Open for Discussion: Nanoparticles

By Barbara Sitzman and Regis Goode

How small are nanoparticles?

“Nano” is the metric prefix for 1 x 10-9, so a nanometer (nm) is a billionth of a meter. It comes from an ancient Greek word that means “dwarf.” Nanoparticles range from 1 to 100 nm in diameter. Without a microscope, we can only see particles larger than 10,000 nm.

Would you buy a roll-up smart phone?

“Nano” is the metric prefix for 1 x 10-9, so a nanometer (nm) is a billionth of a meter. It comes from an ancient Greek word that means “dwarf.” Nanoparticles range from 1 to 100 nm in diameter. Without a microscope, we can only see particles larger than 10,000 nm.

Why are nanoparticles so special?

Paper-thin smart phones are still on the research lab bench. Soon, you may be able to twist nanophones to fit your pocket. T-shirts with carbon nanotubes woven into the fabric are expected to keep them charged.

When the diameter of particles is 100 nm or less, their chemical and physical properties are unique and quite different from materials made with the same chemical elements, yet large enough to see. Nanoparticles’ unique characteristics are strongly influenced by their size and shape.

Nanoparticle clusters have a large surface-to-volume ratio. This means that most of their atoms sit on the surface, available to collide and ready to react.

These small reactive clusters could one day zoom through our bloodstream for speedy drug delivery or to attack cancerous tumors.

Are nanoparticles really new?

In addition to size, scientists are discovering that the shape of a nanoparticle matters. Flat disks bond best to tumors, and rod-shaped nanoparticles slip into cells at four times the rate of cylindrical nanoparticles.

Actually, nanoparticles were already here when the Earth was formed. Sea spray and volcanos spewed nanoparticles into our atmosphere. In the 9th century, Mesopotamian artisans created their pottery glitter with copper and silver oxides finely ground to nano-size.

Breath sensors could soon replace blood analyses

What is new about nanoparticles is our ability to manipulate matter at the atomic level, opening the door to many new applications. During the past 5 to 6 years, research, development, and consumer interest has increasingly been focused on nanotechnology.

You feel feverish and miserable, and then the doctor orders tests. But who likes getting needles stuck into their veins to withdraw a tube of blood? Some clinics quickly and painlessly analyze the gases you exhale for flu viruses. Breath sensors, composed of gold nanoparticles, carbon nanotubes, and silicon nanowires, help doctors diagnose various medical conditions by analyzing breath in just a few seconds.

Should we be concerned about nanoparticles?

We are not fully aware of the health and environmental risks presented by the use of nanoparticles; but scientists are trying to understand the potential risks and benefits of their widespread use.

Browse by Topic