Fast Casters – Project Fast Casters – Project UpdateUpdate

March 16, 2006March 16, 2006

Rene ChenRene Chen

Byron HsuByron Hsu

Kimberly KamKimberly Kam

Kelsey VandermeulenKelsey Vandermeulen

Lisa WitmerLisa Witmer

Powder Formulation Powder Formulation ComponentsComponents

PCL: polycaprolactonePCL: polycaprolactone CC66HH1010OO22

PLGA: poly(lactide-co-glycolide)PLGA: poly(lactide-co-glycolide) (C(C66HH88OO44))xx(C(C44HH44OO44))yy

TCP: tricalcium phosphateTCP: tricalcium phosphate CaCa33(PO(PO44))22

HA: hydroxyapatiteHA: hydroxyapatite CaCa55(PO(PO44))33OHOH

Update from Formal Design Update from Formal Design ReviewReview

Modulus ranges for individual Modulus ranges for individual materialsmaterials PCL: 0.5-1 GPaPCL: 0.5-1 GPa PGA: ~8 GPaPGA: ~8 GPa PLA: 2-3 GPaPLA: 2-3 GPa HA: 7-13 GPaHA: 7-13 GPa

Modulus for scaffold structuresModulus for scaffold structures ~0.001 GPa~0.001 GPa

Initial GoalsInitial Goals

Characterize Characterize current current compositioncomposition 30% sucrose30% sucrose 30% lactose30% lactose 20% TCP20% TCP 20% PLGA20% PLGA

Solid structuresSolid structures

Solidworks Test SamplesSolidworks Test Samples

Drew up SolidWorks filesDrew up SolidWorks files Printed tension Printed tension

specimensspecimens

CompressionCompression

TensionTension

Mechanical TestingMechanical Testing Used Yin Lin’s InstronUsed Yin Lin’s Instron Automatic gripsAutomatic grips

Controlled by air Controlled by air pressurepressure

Too high Too high

Manual gripsManual grips Work for our samplesWork for our samples Noisy, inaccurate dataNoisy, inaccurate data

Young’s Modulus: E = Estress/Estrain Young’s Modulus: E = Estress/Estrain = 280 KPa= 280 KPa

Failure Stress = 26.6 KPaFailure Stress = 26.6 KPa Yield Stress = 20.9 KPaYield Stress = 20.9 KPa

Engineering Stress Engineering Stress = force/area = force/area

Engineering Strain Engineering Strain = displacement / = displacement / original lengthoriginal length

Instron Test ResultsInstron Test Results

Future Mechanical Testing Future Mechanical Testing CandidatesCandidates

Look at different methods of testingLook at different methods of testing NanoindentationNanoindentation

Problematic microstructureProblematic microstructure Would need too large of an indenterWould need too large of an indenter

3- or 4- point bending tests3- or 4- point bending tests Will not reduce materials usageWill not reduce materials usage

MicroTester InstronMicroTester Instron Best optionBest option

MicroTester InstronMicroTester InstronMechanical TestingMechanical Testing

MicroTester benefitsMicroTester benefits Smaller load cell Smaller load cell

(10N)(10N) Smaller sample size = Smaller sample size =

less materials and less materials and printing timeprinting time

Automated as Automated as opposed to manualopposed to manual

Made appt. to test Made appt. to test next week (thanks to next week (thanks to Alan Schwartzman)Alan Schwartzman)

SEM ImagingSEM Imaging

X-Ray X-Ray SpectraSpectra

PGLA

Tricalcium Phosphate

Additional ProgressAdditional Progress

Polymer dispersion Polymer dispersion process process Started on PCLStarted on PCL

Received HA orderReceived HA order Placed order for Placed order for

beta-TCPbeta-TCP

Next StepsNext Steps

Test more samplesTest more samples Tension and Tension and

compressioncompression A range of formulations A range of formulations

(using HA)(using HA) SolidWorks test files SolidWorks test files

for MicroTesterfor MicroTester MicroTester testingMicroTester testing Waffle structure in test Waffle structure in test

specimensspecimens

Project TimelineProject Timeline

Questions?Questions?