Scaffold Degradation Effects on Eukaryotes

Sam PattonGrade 9

Central Catholic High School

Scaffold Degradation

• Scaffold – a frame used for supporting a larger structure. In tissue engineering, a temporary, biodegradable frame for supporting tissues

Replacing damaged or diseased tissue with healthy tissue, specific for the needs of each individual patient

What is Tissue Engineering?

Spinal Cord

Jaw

Limb

The Ultimate Goal of Tissue Engineering is

Complete Tissue Regeneration of the Any

Body Part Heart

Stomach

Liver

Matrix Culture Implant

Cells can be taken from the patient, more reliable this

way due to cell recognition

How Tissue Repair Works

Scaffold Degradation• If the scaffold has unwanted effects on any internal

organs or the blood stream, then the patient may regress

Scaffold Degradation

• PVA Scaffolds are natural scaffolds made with polyvinyl alcohol, so that they have little effect on the body

Polyvinyl Alcohol

• Natural polymer made from polyvinyl acetate, highly soluble in water, assumed to not harm people

Yeast• Saccharomyces cerevisiae, a commonly used

model, similar to human epithelial cells in biochemistry

Saccharomycescerevisiae

Purpose

• To test the effects of PVA degradation products on

yeast survivorship

Hypotheses

• Null Hypothesis –• The Biodegraded PVA scaffolds will not have a

significant effect on the growth of yeast colonies

• Alternative Hypothesis -The Biodegraded PVA Scaffolds will have a

significant effect on the growth of yeast colonies.

Materials• Stirrer bars• Test tubes• 24 YEPD agar plates

(1% yeast extract, 2% peptone, 2% glucose (dextrose), 1.5% agar)

• LB media (0.5% yeast extract, 1% tryptone, 1% sodium chloride)

• PVA Scaffolds• Vortex

• Pipets• Large flasks

and beakers• Distilled water• Incubator• Electronic

metric scale• Ethanol

Create Scaffolds Procedure1. The PVA Scaffold was cut up so that it

weighed exactly one gram.2. The one gram was cut into very small pieces.3. The pieces were put into a 50mL conical tube

with 9mL of sterile water4. It was incubated until the scaffold had

degraded.5. The mixture was sterilized by adding ethanol to make a 5% sterilized scaffold

mixture (the mixture wouldn't go through a sterile filter)

Concentrations of Scaffold Chart

Column1 Column2 Column3 Column4 Column5

Sterile Water 9.9mL 9.88mL 9.7mL 7.9mL

5% Degraded Scaffold Mixture 0mL 20uL .2mL 2mL

Yeast 0.1mL 0.1mL 0.1mL 0.1mL

Total Volume 10mL 10mL 10mL 10mL

Concentration 0% 0.01% 0.10% 1%

Creating and Culturing the Plates Procedure

1. 100uL aliquots from each tube pipetted onto YEPD agar plates

2. The plates were incubated for 48 hours at 30 degrees Celsius

3. The resulting colonies were visually counted, each colony was assumed to have arisen from one cell

P-Value: 0.39

020406080

100120140160

Control 0.01% 0.10% 1% 0%

Num

ber o

f Col

onie

s

Concentration of Scaffolds

PVA Scaffold Effects on Yeast Survivorship

P

Conclusion

• The null hypothesis was accepted, suggesting that the degradation of PVA scaffolds does not affect yeast

survivorship

Limitations• Only yeast was used, not

other specimens• Only PVA scaffolds were

used, not any others, such as TCP or PGLA

• Spread plating was not synchronized (human error)

• Ethanol for sterilization may have killed some yeast

• Only one exposure time and one type of exposure

• Other scaffolds other than PVA, such as PGLA and TCP

• Use different models (E. coli, staph, etc.)

• More concentrations and replicates

• Varied exposure times and types of exposures

• Synergistic effects

Extensions

References• http://redstaryeast.com/science-yeast/yeast-

experiments/• http://study.com/academy/lesson/extracellular-matrix-

function-components-definition.html• http://www.ncbi.nlm.nih.gov/pubmed/23565688• http://www.britannica.com/science/polyvinyl-alcohol

Anova