The potential positive and negative effects of nanotechnology on the environment are discussed. Advances in nanotechnology may be able to provide more sensitive detection systems for air and water quality monitoring, allowing the simultaneous measurement of multiple parameters and real time response capability. Metal oxide nanocatalysts are being developed for the prevention of pollution due to industrial emissions and the photocatalytic properties of titanium dioxide nanoparticles can be exploited to create self-cleaning surfaces that reduce existing pollution. However, while nanotechnology might provide solutions for certain environmental problems, relatively little is known at present about the environmental impact of nanoparticles, though in some cases chemical composition, size and shape have been shown to contribute to toxicological effects. Nanotechnology can assist resource saving through the use of lightweight, high strength materials based on carbon nanotubes and metal oxide frameworks as hydrogen storage materials. Other energy related applications include nanostructured electrode materials for improving the performance of lithium ion batteries and nanoporous silicon and titanium dioxide in advanced photovoltaic cells. It is important to develop an efficient strategy for the recycling and recovery of nanomaterials and methods are needed to assess whether the potential benefits of nanotechnology outweigh the risks. Life cycle analysis will be a useful tool for assessing the true environmental impacts. r

Activation of vasa vasorum (the microvessels supplying the major arteries) at specific sites in the adventitia initiates their proliferation or 'angiogenesis' concomitant with development of atherosclerotic plaques. Haemorrhagic, leaky blood vessels from unstable plaques proliferate abnormally, are of relatively large calibre but are immature neovessels poorly invested with smooth muscle cells and possess structural weaknesses which may contribute to instability of the plaque by facilitation of inflammatory cell infiltration and haemorrhagic complications. Weak neovascular beds in plaque intima as well as activated adventitial blood vessels are potential targets for molecular imaging and targeted drug therapy, however, the majority of tested, currently available imaging and therapeutic agents have been unsuccessful because of their limited capacity to reach and remain stably within the target tissue or cells in vivo. Nanoparticle technology together with magnetic resonance imaging has allowed the possibility of imaging of neovessels in coronary or carotid plaques, and infusion of nanoparticle suspensions using infusion catheters or implant-based drug delivery represents a novel and potentially much more efficient option for treatment. This review will describe the importance of angiogenesis in mediation of plaque growth and development of plaque instability and go on to investigate the possibility of future design of superparamagnetic/perfluorocarbon-derived nanoparticles for imaging of the vasculature in this disease or which could be directed to the adventitial vasa vasorum or indeed intimal microvessels and which can release active payloads directed against primary key external mitogens and intracellular signalling molecules in endothelial cells responsible for their activation with a view to inhibition of angiogenesis.

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