This essay by Chunli Bai, executive vice president of the Chinese Academy of Sciences (CAS), explains the reasons behind the rapid progress of nanotechnology in China. A key factor, says Bai, has been "extraordinary" government support for the field since the early 1980s, which led to the creation of research institutes and significant grant money. But, cautions Bai, public communication on nanotechnology research, and ongoing monitoring and assessment of nanotechnology risks is needed.

This Nanomedicine paper reviews a range of strategies based on nanotechnology that are currently being used or tested to improve HIV/AIDS treatment and prevention. The authors review nanomedical advances in antiretroviral therapy, gene therapy, immunotherapy, vaccines and microbicides.

They conclude that nanotechnology promises great improvements in all of these areas but they warn that the field still faces many challenges including the toxicity of nanomaterials, their stability in physiological settings and the question of how to mass-produce them.

This scientific article, written by researchers at Rice University in the United States, describes how magnetite (iron) nanocrystals — or 'nanorust' — can be used to remove arsenic from contaminated water. The authors describe the discovery of unexpected magnetic interactions between nanoparticles of rust that mean they can be easily extracted from water using a hand-held magnet.

Iron is well known for its ability to bind arsenic and the researchers' experiments show that by suspending the nanoparticles of rust in arsenic-contaminated water, arsenic levels were reduced to well below accepted standards for drinking water.

This commentary, by South African scientists Thembela Hillie and Mbhuti Hlophe, examines nanoscience's potential to solve the technical challenges associated with removing pollutants from water. The authors describe a range of nano-based water treatment technologies already in the marketplace and discuss how nanofiltration membranes can be used in low-cost methods to produce safe drinking water. They highlight a case study in South Africa where such membranes were used to treat brackish groundwater.

The authors emphasise the importance of technology transfer in getting nano-based solutions to the countries that need them, arguing that direct transfer does not often work. Rather, what developing countries need are approaches that combine technology transfer with technology adaptation and adoption — involving local stakeholders in establishing water treatment devices and developing local capacity to use them.

This paper by scientists at the University of Hyderabad examines the nanoscience debate in India. Nanoscience's revolutionary potential and economic benefits are assessed against ethical, legal, social and environmental (ELSE) issues.

The authors present commercial applications, investment, risks and regulatory mechanisms, using the case of Bt cotton in India to show the implications of a new technology. They argue that India's diverse socio-cultural landscape means that nanoscience is likely to have uneven and multilayered effects.

India's scientists do not advocate regulation at the current stage of research — so as not to slow down development, say the authors. But they add that a broad-based and transparent regulatory body to address ELSE issues and funding for research on them would be beneficial.