1. Fast Casters – Initial Prototype April 6th, 2006
Rene Chen
Byron Hsu
Kimberly Kam
Kelsey Vandermeulen
Lisa Witmer

2. Update Printed new samples Mechanical Testing SEM Analysis Sintering
Tension
Compression
SEM Analysis
Sintering
Prototype

3. Avg. Particle size (micron)
Formulations
Variables: particle size of...
Fluka TCP vs. MGH TCP
Sucrose vs. 10x Confectioners Powder Sugar
Powders
Avg. Particle size (micron)
TCP (Fluka)
2-3
TCP (MGH)
12-15
Polymer (PCL)
30-40
Sucrose
Confectioners

4. Formulations PCL: polycaprolactone TCP: tricalcium phosphate
Formulation 1 (Blue)
wt %
vol %
PCL 20 32
TCP (MGH) 16
Lactose 30 25
Sucrose 28
Formulation 2 (Red)
wt %
vol %
PCL 20 34
TCP (Fluka) 12
Lactose 30 27
10X confectioner 28
Formulation 3 (Black)
wt %
vol %
PCL 20 32
TCP (MGH) 16
Lactose 30 25
10X confectioner 26
PCL: polycaprolactone
TCP: tricalcium phosphate

5. New Sample Dimensions Dog bones for tension test: 5mm x 5mm x 20 mm
Cylinders for Compression test:
15mm x 15mm

6. Mechanical Testing - Purpose
Mechanical modulus in the range of hard (10–1,500 MPa) or soft tissues (0.4–350 MPa) needed to prevent new tissue failure due to excessive deformation.
Scaffold mechanical properties theoretical maximum set by bulk material
Hollister, Scott. Porous scaffold design for tissue engineering. Nature materials. Vol 4. July 2005

7. Mechanical Testing 0.05 mm/s pull rate data collection at 80Hz
Load cell: 10N for tension
2000N for compression

8. Mechanical Testing - Results
BLUE: TCP (Serdy), sucrose
RED: TCP (Fluka), 10x confectioner’s sugar
BLACK: TCP (Serdy), 10x confectioner’s sugar

9. Mechanical Testing - Results
BLUE: TCP (Serdy), sucrose
RED: TCP (Fluka), 10x confectioner’s sugar
BLACK: TCP (Serdy), 10x confectioner’s sugar

10. SEM Analysis - Results
SEM Analysis - Results
TCP: Ca5(PO4)3OH

11. SEM Analysis - Results
SEM Analysis - Results
Ca5(PO4)3OH + Polymer

12. SEM Analysis - Results
Necking in polymer matrix

13. Sintering Purpose: create a stiffer porous structure
Polymer is too soft
Increase TCP concentration
Idea: sinter a TCP + polymer/sugar mixture to create porosity with strength

14. Sintering Techniques Densification Coarsening Higher temperature
Center approach each other (Shrinkage)
Coarsening
Lower temperature
High Strength + Porosity maintained!

15. Sintering Test

16. Sintering Result
Sample
Vol. Shrinkage (%) 1
78.19 2
75.23

17. Initial Prototype Formulation
Smaller particles  weaker structure
Sintering
Higher volume percent TCP
Experiment with heating times and rates

18. Project Timeline

19. Questions?