Transcript Collagen Self-Assembly Mechanisms

Collagen Fibrillogenesis
Using Voltage to Optimize
Protein Growth
Mary Beth Bird
Mentor: Ramana Pidaparti, PhD.
Mechanical Engineering Department
July 23, 2007
Goals of Project
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To trigger self-assembly mechanisms in collagen
To establish an experimental setup that will
support fibrillogenesis
To monitor and alter variables in experiment to
determine the best environmental conditions for
fibrillogenesis
To replicate experimental data in computational
modeling derived from research data
Background on Collagen
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Most common form of protein in the human body
Triple helical molecule consisting of 3 alpha
chains of amino acids
There are 13 different kinds of collagen, Type I –
XIII
Cross-linking during fibrillogenesis causes
unique properties amongst the different types
Collagen can be found in all connective tissues;
ie. bones, tissues, cartilage, ….
The Original Idea
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Use metal substrate as a voltage conductor
coated with SDS (Sodium Dodecylsulfate)
Layer with a 1-2cm sq of collagen in an acidic
solution
Apply voltage across metal conductor
Monitor growth formation using electron
microscope
Variables: pH, time, voltage, concentration of
collagen solution
Problems Encountered
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Type of substrate
Determining collagen Type and form to be used
Use of SDS (Sodium Dodecylsulfate, ionic surfactant)
Use of Hydroxylapatite (mineral)
Application of voltage using Corrosion Data Program
Physical experimental setup
Ability to monitor pH and temperature
Method of examining collagen formation
Method of quantifying and understanding data
Ability to confirm presence of fibrils
Prevention of corrosion
Images from the Lab
Concerns
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Corrosion
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Substrate Surface
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How can we prevent corrosion?
Alter voltage? Alter pH using NaOH? Alter substrate?
How can we improve the surface of the substrate to
prevent false images?
Analyzing Images
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How do we confirm presence of fibrils?
What is the best way to take images?
SEM, AFM, Optical Microscope
Future of the Project
Continue to refine methods to decrease
the number of experimental errors
 Control and alter experimental variables
ie. pH, temperature, voltage
 Form a better method to quantify and
examine data
 Expand project to include DNA
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Acknowledgements
Project Team Members:
- Sumeet Lall, HSURP
- Dr. Ramana Pidaparti
Mechanical Engineering Dept., VCU
Dr. Gary Bowlin
Biomedical Engineering Dept., VCU
- Dr. Peter C. Moon
School of Dentistry, VCU
- Eddie McCumiskey, Grad Student NanoMan Lab
Mechanical Engineering Dept., VCU
- Dr. Stephen Fong’s Lab
Chemical and Life Sciences Engineering Dept., VCU
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References
1. Encyclopedia of Human Biology. 2nd ed. San Diego, CA:
Academic Press; 1997.
2. Du C, Cui F, Zhang W, Feng Q, Zhu X, de Groot K.
Formation of calcium phosphate/collagen composites
through mineralization of collagen matrix. Journal of
Biomedical Materials Research [serial online].
2000;50:May 31, 2007.
3. Sini P, Denti A, Tira M, Balduini C. Role of decorin on in
vitro fibrillogenesis of type I collagen. Glycoconjugate
Journal. 1997;14:871-874.