HOWZAT

This knowledge gap is of greatest concern when considering the health and safety of those involved in the manufacture of nanoparticles, for whom there might be heavy accidental exposure. It is not known for example whether carbon nanotubes — which are just what they sound like — could join together, forming a fibre with similar effects to asbestos. The effects on the environment should there be a release are similarly unknown.

In a welcome piece of transparency, a recent report from the Department for Environment, Food and Rural Affairs has identified these knowledge gaps, many of which are crucial to devising proper safety regulations. However, despite the smoke and mirrors in the report on funding for this work, the reality is that the Government has failed to allocate money for this vital research to the consternation of the Royal Society and Royal Academy of Engineering.

There is reassuring news, however. Human immune systems are configured to deal with nanoparticles as many of the viruses and allergens that we inhale and eat every day are tiny. And, as Anthony Seaton, a professor emeritus at Aberdeen University says: “Humans have been exposed to nanoparticles since they first started lighting fires.” Nanoparticles are found in combustion products from fires and engines. City dwellers habitually breathe in millions, if not billions, each day as they walk around busy streets. “Unless nanoparticles are substantially more dangerous than these, surely there can’t be that big a problem?” says Ken Donaldson.

Another concern is about location, when particles are found where they shouldn’t be. They can be safe in one place in the body, but not in another. “It’s rather like water being OK in your body but not being all right if it turns up in your lungs when you have pneumonia,” Ruth Duncan says.

There have been reports of inhaled nanoparticles reaching the brain in animal studies, although this work has not been replicated. Some animal work has shown that inhaled carbon nanotubes can cause serious lung damage. There is also evidence that carbon nanoparticles are capable of causing greater inflammation in the lungs than larger-sized particles. And there is a suspicion, not proven, that the heart attacks associated with the great smogs of London were a nanoparticle effect. The suggestion is that they altered blood clotting, although no one is sure of the mechanism. Many scientists point out that manufactured nanoparticles are “clean”, whereas those found in atmospheric pollution are dirty, carrying heavy metals and so forth that make them more reactive and thus potentially more dangerous to health.

We live with nanoparticles daily and always have done. But the fact that we do so should not blind us to the potential for harm from nanoparticles that are new to us, which need to be subjected to full safety reviews before use. Meanwhile, nanomedicine offers a future of more effective drugs, diagnostics and tissue repair. The future is tiny.

Nanomedicine in action

Ovarian cancer Many nanomedicines involve the use of liposomes: hollow spheres of fat that can enclose medicines. The fatty layer contains the drug until it comes into contact with the outer membrane of a target cell and then dissolves. The ovarian cancer drug Doxil uses exactly this technique to deliver chemotherapy drugs accurately.

Breast cancer The breast cancer drug Abraxane, recently approved in America, is actually the existing anti-cancer drug Taxol re-engineered into a nanoparticle. This hitches a ride on the protein albumin, which is already in the body, and allows the drug to cross blood-vessel walls to the cancer.

Radiotherapy Nanogenerators are now under development. These are nanoparticles that generate radioactivity and then go directly to cancerous tissue. This gives small doses of radiotherapy exactly where it is required, reducing side-effects.

Explore Health News

• Swine flu

Times Recommends

• Why Witherspoon is highlighting domestic violence
• No, MP does not stand for Mostly Plastered
• Don’t bottle out of your champagne moment