Nanoparticles in anti-microbial materials: use and characterisation

Many nanomaterials exhibit anti-microbial properties and demand for such materials grows as new applications are found in such areas as medicine, environmental science and specialised coatings. This book documents the most up to date research on the area of nanoparticles showing anti-microbial activity and discusses their preparation and characterisation. Further materials showing potential anti-microbial properties are also discussed. With its user-friendly approach to applications, this book is an excellent reference for practical use in the lab. Its emphasis on material characterisation will benefit both the analytical and materials scientist. Frequent references to the primary literature ensure that the book is a good source of information to newcomers and experienced practitioners alike. Chapters devoted to nanoparticles, microbial impacts on surfaces and molecular biology will be essential reading, while chapters on characterisation ensure this book stands out in the field

Characterisation of nano-antimicrobial materials

The potential applications of nano-antimicrobial materials are well recognised. A large suite of characterisation techniques are available for the study of nano-antimicrobial materials. The choice of technique depends on the material properties in question and the information required. The focus of this chapter is on the surface and interface techniques as these provide information on material activity and efficacy. Antimicrobial properties of a nanomaterial must be characterised in terms of two interrelated aspects. The nature of the chemical and physical properties of the nanomaterial in question must be fully characterised in terms of, i.e. particle morphology and the elemental composition of the particle. Subsequently, it is necessary to characterise the material in terms of antimicrobial potential. This chapter provides a general guide and overview of characterisation techniques available to researchers studying nano-antimicrobial materials, including key microscopic methods, spectroscopic methods, and some physical surface characterisation methods. The chapter identifies how these techniques can be used to study the physical characteristics of the nanomaterials themselves and the antimicrobial effects on the material surface

Combating bio-fouling of sensors and environmental platforms in the marine environment

Bio-fouling is a ubiquitous natural process whereby organisms such as bacteria, algae or invertebrates form a living biological layer, typically at the interface between a solid surface and an aqueous environment. The build up of biofouling is a process that can impair the function of many artificial mechanical devices across a number of different disciplines, ranging from medicine to engineering and marine transport. This work shows the development of novel materials based on bio-inspired design and novel polymeric coatings for prevention of anti-fouling on sensor housings. Results of tested anti-fouling coatings are presented. The effect of topographic features is shown to impact on the settlement of diatoms in the early stages of biofilm formation. Novel polymeric coatings show promise in prevention of bacterial attachment. The results from the deployment of antifouling materials together with real-time water quality data from the test site is shown

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

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

Versatile self-cleaning coating production through sol–gel chemistry

The performance of optical devices is dependent on their optical transparency (OT). This is evident when such devices are exposed to environmental conditions that can reduce OT. The development of a robust, transparent and self-cleaning coating is highly desirable, for applications likeoptical windows and solar panels. This work reports the design of such coatings based on a hydrophobic thin film fabricated using a sol-gel process. Coating properties were optimised by modification of the surface topography of the coatings, achieved by the incorporation of silica nanoparticles(NPs). The coating was characterised by water contact angle(WCA), scanning electron microscopy(SEM) and white light interferometry (WLI). The efficacy and robustness of the coating foroptical application was assessed

Bioinspired synthetic macroalgae : examples from nature for antifouling applications

The demand to develop a novel, environmentally friendly antifouling (AF) material is ever increasing. An attractive option in developing such a material is biomimicry—learning from nature's own designs and solutions and transferring them to solve problems that affect human day-to-day living. In order to achieve this goal the actual mechanisms and strategies that evolution has produced need to be elucidated from the subject species. The work presented herein investigated the role of surface topography and chemistry combined in a single material – a property that naturally exists in some common macroalgae. Saccharina latissima (sugar kelp) and Fucus guiryi (Guiry's wrack) were selected as a platform for “bioinspiration.” Here, the surfaces of the samples were characterised and then replicated using simple polymeric reproduction methods. Furthermore, a pre-extracted brominated furanone was doped into this matrix (0.05 μg ml−1). The replicated macroalgae samples containing the brominated furanone compound were compared in a 7-day marine study to investigate the effects of biofouling. The bioinspired samples directly demonstrated that combinatory approaches (using topography and chemistry) exhibited lower levels of biofouling. Here it is reported that both chemistry and topography demonstrated 40% less biofouling when compared to blanks in all of the pre-designed biochemical biofouling assays. This represents an attractive nontoxic alternative to the current state of the art

Monitoring the marine environment using a low-cost colorimetric optical sensor

Anthropogenic activities have led to increased stress on our marine and other aquatic environments. There is a pressing need to monitor, measure, understand and mitigate the causes of these pressures. This paper presents the development and preliminary testing of a low-cost colorimetric optical sensor to detect colour-linked events in the marine environment. Potential applications may include the detection of Harmful Algal Blooms (HAB), which due to the production of toxins have deleterious effects on marine ecosystems and can ultimately lead to human, fish, bird and mammal deaths. Preliminary results indicate the capability of the sensor to differentiate between the colour signatures of several environmental samples