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Antimicrobial Coatings
By Nikki Buck and
David Brink-Roby
Mentors: Danielle Leiske and Alia Mulder
Background Information
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Background
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What is bioengineering?
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To compare the effectiveness of antimicrobial proteins
and other inhibiting bacterial growth on biomedical
devices.
Applies engineering approaches to problems dealing
with biological systems.
How does this apply to life?
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Bacteria grows on tracheal tubes.
Antimicrobial coatings are needed to prevent
infection.
Equipment and Materials
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Agar
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Pediococcus
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A machine used for sterilization.
Gram Positive
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A medical tube used in hospitals to clean out the air passageways of the
trachea.
Autoclave
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A machine that uses magnets to stir a solution.
Tracheal Tube
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Process of disinfecting a surface.
Stir Plates/ Stir Bars
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A tool used to measure the thickness of a solid.
Sterilization
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A gram negative bacteria found naturally in the human body that causes
stomach sickness.
Caliper
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A gram positive bacteria grown in MRS agar.
E. Coli
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A gelatin compound used to stimulate the growth of bacteria.
Bacterial with thicker cell walls.
Gram Negative
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Bacteria with thinner cell walls.
Procedure
Experiment #1
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Make plates of MRS and McConkey Agar
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Cut equal sized pieces of sterile tracheal tubing
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Soak pieces of tubing in antimicrobial solutions
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Rinse tubing in phosphate buffer
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Place tubing in agar plates
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Incubate the plates overnight
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Measure and record the diameter of kill zones
around each piece of tubing
Experiment #2
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Repeat previous steps but air-dry tracheal tubing
after rinsing in phosphate buffer
Antimicrobial Coatings
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SDS- has a negatively charged head, hydrophobic tail. It is a
surfactant.
DTAB- Has a hydrophobic tail and a hydrophilic head
Nisin- a natural antimicrobial agent used as a lantibacterial
Lysozyme- causes hydrolysis of bacterial cell walls, fights
against bacterial infections
Albumin- Protein manufactured by liver, helps fluid remain in
the blood stream
Phosphate Buffer- a salt or ester of phosphoric acid (a
colorless liquid used in pharmaceuticals) that minimizes change
in the acidity of a solution when an acid or base is added
Analysis
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DTAB and Nisin worked best when killing pediococcus, a gram
positive bacteria
Only high concentration DTAB, and low concentration lysozyme,
killed E. Coli
For Nisin:
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The wet tubing killed more bacteria than the dry
The SDS high and DTAB low concentrations showed a larger kill
zone for the dry tubing than the wet
Albumen did not bond with gram positive bacteria
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Works well when it does
Our second trial had better results
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Low concentration was more effective
Tubing was fully sterilized
Phosphate buffer was used as a control so it did not kill bacteria.
Thank You
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To our mentors, Alia Mulder, Danielle
Leiske, and David Pulitzer for
teaching us the concepts used in our
experiments.
To Dr. Skip Rochefort for leading
us in this great learning adventure
that will change us forever, we will
never forget you!