Biological removal of nitrogen oxides by microalgae, a promising strategy from nitrogen oxides to protein production.

Nitrogen oxides (NOx) are the components of fossil flue gases that give rise to serious environmental and health hazards. Among the available techniques for NOx removal, microalgae-based biological removal of NOx (BioDeNOx) is a promising and competent technology with eco-friendly path of low energy and low-cost solution for the pollution. In this review article, current biological technologies including bacteria-based and microalgae-related BioDeNOx are discussed. Comparing to direct BioDeNOx approach, indirect BioDeNOx by microalgae is more promising since it is more stable, reliable and efficient. By transforming inorganic nitrogen nutrients to organic nitrogen, microalgae can potentially play an important role in converting NOx into high-value added products. The microalgae-based BioDeNOx process displays an attractive prospect for flue gas treatment to reduce environmental NOx pollution and potentially supply protein products, establishing an efficient circular-economy strategy.

All carbon materials pn diode.

Semiconductor pn junctions are elementary building blocks of many electronic devices such as transistors, solar cells, photodetectors, and integrated circuits. Due to the absence of an energy bandgap and massless Dirac-like behaviour of charge carriers, graphene pn junction with electrical current rectification characteristics is hardly achieved. Here we show a graphene pn junction diode can be made exclusively from carbon materials by laminating two layers of positively and negatively charged graphene oxides. As the interdiffusion of oppositely charged mobile counterions, a built-in potential is created to rectify the current by changing the tunnelling probability of electrons across the junction. This graphene diode is semi-transparent, can perform simple logic operations, and since it has carbon nanotubes electrodes, we demonstrate an all carbon materials pn diode. We expect this graphene diode will expand material choices and provide functionalities (e.g. grafting recognition units on graphene oxides) beyond that of traditional semiconductor pn junctions.

ß-Cyclodextrin Functionalized Nanoporous Graphene Oxides for Efficient Resolution of Asparagine Enantiomers.

Efficient resolution of racemic mixture has long been an attractive but challenging subject since Pasteur separated tartrate enantiomers in 19th  century. Graphene oxide (GO) could be flexibly functionalized by using a variety of chiral host molecules and therefore, was expected to show excellent enantioselective resolution performance. However, this combination with efficient enantioselective resolution capability has been scarcely demonstrated. Here, nanoporous graphene oxides were produced and then covalently functionalized by using a chiral host material-ß-cyclodextrin (ß-CD). This chiral GO displayed enantioselective affinity toward the l-enantiomers of amino acids. In particular, >99 % of l-asparagine (Asn) was captured in a racemic solution of Asn while the adsorption of d-enantiomer was not observed. This remarkable resolution performance was subsequently modelled by using an attach-pull-release dynamic method. We expect this preliminary concept could be expanded to other chiral host molecules and be employed to current membrane separation technologies and finally show practical use for many other racemates.

Photo-Modulated Therapeutic Protein Release from a Hydrogel Depot Using Visible Light.

The use of biomacromolecular therapeutics has revolutionized disease treatment, but frequent injections are required owing to their short half-life in vivo. Thus there is a need for a drug delivery system that acts as a reservoir and releases the drug remotely "on demand". Here we demonstrate a simple light-triggered local drug delivery system through photo-thermal interactions of polymer-coated gold nanoparticles (AuNPs) inside an agarose hydrogel as therapeutic depot. Localized temperature increase induced by the visible light exposure caused reversible softening of the hydrogel matrix to release the pre-loaded therapeutics. The release profile can be adjusted by AuNPs and agarose concentrations, light intensity and exposure time. Importantly, the biological activity of the released bevacizumab was highly retained. In this study we demonstrate the potential application of this facile AuNPs/hydrogel system for ocular therapeutics delivery through its versatility to release multiple biologics, compatibility to ocular cells and spatiotemporal control using visible light.

Nucleic acid from beans extracted by ethanediamine magnetic particles.

Ethanediamine magnetite nanoparticles (EDAMPs) were used as adsorbents to isolate genomic DNA from various bean-species. A "single-pot" preparation of EDAMPs was described. Further characterization, including transmission electronic microscopy (TEM), scanning electronic microscopy (SEM), thermo-gravimetric analysis (TGA), X-ray powder diffraction (XRD) and Fourier Transform Infrared Spectrophotometer (FT-IR) were used to demonstrate the efficiency of this simple and general identification method. The EDAMPs provided excellent yields of genomic DNA. The isolated DNA was suitable for use in further applications by the Polymerase Chain Reaction (PCR) for the detection of Genetically Modified (GM) food and non-GM food. The EDAMPs are effective for bioseparation applications.

Self-assembled gold coating enhances X-ray imaging of alginate microcapsules.

Therapeutic biomolecules produced from cells encapsulated within alginate microcapsules (MCs) offer a potential treatment for a number of diseases. However the fate of such MCs once implanted into the body is difficult to establish. Labelling the MCs with medical imaging contrast agents may aid their detection and give researchers the ability to track them over time thus aiding the development of such cellular therapies. Here we report the preparation of MCs with a self-assembled gold nanoparticle (AuNPs) coating which results in distinctive contrast and enables them to be readily identified using a conventional small animal X-ray micro-CT scanner. Cationic Reversible Addition-Fragmentation chain Transfer (RAFT) homopolymer modified AuNPs (PAuNPs) were coated onto the surface of negatively charged alginate MCs resulting in hybrids which possessed low cytotoxicity and high mechanical stability in vitro. As a result of their high localized Au concentration, the hybrid MCs exhibited a distinctive bright circular ring even with a low X-ray dose and rapid scanning in post-mortem imaging experiments facilitating their positive identification and potentially enabling them to be used for in vivo tracking experiments over multiple time-points.

A simple way to track single gold-loaded alginate microcapsules using x-ray CT in small animal longitudinal studies.

The use of alginate based microcapsules to deliver drugs and cells with a minimal host interaction is increasingly being proposed. A proficient method to track the position of the microcapsules during such therapies, particularly if they are amenable to commonly used instrumentation, would greatly help the development of such treatments. Here we propose to label the microcapsules with gold nanoparticles to provide a bright contrast on small animal x-ray micro-CT systems enabling single microcapsule detection. The microcapsules preparation is based on a simple protocol using inexpensive compounds. This, combined with the widespread availability of micro-CT apparatus, renders our method more accessible compared with other methods. Our labeled microcapsules showed good mechanical stability and low cytotoxicity in-vitro. Our post-mortem rodent model data strongly suggest that the high signal intensity generated by the labeled microcapsules permits the use of a reduced radiation dose yielding a method fully compatible with longitudinal in-vivo studies. FROM THE CLINICAL EDITOR: The authors of this study report the development of a micro-CT based tracking method of alginate-based microcapsules by incorporating gold nanoparticles in the microcapsules. They demonstrate the feasibility of this system in rodent models, where due to the high signal intensity, even reduced radiation dose is sufficient to track these particles, providing a simple and effective method to track these commonly used microcapsules and allowing longitudinal studies.

Extracting genomic DNA of foodstuff by polyamidoamine (PAMAM)-magnetite nanoparticles.

Although genetically modified (GM) food is becoming increasingly available, consumers are showing a growing awareness about the need to identify GM and non-GM foodstuff: the reliable identification of GM/non-GM food is therefore an important tool in the social, health and safety debates. The present research responds to this need (i) through developing a novel "single-pot" preparation of PAMAM magnetite nanoparticles (PMNPs) and by fully defining their specific characteristics; (ii) by demonstrating the capability of the PMNPs to isolate genomic DNA from different sample foods; and (iii) by experimentally demonstrating the identification of the isolated DNA by gel-electrophoresis, thus being capable of screening GM and non-GM food.