British scientist: Nanoparticles might move from mom to fetus

LONDON, Jan. 14, 2004 — Vyvyan Howard, one of Europe’s leading researchers of nanoparticle toxicity, is set to report on the possibility that one form of nanoscale material may be transferred from a mother into her fetus.

Howard outlined his preliminary findings at Nanotox 2004, a conference at Daresbury Laboratories in Warrington, England, he helped organize to discuss the biological interactions of nanoparticles and their implications for human health. Howard is a senior lecturer at the University of Liverpool, where he leads its toxicopathology research group, and a past president of the Royal Microscopal Society.

At the conference, Howard described how researchers have been injecting gold nanoparticles into pregnant rats to determine whether they can be transferred across to the fetus.

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Howard had hoped to report the findings at the event, but assessments of his results had taken longer than he hoped. However, initial images displayed at the conference show unidentified particles in the fetus. “We are still trying to identify what these particles are, but we think they may be the gold particles,” Howard said. Results of the experiments will be available in the next few weeks.

“This research [on possible transfer of nanoparticles to the fetus] could flag up a new, particular, hazard of nanoparticles; it would provide new evidence to show that there is even more cause for concern” said Doug Parr, chief scientist for Greenpeace.

However, according to Kevin Ausman executive director of the Center for Biological and Environmental Nanotechnology at Rice University, it is still too early to establish the transfer of nanoparticles to the fetus.

“It’s not really an issue that has been addressed yet,” Ausman said. “We have to establish whether nanoparticles can be accumulated in the body and then we can see if they have a chronic effect. If that can be proved it will then be of interest to see if they can be transferred to the fetus. It hasn’t been demonstrated that nanoparticles can penetrate the skin, so it’s perhaps premature to try and establish if they can be transferred to the fetus.”

Gold particles are of interest to the nanotechnology industry in part because research has focused on how they may be used to kill off cancerous cells. Gold nanoshells, when injected into tumors and shone with a near infrared light, heat up and kill the cancer cells, but do not affect the surrounding tissue.

Howard’s findings were presented as part of an overview of 27 separate papers that look at how nanoparticles can be absorbed into the body and distributed to the organs. Howard cited several studies that appear to show that “once ultrafine particles have been internalized there appears to be a natural ‘passageway’ for them to travel around the body.”

The conference was largely focused on manufactured nanoparticles, although there was some focus on nanoscale pollutants from combustion engines.

Howard’s comments came as part of a series of presentations and papers examining the toxic affects of nanoparticles. Among the other presenters was Ken Donaldson of the University of Edinburgh Medical School.

Donaldson argued for a new way of classifying nanoparticles based on their toxicity. “Not all nanoparticles … cause inflammation,” he said. Rather, he added “the classification by size is not simply enough; more research is needed to understand the full spectrum of toxicities that might arise from nanoparticles of different compositions.”

Howard has been a leading advocate for strict controls on the release of nanoparticles. He has argued that particle size may as much a contributory factor in the toxicity of nanoparticles as their chemical composition.

His arguments were backed up by a paper from David Jefferson at the University of Cambridge. Jefferson said that the catalytic effects of materials — notably metal oxides — can change dramatically at small sizes. “The nature of the reactivity of oxide particles may change with size.” As materials react differently at very small sizes, “we don’t know what the effects of these nanoparticles might be.”

Nanoscale zinc oxide and titanium dioxide are used in some brands of cosmetics and sunscreen.

This conference is the latest in separate efforts around the world to study the possible risks associated with nanoscale manufacturing. The U.S. Environmental Protection Agency is expected to explore the effects of nanoparticles on pregnant women and may examine the transmission of nanoparticles to the fetus as part of its investigation into the effects of nanomaterials on humans and the environment.

Britain’s Royal Society is also expected to release comments on nanoparticles and the human health in the next few weeks after meeting with health practitioners and scientists. The meetings form part of the Society’s broader investigation into nanotechnology, the results of which are expected to be released in the spring.


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