The Quest for Artificial Blood
Job Title: Lead Research Scientist
Scenario: Scientists have been searching for an all purpose artificial blood for a very long time.
They have successfully creating blood substitutes that can mimic some of the properties of real
blood, such as carry oxygen throughout the circulatory system, however they have not been able
to create a substitute that can be used in place of real blood in all situations. The two most
common types of artificial blood are HBOCs (hemoglobin-based oxygen carriers) and PFCs
(perflourocarbons). As of June 2008 there were no haemoglobin-based oxygen carriers or
perfluorocarbon emulsions available for commercial use in North America or Europe. The only
countries where these products are available for general use are South Africa and Russia. This is
because they significantly increase the risk of death and heart attack (Wikipedia, 2011).
The company that you work for, Hemo-Technologies, is on the verge of announcing the
development of the first complete blood substitute. They claim that this new artificial blood
meets all of the requirements of an ideal blood substitute; it transports oxygen and carbon dioxide
as well as other essentials components such as various proteins, it helps to distribute body heat
throughout the body, it removes waste from the body, it is able to provide blood clotting to
wounds, and it is able to perform immune system functions. However, the last test that remains is
to determine if this new substitute is able to effectively maintain a pH of 7.4 as real blood does.
In order to do this, the blood must be able to act as an effective buffer when carbon dioxide
produced during cellular respiration creates carbonic acid in the blood. If carbonic acid lowers
the blood pH too drastically there can be serious or fatal consequences.
As the lead scientist, your research team is looking to you help them to determine the buffering
ability of the new artificial blood.
You remember that you have an acid/base indicator in your lab called Methyl Red that you
could use in this lab.
You goal is to determine whether or not the artificial blood will be an
effective product for Hemo-Technologies to market.
Teacher Notes
Preparation of “REAL BLOOD”
Borax Buffer Solution (Sodium tetraborate buffer - 0.1M NaOH)
i) Add 2g NaOH, 11.75g Borax to 500 ml distilled water, make sure all powders are
dissolved completely.
ii) Use 0.2 micron filter membrane to filter. pH should be around 8.2.
Preparation of “ARTIFICIAL BLOOD”
0.1M NaOH Solution
i) Add 2g NaOH to 500 ml of water.
ii) Stir until NaOH is completely dissolved.
Preparation of “CARBONIC ACID”
1.0M H2SO4 (Sulfuric Acid)
Methyl Red Indicator
Helpful Hints
- use 20ml of blood or blood substitute with 20 drops of methyl red indicator
- Drop by drop titrations of carbonic acid are sufficient, you do not need to measure exact
amounts with burettes
- Methyl Red is an acid/base indicator which is yellow at a pH of 6.2 and higher, and is red at a
pH of 4.4 and lower.
- You are free to use the Vernier pH probes for a more accurate, graphed approach to your
conclusion