The universe of nanoparticles―thinking about a world of small-scale

I spent some time by inventing questions which could be easily replied. Suddenly, one came in my mind: “A viral particle measures 80 nanometers. Transform the value into millimeters”. I expected 100% rate of success since the task was really elementary. Surprisingly, there were several students in my group, who were wrong.

The nano-world in the nature

Nanoparticles are formations of different shape with size varying mostly from 10 to 100 nanometers.In nature, virus represents a typical nanoparticle. Viruses are not included in living organisms because they are not able reproduce themselves within a host cell. Virus doesn’t have its own replication mechanism. It is an intracellular parasite entirely dependent on cellular system of protein synthesis.

Viral particle is formed by a short fragment of DNA encapsulated in lipid shape from about 10 to 200 nanometers in size. For comparison, the size of bacteria (for example these one causing the tonsillitis) reaches 1 micrometers.

Nanoparticles in daily life

Nanoparticles are everywhere around us. They are used in daily cosmetic products, food and textile industry, medicine, building technologies and many other fields.

Can we see them?

Yes. Using an electron microscope. The device is equipped with powerful electromagnetic lens. Emitted electrons bomb the sample in a vacuum chamber with stunning velocity. Some electrons go through, the others are reflected. Particle itself, highly magnified, can be seen on the diffusion screen in different shades of grey since there are electrons instead of light so there are not colors like in light microscopy.

What makes nanoparticle so unique

Many materials, for example carbon or silver when prepared in form of nanoparticles get miraculous properties. Nanoforms of carbon are extremely strong, silver is enhanced with antimicrobial properties.

Artificially prepared nanoparticles: some examples

• Colloidal gold

Dense round particles of gold in solution. Colloidal gold easily binds antibodies, make them visible therefore it is used in microscopy as marker. About potential use of gold nanoparticles in cancer cure you can read here.

• Fullerenes

Newly discovered, promising molecules especially in medicine. Fullerene cage-like molecule has space inside which make it attractive as possible vehicle for trafficking of diverse cargo during medical treatment.

• Graphene

Another carbon allotrope. Thin, theoretically one atom thick, layer of carbon hexagons and pentagons used for different purposes in computing and electronics.

• Silver

Silver is known for a long time as material lowering the bacterial activity. Silver nanoparticles are widely used in textile industry, medicine and household applications.

What about nanoparticles and our health

The word is enthusiastic when speaking about nanoparticles. But what about their impact on human health? Most of them are product of some kind of artificial synthesis. The environment, our dwellings and object of daily use are full of them. Of course, there are presented semi-natural nanoparticles as a product of combustion: soot particles in smoke.

What makes them a potential danger is ability of nanoparticles to penetrate inside human tissues where can be stored. Certain nanoparticles were described as elements damaging DNA structure as you can read in this article.

The degree of harmfulness derives from the size of the particle and its shape. As a result of such findings, a new branch has developed along with nanoscience: nanotoxicology.