Nanomaterials – tiny trouble?

What are they?

Nanomaterials are materials that are extremely small. Think molecule-scale. Like glucose molecules and the diameter of DNA. Like viruses.

As a comparison, a human hair (pretty narrow, right?) is approximately 80,000 nanometres thick.

Although there is currently no internationally agreed definition for ‘nanomaterial’, the range of 1-100 nanometres is generally referred to as ‘nanoscale’.

AICIS, the Australian industrial chemicals regulator, defines a nanomaterial as having at least one dimension 100 nanometres or less.¹

nanoscale diagram

Science spot

Nanomaterials can occur naturally, be produced by human activities, or be engineered by man.

Types of nanomaterials There are two main ways to engineer nanomaterials: to build them up chemically from the molecular level, or to mill them down mechanically from larger substances.

Nanomaterials can behave differently to larger particles of the same substance. For example, zinc sunscreen (non-nano) goes on your skin white, while nano-zinc sunscreen is transparent. Nano-aluminium has antibacterial properties, while aluminium foil (for example) does not.

What's the myth?

Nanomaterials can have novel properties based on their size.

This means potential opportunities for new technologies based on nanomaterials. One of the most appealing areas of nanotechnology research is in medical applications such as targeted drug delivery, diagnostics, implants and chemotherapy.

But novel properties can also raise the question of safety. It has been suggested that engineered nanoparticles are just too risky. For example, Friends of the Earth have a long-running (but fairly silent, at present) anti-nano campaign.

It’s a legitimate question that should be asked – are nanomaterials safe for humans and the environment?

But as we will see below, questioning the safety of nanomaterials as a whole category is not the way to go.