Aim:

Student learning outcomes:

• Understand the different ways in which nanoparticles may enter the cell membrane.

• Consider the implications of having inorganic molecules inside the cell.

• Understand that toxicity may be built up over time from exposure to inorganic nanoparticles. 

 

Background information:

The biological cells are made up of lipid bilayer, a barrier that protects the cell from any external harmful molecules that may enter the cell. With the increase of nanotechnology, the amount of interactions we have with inorganic small nanoparticles are getting greater. As a result, we are now facing potential inorganic compounds entering our body that have never been seen before or closely studied. 

It has been demonstrated that nanoparticles could enter the cell membrane via diffusion, endocytosis or exocytosis without being involved with specific receptor mediated interactions. As a result, there is a potential for toxicity to be built up in cells which are exposed to different types of nanoparticles. These particles are often harmless to an individual but with much exposure the toxicity will eventually build up and can damage the cell.

 

In order to demonstrate the build-up of nanoparticles in a cell students will be conducting the following activity:

1. Using a large cloth preferably a size above 2x2m and cut tiny 7cm holes in a cross shape and then open those as shown in the pictures (Try keeping the holes towards the centre of the cloth).

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2.  Take A4 sheets of paper (preferably from the recycling bin so we do not waste

paper) and scrunch them up into tiny balls. Use one A4 sheets of paper for the first

ball, two A4 for the second ball, three A4 for the third and six A4 papers for the last

ball. The picture is an example of how it will look like when completed.

(Alternatives: Styrofoam or plasticine balls)

3. Nominate 4 students to hold each corner of the cloth, below their waist so the

centre of the cloth is lower than the outer corners creating a lowered level centre

so the balls may fall into the hole.

4. Split into 4 groups with each group having one kind of ball. For example, group one

will only use the one A4 paper ball and group two will use two etc. Each group should have approximately 20 paper balls.

5. Strictly drop the ball from any side and see which ones gets through the holes.

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Results

1. Fill out the table below

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   2. Graph your tabulated data. Clearly label your axes and include a meaningful title.

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Discussion

   3. Referring to your data describe the trend observed of number of balls passing through the holes in the fabric.

Should observe the smaller the ball the larger the number of them passing through the holes in the fabric

  4. Do your results support the idea that cell toxicity can occur with increased exposure to nanoparticles? Explain.

The results show that the smaller particles more readily passing through holes in the fabric (students should refer to data) and given that nanoparticles are very small and so would pass through the cell membrane into the cell more easily, you would expect with increased exposure to nanoparticles would lead to increased cell toxicity. 

  5. How might inhaled nanoparticles affect health in people and animals? 

Inhaled nanoparticles can be deposited throughout the human respiratory tract, and an important fraction of inhaled nanoparticles deposit in the lungs. Nanoparticles can potentially move from the lungs to the blood circulatory system to other organs such as the brain, the liver, the spleen and possibly the foetus in pregnant women. They may do this as there is a large blood supply in the nasal cavity and surrounding alveoli in lungs and given their small size are able to easily enter tissue and circulatory system.

  6. Some technologies incorporate nanoparticles to clean up industrial contaminants and spills by spraying them into the environment or flushing them down drains. How might this process potentially impact organisms or drinking water?

If nanoparticles enter waterways aquatic organisms such as fish would accumulate nanoparticles in their systems as water moves across fish gills is taken in via their mouths. Could discuss aquatic plants and other marine life. Additionally, affected drinking water impacts humans that drink it and garden as people use it to water their plants.

  7. Research using the internet 2 benefits and 2 problems with the increasing use of nanoparticles in science. https://academic.oup.com/bioscience/article/68/4/241/4915956

Benefits

A nanoparticle may conduct electricity better, become stronger, or become capable of catalysing reactions. These traits constitute an amazing toolbox when it comes to environmental problem solving. Nanoparticles are being used to clean up soil and groundwater contamination, oil spills, can be used to transform, detoxify, and immobilize contaminants such as polychlorinated biphenyls (PCBs). Nanoparticles are also being used to strengthen existing materials. For example, wind turbine blades can be coated in an epoxy containing carbon nanotubes to reduce the weight of the blades and increase their durability. This increases energy production.

 

Problems

Silver nanoparticles particles deposited in water ways may be ingested by aquatic organisms and bioaccumulate in animals further up the food chain.

Impacts of silver and copper nanoparticles on soil communities. These communities are composed of the plants, fungi, bacteria, insects, and earthworms that maintain the structural and chemical composition of the soil. Through the direct impacts of nanoparticles on soil organisms but also cascading effects that have the potential to change entire communities.

  8. Find out about the different ways nanoparticles can enter cells. Draw up a table to present your information. The following links may help.

http://sustainable-nano.com/2014/08/19/how-do-nanoparticles-enter-cells/

https://pdfs.semanticscholar.org/e57f/b002105111c54714f3bd4ffe564f0212a665.pdf

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