Dubai: Nanoparticles, or tiny particles, can be found all around us – some existing in nature, others man-made. They are at the forefront of materials science and have a variety of uses. Due to their sub-microscopic size, they have unique characteristics and are applied in a variety of fields.
Lately, there have been concerns about their use in the food industry and whether they seep into the gut, making them toxic.
Although studies on this are still at an early stage, research has shown that some nanoparticles can be absorbed by the body, making them hazardous to health.
Here is an overview of nanoparticles.
What are nanoparticles?
Nanoparticles, as their name suggests, are particles ranging in size from 1 to 100 nanometers (compare that to a human hair, which is about 80,000 nanometers thick). Undetectable to the naked eye, most of them consist of only a few hundred atoms.
Do they occur naturally or are they manufactured?
In nature, there are several nanoparticles. A spider’s silk is strong due to nanoproteins and a gecko’s legs are sticky due to nanohairs.
They can, however, be created, and because they are so small, they offer unique features that make them appealing to a wide range of businesses.
Nanometer-scale materials have been produced for several decades. Today, the production capabilities of purpose-built nanomaterials have increased dramatically.
How are they made?
Specific synthesis methods are used to produce various nanoparticles, coatings or composites.
Two basic strategies are used to produce nanoparticles – top-down and bottom-up.
Top-down refers to the mechanical crushing of the source material using a grinding process.
In the bottom-up strategy, structures are built by chemical processes.
What are nanoparticles used for?
The small size of nanoparticles and large surface-to-volume ratios mean that they can be used for a wide range of applications. They can be mixed with other materials to form composite materials with improved properties.
Nanosilver is used to coat medical breathing tubes and bandages, and it can transfer cancer treatments directly into tumor cells. Nanoparticles could direct pesticides to specific sections of a plant or regulate the flow of nutrients from fertilizers.
They can also be used for more mundane purposes. Cosmetics and foods contain synthetic nanoparticles. Band-aids, exercise leggings and yoga mats contain nanosilver, which is believed to have antibacterial characteristics.
Nanoparticulate materials are used in some sunscreens, paints and cosmetics.
Are nanoparticles safe?
Scientists are concerned that synthetic nanoparticles could be released into the environment when household items are washed or recycled. This, in turn, penetrates the ground and the sea. Synthetic plastic nanoparticles have been found in the ocean and in the ice of both poles. Unlike chemical compounds, they cannot be dissolved.
What about food? Should we be worried?
In the food industry, nanotechnology can be used to improve the quality, shelf life, safety and nutritional benefits of food. Some nanomaterials are used in packaging and antimicrobial treatments for disinfection in food manufacturing plants.
The use of man-made nanoparticles in foods, such as those used as delivery systems for colors, flavors, preservatives and nutrients, has raised some concerns, according to the Nature website. Research has found that many nanoparticles are unlikely to cause adverse effects on human health, but there is evidence that some of them may have harmful effects and future studies are needed.
What types of nanoparticles are found in food?
Nanoparticles in food can be divided according to their composition – organic or inorganic.
Inorganic materials like silver, iron oxide, titanium dioxide, silicon dioxide or zinc oxide are some types of nanoparticles used in food. They also vary in their tendency to dissolve under different solution conditions.
They are used in a variety of applications in the food industry – as antimicrobial agents in food and packaging materials. There is little information on the potential toxicity of silver nanoparticles ingested with food. However, several animal studies have reported that silver nanoparticles can accumulate in various organs after ingestion, including the liver, kidneys, spleen, stomach and small intestine, according to Nature.
Titanium dioxide nanoparticles
These particles are used as functional ingredients in certain foods to provide optical properties such as increased lightness and brightness. Chewing a piece of gum can lead to an intake of 1.5 to 5.1 mg of titanium dioxide nanoparticles. The amount of these particles consumed was 2 to 4 times higher in children than in adults, probably because many products consumed by children had some of the highest levels of this nanoparticle.
Silicon dioxide nanoparticles
These nanoparticles are added to some powdered foods to improve flow properties. Research has suggested that silicon dioxide nanoparticles accumulate in the liver to levels that could lead to adverse effects.
These are mainly composed of organic substances, such as lipids, proteins or carbohydrates. In general, they are believed to be less toxic than the inorganic ones.
These are widely present in many food products, such as soft drinks and fruit juices. Different types of lipid nanoparticles can be present in food, including oil droplets and fat crystals.
Casein micelles, which are tiny clumps of casein molecules and calcium phosphate ions found in cow’s milk and other dairy products, are the most common protein nanoparticles found in meals. The potential toxicity of this form of nanoparticle is of little concern, as it has been widely ingested by humans for centuries.
The difficulties related to the search for organic nanoparticles in complex biological matrices have meant that few studies have been carried out. Further research is needed on the fate and toxicity of organic nanoparticles after absorption.