Download Approximately 800000 people experience a stroke every year, the

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Solving a Blood Clotting Issue
Prevent a Stroke Activity
Approximately 800,000 people experience a stroke every year, the leading cause of adult-onset
disability in the United States. Stroke, also termed brain attack, is a loss of brain function due to the
interruption of the blood supply to the brain. Without adequate blood supply, or ischemia, the affected
region of the brain is starved of nutrients, and can die. The human brain has over a hundred-billion
neurons and different functions are localized to different regions of the brain. Despite the large
number of neurons, the slightest loss of brain tissue can result in catastrophic disabilities.
(Demonstration with human brain - if accessible. Point out the different regions of the brain and their
corresponding functions. Ask what would occur if certain portions of the brain atrophied and how
difficult it would be to go through life dependent on others. Allow students to touch brain for texture
and consistency if possible).
Ischemic stroke can occur due to a blockage in the blood vessel as a result of a formed blood clot
(thrombosis), or a blood clot or plaque that migrated to block blood flow (embolism). Stroke can also
be due to hemorrhage, hemorrhagic stroke, blood flowing out of the vessels and unable to reach to the
other side. Ischemic stroke is far more common, occurring approximately 90% of all strokes.
Polymer
A polymer is a large molecule made up of repeating units covalently bound to one another. The
repeating units are termed monomers, which is composed of a collection of atoms. Polymerization is
the process of covalently linking together monomers to form the long chain polymer, with carbon,
oxygen, nitrogen, and silicone commonly found in the backbone. The structure of the monomer and its
connectivity in making the polymer determine the overall properties of the polymer. Separate polymer
chains can also bind to one another through connections known as cross-links. Cross-links hold
polymers together, reducing the ability for polymers to slide past one another, effectively altering its
physical properties.
Polymers are both naturally and synthetically created. Synthetic polymers are both diverse and
widespread, and include nylon, polystyrene, and Teflon. In humans, polymers are paramount for life
processes and include polysaccharides (polymers of sugars), polypeptides (polymers of amino acids),
and polynucleic acids (polymers of nucleic acids).
Blood clot/coagulation
Blood is a fluid composed of plasma, blood cells, platelets, and a variety of dissolved proteins, sugars,
and minerals. Blood is essential for the delivery of nutrients and removal of wastes for each and every
cell of the body. Blood is confined to the blood vessels of the body, pushed through the system by the
heart. Loss of blood, even through a small cut, can lead to death if not properly healed or treated. A
blood clot is formed at the site of a damaged blood vessel to stop bleeding.
The process of forming a blood clot is coagulation. Damage to a blood vessel is sensed by platelets,
which immediately begin to bind to the damaged tissue and plug the opening. The damage is also
sensed by protein molecules floating by in the blood, called clotting or coagulation factors. Through a
complex cascade of reactions involving dozens of molecules and proteins, fibrinogen, an important
blood-clotting protein, is recruited to the site of damage and converted to fibrin. Fibrin is then
polymerized to form a meshwork in conjunction with the platelets to form the blood clot. Abnormalities
in this process can lead to severe complications; excessive clotting can result in heart attack and
stroke, whereas less effective clotting can result in hemorrhage.
Biomedical engineers and scientists are working tireless to develop therapeutic methods to unblock
vessels that lead to ischemic stroke. Investigators often conduct experiments with models before
testing their treatments on humans. (Teacher to present blocked clear tubing as a model). In this
activity, your goal will be to determine a method to unclog the tubing without mechanical force. Just as
scientists first studied the blood clotting process before developing a therapy, you will first experiment
with the polymerization of the white clog in the tube.
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Materials
Each group needs:

4 Paper cups

4 Wooden stirrers

1 Petri dish

White glue (60 mL)

4% Borax solution (50 mL)

Graduated cylinder (50 mL)

1 M HCl

1M NaOH

Enzyme solution

Water

5% NaCl solution

5% Glucose solution

Detergent
Procedure
1. Label the four paper cups.
2. Fill graduated cylinder with 15ml of water and pour into paper cup 1. Mark the level of the water in
the cup. Pour out the water. Mark the same level in each of the three remaining cups.
3. For each paper cup trial, fill the white glue up to the line on the paper cup. Add 30mL of water and
10mL of borax
4. Using your chosen solutions, attempt to find a cure to blood clotting. Determine the most effective
way to break up a clot.
5. Stir well and once polymer is formed, knead for several minutes and continue to observe.
Data (5marks)
Table 1:
Polymer
White
glue
Water +
Borax
Polymer Trial 1
To line
(15 ml)
30 + 1 tsp
Polymer Trial 2
To line
(15 ml)
30 + 1 tsp
Polymer Trial 3
To line
(15 ml)
30 + 1 tsp
Polymer Trial 4
To line
(15 ml)
30 + 1 tsp
Important Notes:
Solution
to Test
Clot
Observations
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Analysis of Results
Is a blood clot a polymer? Is it a protein? Explain the structure of a blood clot and how it is formed in the
body. (Include the clotting cascade in your answer) (8marks)
What are two causes of stroke? (2marks)
If a blood vessel were clogged with a polyvinyl acetate polymer, would the solution your group found be
applicable? Explain your answer. (2marks)
If you were developing a cure for actual stroke patients, what would you need to do before trying it on actual
stroke patients? (3marks)