Nanoparticles: An Overview of Applications and Health Effects

Are nanoparticles worth the benefits over the risks?

Nanoparticles are man-made or natural particles that have sizes ranging from 1 to 100 nanometre in size. Just for reference, one nanometre is one billionth of a metre (10-9).

In layman’s terms, a nanometre is really, really tiny; it’s a measurement you can’t see unless magnified. One strand of your hair is around 40,000 nanometres thick. The head of a pin is 1,000,000 nanometres thick.

What is a nanoparticle then?

Wait a minute. Let’s backtrack a little. Let’s recall a bit of high school physics and chemistry.

Don’t worry, there’s no pop quiz at the end. Everything around you is made up of matter. The car you drive, the cell phone you use, that MacBook Pro you spent so much on, your favourite chair, etc. are all made up of matter. Matter is anything that has mass and occupies space, even you are matter. Matter is made of atoms and molecules. Most atoms are 0.1-0.2 nanometres across. It's hard to grasp just how small a nanoparticle is!

Size comparison:
	The head of a pin	1,000,000 nm across	Visible with our eyes
	The page of a book	100,000 nm thick
	A human hair	40,000 nm thick
	A red blood cell	7000 nm across	Visible using a light microscope
	Bacteria	1000–10 000 nm
	Transistor on latest computer chips (there are up to 100 million of them)	100 nm	Visible with an electron microscope or other device to see these
	DNA molecule	2 nm wide
	Most atoms	0.1–0.2 nm
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Nanoparticles can be formed through the breakdown of larger particles naturally or by controlled production processes. Natural processes, industrial, and domestic human activities like cooking, manufacturing, road, and air transportation all release nanoparticles into the atmosphere. You may have nanoparticles inside your body without you knowing it.

In what types of products are nanoparticles found? What are their applications?

Nanoparticles are found and used in a very wide array of commercial and medical products. The products mentioned below may contain nanoparticles or are manufactured utilising nanotechnology (the technology used to produce nanoparticles). Below are some of the more common ones:

Titanium dioxide found in the following consumer products to make a better overall product.
- Elmer’s glue
- Coffee creamer, low-fat cottage cheese, Greek yoghurt, whipped cream frosting, ranch dressing, bubble gum and mints, cereals, shampoo, chocolate syrup
- Powder deodorants, toothpaste, sunscreens
The cerium oxide nanoparticles in diesel are for improvement in combustion.
The nanoparticles in tyres improve their quality and longevity.
Nanoparticles (called quantum dots) are sometimes used for site-specific imaging of cancer cells found in lymph nodes, blood vessels around the lungs, and tumours.
Some nanoparticles (called iron oxide nanoparticles) are used to detect cancer in the liver, lymph nodes, and bone marrow.
Several polymer and liposome-based nanoparticles are used as drug and gene delivery in cancer treatment, neurodegenerative diseases, and HIV/AIDS therapy.
Antibacterial properties are exhibited by silver nanoparticles found in wound dressings.

Are nanoparticles safe or harmful? What is the current scientific and medical stance on nanoparticles?

The correct answer would be, it depends. The problem with nanoparticles is that they have the same measurements (or dimensions) as some biological molecules found in your body, to which they can interact with and disrupt the structure of. The size, shape, and chemical composition of the nanoparticle are of particular concern when it comes to your health.
Research regarding the toxicity of nanoparticles when present in your body is accumulating as of now. It’s only until recently (2014) that scientists have found a reliable, inexpensive, and easy to reproduce method to measure the number of nanoparticles present in bodily fluids.

Health concerns stemming from exposure to nanoparticles include the following:
1. Inhaled nanoparticles can be deposited throughout your respiratory tract, and a significant fraction of inhaled nanoparticles can deposit in your lungs. From your lungs, they can spread to other organs like your liver, spleen, and brain. They can cross the placenta and may harm an unborn baby in a pregnant woman. The number of research studies and data on these pathways are very limited. The size, shape, and dose (number of particles) of nanoparticles are always relevant. A precise example would be inhalation of diesel soot which causes lung inflammation and stimulates involuntary responses from your cardiovascular system like increasing your heart rate.
2. Another possible route of inhaled nanoparticles into your body is through your olfactory nerve. Nanoparticles can traverse the mucous membrane inside your nose and gain access to your brain via your olfactory nerve.
3. Some studies have linked inhaled nanoparticles with the development of environmental and occupational lung diseases, especially in people who have asthma.
4. Perhaps the most worrisome negative health consequences of nanoparticles are its effects on our DNA (deoxyribonucleic acid), our genetic makeup. Several metal nanoparticles were found out to cause mutations, oxidative DNA damage, DNA strand breaks, and chromosomal aberrations.
5. The present medical and scientific communities and societies are divided concerning the safety of nanoparticles.

Nanoparticles and nanotechnology have the immense potential to impact society as we know it. Unfortunately, engineered nanoparticles have various properties and different effects compared to the same materials made up of bigger particles. The human body’s first encounter and response to these new materials aren’t well established and studied yet. If we could just tell the numerous experts and scientists using nanotechnology to slow down so concerned health authorities and medical doctors will be able to determine if there are immediate and long-term negative health effects of being exposed to these nanoparticles. Are nanoparticles worth the benefits over the risks? We’ll let you decide for now.