James Chapman

Period four metal nanoparticles on the inhibition of biofouling.

Biofilms present operational problems to a variety of industrial areas including but not limited to, medicine, water treatment, sensor sensitivity and shipping. Bacterial adhesion resides as a tiny monolayer and builds-up over time with the production of protective slimes known as extracellular polymeric substances (EPS) forming the biofilm. Infection, inefficiency and diminution of quality are caused by biofilms, which have the potential to be prohibitively expensive to repair. The value of an effective coating that prevents the adhesion of bacteria and subsequent fouling is paramount in preserving sensitivity and longevity of a subjected operational substrate. Polymer and sol-gel (SG) based coatings tender a matrix for the introduction of biocides and antimicrobial agents that offer this prevention. They present a relatively cheap and optically clear platform that can then be doped with the antimicrobial agent. This proves useful in transferring across a range of industries that may require a transparent function to the coating. Nanoparticles offer a means of new line research in combating biofouling and biocorrosion with interest stemming from silver metal nanoparticles (MNPs) that already offer antimicrobial property. The aim of this work is to investigate period four metal nanoparticles for any antimicrobial potential they offer, in the prevention of fouling in the early stages. The research presented herein uses a range of period four MNPs synthesised through an adapted polyol reduction, which have then been doped into SG coatings and tested for their efficacy in preventing levels of biofouling. After a 7-day freshwater study results showed that MNPs prevent levels of biofouling upto 125% compared to the SG blank. The work uses bacterial enumeration, minimum inhibitory concentration (MIC), surface characterisation and slime and biomass analysis to complete a range of studies in assessing the level of fouling observed on the test substrates.

Antifouling performances of macro- to micro- to nano-copper materials for the inhibition of biofouling in its early stages

Copper has been known to possess antimicrobial properties since as far back as the Phoenician era where ship hulls were copper sheathed to prevent the inevitable effects of biofouling. As a consequence of evolving scientific research and development, the realisation of novel materials and agents has enabled new scientific branches - such as nanotechnology. In this paper we investigate the performance of different forms of copper (macro, micro and nano) for application as antifouling materials. Samples are deployed in SmartBay Ireland for four weeks and analysed for evidence of biofouling. It was found that copper in its nano form, produced the greatest antifouling effectiveness in both PDMS and sol-gel matrices.

The gastrointestinal tract microbiota of the Japanese quail, Coturnix japonica

Microbiota in the gastrointestinal tract (GIT) plays an essential role in the health and well-being of the host. With the exception of chickens, this area has been poorly studied within birds. The avian GIT harbours unique microbial communities. Birds require rapid energy bursts to enable energy-intensive flying. The passage time of feed through the avian GIT is only 2–3.5xa0h, and thus requires the presence of microbiota that is extremely efficient in energy extraction. This investigation has used high-throughput 16S rRNA gene sequencing to explore the GIT microbiota of the flighted bird, the Japanese quail (Coturnix japonica). We are reporting, for the first time, the diversity of bacterial phylotypes inhabiting all major sections of the quail GIT including mouth, esophagus, crop, proventriculus, gizzard, duodenum, ileum, cecum, large intestine and feces. Nine phyla of bacteria were found in the quail GIT; however, their distribution varied significantly between GIT sections. Cecal microbiota was the most highly differentiated from all the other communities and showed highest richness at an OTU level but lowest richness at all other taxonomic levels being comprised of only 15 of total 57 families in the quail GIT. Differences were observed in the presence and absence of specific phylotypes between sexes in most sections.

Sebacic and succinic acid derived plasticised PVC for the inhibition of biofouling in its initial stages

Aim In this work, we report the use of plasticized polyvinyl chloride (PVC) as a potential antifouling coating material. The materials contain a variety of sebacic and succinic acid-derived plasticizers providing a variation in molecular shape and structure; diethyl succinate (DESn), di-(2-ethylhexyl sebacate) (DEHS), dibutyl sebacate (DBS), and diethyl sebacate (DES). Each plasticizer from the sebacate group possessed the same basic C10H16O4 moiety with varied dialkyl terminated groups, affording a different range of homologous series plasticizers. This work investigates whether branching of the side substituted alkyl chains on each plasticizer molecule affects microorganism attachment and subsequent fouling. Materials and Methods The plasticized polymers are spin coated to create thin films for testing. In order to determine the antifouling capacity of the materials, the polymer coatings underwent a series of analyses for biomass determination, glycocalyx production, and protein and carbohydrate adsorption. Topological and morphological characterization was performed using scanning electron microscopy and atomic force microscopy. Results After a 7 day laboratory biofouling study it was found that the plasticizers with increased alkyl branching, DESN, and DEHS revealed the greatest degree of prevention of microorganism colonization and attachment thus significantly reducing the initial formation of biofilms by up to 65% in some biofouling assays when compared to the unplasticized PVC blank.

Biomimetics for early stage biofouling prevention: templates from insect cuticles

A biomimetic antifouling material study was carried out utilising superhydrophobic cicada and dragonfly wings replicated with a polymer (epoxy resin). They were tested in a marine biofouling study for up to 1 week in addition to biofouling assays of protein, carbohydrate and DNA absorption. The materials were compared against a commercial antifouling paint and a polymeric smooth surface constituting a control sample. The replicated surfaces demonstrated superior antifouling properties in comparison to the control and similar efficiency in DNA (10% reduction), protein and carbohydrate adsorption (15%) to the commercial anti-fouling paint. As the fabricated surfaces have roughness at the nanometre scale it is probable that the low adsorption properties, at least in the early stages, may be related to air trapped at the surface. Interestingly the most disordered replicated surface (dragonfly wing replicate) demonstrated the lowest values of absorption.

Novel pre-treatment of zeolite materials for the removal of sodium ions: potential materials for coal seam gas co-produced wastewater

Coal seam gas (CSG) is the extraction of methane gas that is desorbed from the coal seam and brought to the surface using a dewatering and depressurisation process within the saturated coalbed. The extracted water is often referred to as co-produced CSG water. In this study, co-produced water from the coal seam of the Bowen Basin (QLD, Australia) was characterised by high concentration levels of Na+ (1156xa0mg/L), low concentrations of Ca2+ (28.3xa0mg/L) and Mg2+ (5.6xa0mg/L), high levels of salinity, which are expected to cause various environmental problems if released to land or waters. The potential treatment of co-produced water using locally sourced natural ion exchange (zeolite) material was assessed. The zeolite material was characterized for elemental composition and crystal structure. Natural, untreated zeolite demonstrated a capacity to adsorb Na+ ions of 16.16xa0mEq/100xa0g, while a treated zeolite using NH4+ using a 1.0xa0M ammonium acetate (NH4C2H3O2) solution demonstrated an improved 136xa0% Na+ capacity value of 38.28xa0mEq/100xa0g after 720xa0min of adsorption time. The theoretical exchange capacity of the natural zeolite was found to be 154xa0mEq/100xa0g. Reaction kinetics and diffusion models were used to determine the kinetic and diffusion parameters. Treated zeolite using a NH4+ pre-treatment represents an effective treatment to reduce Na+ concentration in coal seam gas co-produced waters, supported by the measured and modelled kinetic rates and capacity.

Emerging biomaterials and strategies for medical applications : a review /

Abstract The creation of new materials is one of the fundamental driving forces between research and industry and lays the foundation for new products to enhance health and well being for the future. Antibacterial materials are an active area of research but also an economic sector in full expansion that addresses many application domains. It is also a world priority in terms of reducing infection in humans for improved life and well being. Healthcare is one the largest and most rapidly expanding needs of modern society, and smart approaches and materials are required to extend the boundaries required to improve the field. In this paper, we systematically review a series of biomaterials and strategies that have emerged over the last decade. In particular, focus has been driven around the nanorealm. Some of the diverse arenas surrounding the nanodomain and applications include drug screening technologies, biocompatibility, emerging approaches and biomimetics. In a wider front, intelligent materials are where the next phases of research are driven, some of which are discussed herein.

Selenium nanoparticles in poultry feed modify gut microbiota and increase abundance of Faecalibacterium prausnitzii

The poultry industry aims to improve productivity while maintaining the health and welfare of flocks. Pathogen control has been achieved through biosecurity, vaccinations and the use of antibiotics. However, the emergence of antibiotic resistance, in animal and human pathogens, has prompted researchers and chicken growers alike to seek alternative approaches. The use of new and emerging approaches to combat pathogen activity including nanotechnology, in particular, silver nanoparticles (NPs), has been found to not only eradicate pathogenic bacteria but also include issues of toxicity and bioaccumulation effects. Other novel metal nanoparticles could provide this pathogen reducing property with a more tailored and biocompatible nanomaterial for the model used, something our study represents. This study investigated the benefits of nanomaterial delivery mechanisms coupled with important health constituents using selenium as a biocompatible metal to minimise toxicity properties. Selenium NPs were compared to two common forms of bulk selenium macronutrients already used in the poultry industry. An intermediate concentration of selenium nanoparticles (0.9xa0mg/kg) demonstrated the best performance, improving the gut health by increasing the abundance of beneficial bacteria, such as Lactobacillus and Faecalibacterium, and short-chain fatty acids (SCFAs), in particular butyric acid. SCFAs are metabolites produced by the intestinal tract and are used as an energy source for colonic cells and other important bodily functions. Selenium nanoparticles had no significant effect on live weight gain or abundance of potentially pathogenic bacteria.

Nanoparticle and biomaterial characterisation techniques

Abstract The physicochemical properties of nanoparticles and biomaterials exert influences over their interactions with cells and consequently play an important role when introduced into any given system. Characterisation of these said materials is a detailed and, above all, a cross-disciplinary relationship of physical, chemical, mechanical, surface, in vitro and in vivo multi-integrated research topics. The biocompatibility of a functional structure with desired properties is affected by the biomaterials’ structural characteristics and building block pathways. Moreover, the sensitivity, depth of field, resolution and dimension of a given material also make structural analysis of a nano-biomaterial particularly challenging to characterise. In this paper, we discuss the use of biomaterial characterisation techniques (fluorescent and optical) to characterise structural aspects of biomaterials, with the aim of improving both the understanding and relationship between a biomaterials’ structure and its functionality.

Continuous high-frequency monitoring of estuarine water quality as a decision support tool a Dublin Port case study /

High-frequency, continuous monitoring using in situ sensors offers a comprehensive and improved insight into the temporal and spatial variability of any water body. In this paper, we describe a 7-month exploratory monitoring programme in Dublin Port, demonstrating the value of high-frequency data in enhancing knowledge of processes, informing discrete sampling, and ultimately increasing the efficiency of port and environmental management. Kruskal–Wallis and Mann–Whitney tests were used to show that shipping operating in Dublin Port has a small–medium effect on turbidity readings collected by in situ sensors. Turbidity events are largely related to vessel activity in Dublin Port, caused by re-suspension of sediments by vessel propulsion systems. The magnitudes of such events are strongly related to water level and tidal state at vessel arrival times. Crucially, measurements of Escherichia coli and enterococci contamination from discrete samples taken at key periods related to detected turbidity events were up to nine times higher after vessel arrival than prior to disturbance. Daily in situ turbidity patterns revealed time-dependent water quality “hot spots” during a 24-h period. We demonstrate conclusively that if representative environmental assessment of water quality is to be performed at such sites, sampling times, informed by continous monitoring data, should take into account these daily variations. This work outlines the potential of sensor technologies and continuous monitoring, to act as a decision support tool in both environmental and port management.