized MWCNTs showed a clear capacity and effects to penetrate calcite particles.

Biosorption of aluminum through the use of non-viable biomass of Pseudomonas putida.

Living and non-living biomass of Pseudomonas putida A (ATCC 12633) was used as biosorbent for the removing of Al(3+) from aqueous solutions. The process was stable with time, efficient at pH 4.3 and between 15°C and 42°C.

Bioethanol production by reusable Saccharomyces cerevisiae immobilized in a macroporous monolithic hydrogel matrices.

Performance of yeasts on industrial processes can be dramatically improved by immobilization of the biocatalyst. The immobilization of Saccharomyces cerevisiae inside monolithic macroporous hydrogels were produced by in-situ polymerization of acrylamide around a live yeast suspension under cryogelation conditions. Preculture of the yeasts was not necessary and this innovative and simple procedure is amenable to scaling-up to industrial production.

IgY against enterotoxigenic Escherichia coli administered by hydrogel-carbon nanotubes composites to prevent neonatal diarrhoea in experimentally challenged piglets.

In previous studies, the applicability of polymeric hydrogels for the protection of egg yolk immunoglobulin (IgY) against simulated gastric conditions was established. Thereafter, the performance of the hydrogels was improved with the addition of chitosan wrapped carbon nanotubes and the in vitro toxicity for porcine intestinal cells of these nanocomposites was assessed. The objective of the present study was to evaluate in vivo the protective efficacy of the nanocomoposite matrix for IgY when the immunoglobulin is used against enterotoxigenic Escherichia coli (ETEC) in challenged piglets.

Cysteine modified polyaniline films improve biocompatibility for two cell lines.

This work focuses on one of the most exciting application areas of conjugated conducting polymers, which is cell culture and tissue engineering. To improve the biocompatibility of conducting polymers we present an easy method that involves the modification of the polymer backbone using l-cysteine. In this publication, we show the synthesis of polyaniline (PANI) films supported onto Polyethylene terephthalate (PET) films, and modified using cysteine (PANI-Cys) in order to generate a biocompatible substrate for cell culture.

Electroanalysis using modified hierarchical nanoporous carbon materials.

The role of the electrode nanoporosity in electroanalytical processes is discussed and specific phenomena (slow double layer charging, local pH effects) which can be present in porous electrode are described. Hierarchical porous carbon (HPC) materials are synthesized using a hard template method. The three dimensional carbon porosity is examined using scanning electron microscopy on flat surfaces cut using a focused ion beam (FIB-SEM).

A direct and quantitative three-dimensional reconstruction of the internal structure of disordered mesoporous carbon with tailored pore size.

A new technique that allows direct three-dimensional (3D) investigations of mesopores in carbon materials and quantitative characterization of their physical properties is reported. Focused ion beam nanotomography (FIB-nt) is performed by a serial sectioning procedure with a dual beam FIB-scanning electron microscopy instrument. Mesoporous carbons (MPCs) with tailored mesopore size are produced by carbonization of resorcinol-formaldehyde gels in the presence of a cationic surfactant as a pore stabilizer.

Fabrication of highly ordered arrays of platinum nanoparticles using direct laser interference patterning.

Highly ordered electrode arrays composed of lines of platinum nanoparticles deposited onto gold substrates have been made by direct laser interference patterning of polyaniline thin films, followed by electrochemical deposition of platinum nanoparticles. Nanostructured arrays of electrocatalytic platinum particles are built in that way.

Easy way to fabricate nanostructures on a reactive polymer surface.

The fabrication of advanced architectures in poly(glycidylmethacrylate-co-styrene) (PGMA-S) copolymers using direct laser interference patterning (DLIP) and its selective functionalization is reported. The structure features depend mainly on the laser energy used and on the styrene content in the copolymer. The topography, measured by electronic scanning microscopy, show regular and ordered arrays for the polystyrene (PS) and for the copolymers PGMA-S.

Large area fabrication of tuned polystyrene/poly(methylmethacrylate) periodic structures using laser interference patterning.

The fabrication of advanced architectures in poly(methylmethacrylate-co-styrene) (PMMA-S) copolymers (ranging from 12 to 66% mol content of methylmethacrylate) using direct laser interference patterning is reported. For all copolymer compositions, two different regimes were observed. At low laser intensities, the irradiated surfaces swell up due to the formation of microbubbles that result from the degradation of the methylmetacrylate (MMA) component.

Influence of conducting polymers based on carboxylated polyaniline on in vitro CaCO3 crystallization.

Conducting polymers are interesting materials of technological applications, while the use of polymers as additives controlling crystal nucleation and growth is a fast growing research field. In the present article, we make a first step in combining both topics and report the effect of conducting polymer derivatives, which are based on carboxylated polyanilines (c-PANIs), on in vitro CaCO3 crystallization by the Kitano and gas diffusion method. This is the first example of the mineralization control of CaCO3 by a rigid carboxylated polymer.

Functionalised conjugated materials as building blocks of electronic nanostructures.

Two different approaches towards conjugated material (carbon nanotubes, conjugated polymers) functionalisation are presented: covalent bonding of functional groups and covalent interaction with soluble polymers. Covalent functionalisation of carbon nanotubes is made by reaction of the aromatic ring with aryl radicals, produced by reduction of diazonium ions. In the case of conducting polymers, covalent functionalisation is brought about by reaction of polyanilines with diazotized aromatic amines (including amino terminated azo dyes).