Free and Fixed Engineered Nanoparticles

Much of the recent speculation on the effects of engineered nanoparticles has focused on the free form, i.e. those not physically or chemically bound to larger structures. This has a certain logic given the relative mobility and ease of uptake into organisms of the free form. Nevertheless, the fixed form needs to be considered in aquatic systems because (a) the fixed form must have similar activity to the free form (or else it would not be useful commercially), (b) the fixed form may be...

References

ETC Group, No Small Matter II The Case for a Global Moratorium. Size Matters ETC Group, 2003. 2. E. Hood, Environ. Health Perspec., 2004, 112, A741-A749. 3. The Royal Society and The Royal Academy of Engineering, Nanoscience and nanotechnologies, The Royal Society and The Royal Academy of Engineering, 2004. 4. J.C. Davies, Managing the effects of nanotechnology, Woodrow Wilson International Center for Scholars, Project on Emerging Nanotechnologies, 2006. 5. A. Hett, Nanotechnology. Small...

Fate and Behaviour in Natural Aquatic Systems

When considering the fate, behaviour and ecotoxicology of engineered nanoparticles, it is perhaps most obvious to consider naturally occurring nanoparticles and this section will do this. Extensive reviews and discussion pieces in this area are now available36 39 and so this section focuses on only the main factors of relevance to engineered nanoparticles. These areas are structural determination and analysis, physical-chemical interaction with pollutants, pathogens and nutrients, impact on...

Definitions

As part of a major report commissioned by the UK Government from the Royal Society and the Royal Academy of Engineering in the UK, entitled ''Nanoscience and nanotechnologies opportunities and uncertainties'',3 the following definitions were used Nanoscience is the study of phenomena and manipulation of materials at atomic, molecular and macromolecular scales, where properties differ significantly from those at a larger scale. Nanotechnologies are the design, characterisation, production and...

Primary Emissions

In common with air pollutants in general, nanoparticles can be either primary or secondary. The term primary refers to those that are directly emitted, such as from road traffic exhaust and industrial combustion processes. The United Kingdom has developed a national inventory of emissions of nanoparticles (expressed as the mass of particles less than 0.1 mm diameter or PM01) and the inventory for 19981 appears in Figure 1. It may be seen that this is dominated by emissions from road traffic (62...

Dendrimers

Although linear polymers may be considered to be of nanomeric dimensions, there is one specific group of polymers that is designed to exploit its nanomeric size and characteristics. These are dendrimers and they are large and complex molecules with very well-defined structures. They are almost perfectly monodisperse macromolecules with a regular and highly branched three-dimensional architecture. Dendrimers can act as biologically active carrier molecules in drug delivery, to which can be...

Nanoparticle Size Distribution Measurement

3.5.1 Measuring Size Distribution using Particle Mobility Analysis. The most common instrument used for measuring size distributions of aerosols of nano-particles is the Scanning Mobility Particle Sizer SMPS . The SMPS is capable of measuring aerosol size distribution in terms of particle mobility diameter from approximately 3 nm up to around 800 nm, although multiple instruments typically need to be operated in parallel to span this range. A schematic diagram is given in Figure 6. It comprises...