PLA Project Final Junior Year

8/2/2019 PLA Project Final Junior Year

http://slidepdf.com/reader/full/pla-project-final-junior-year 1/25

Team Woosah: David Baruela, Samyukta Gade, Jennifer Go,

Alex Hussinger, Austin Schader

Biodegradation of Polylactic

Acid for use in BiodegradableStents



Presentation Overview

PLA

Experiment

Conclusion

Results



A biocompatible material is needed that willbiodegrade within 12 months whilemaintaining structural stability for a

minimum of 6 months and must begeometrically formable into a “stent shape.”

Problem Statement



Selecting PLA

Polylactic acid (PLA) polymers arebiocompatible andbiodegradable

PLA can be manufactured usingmost polymer processingtechniques



Polysaccharides brokendown intomonosaccharide

monomers

Synthesis of PLA ( 1of 3)

Corn isHarvested

(Polysaccharide)

Dextrose

(Monosaccharide)

http://www.google.com/imgres?imgurl=http://thefoodillusion.files.wordpress.com/2010/07/corn.jpg&imgrefurl=http://thefoodillusion.wordpress.com/2010/07/29/understanding-grains-corn-wheat-multi-grain-etc/&h=350&w=470&sz=16&tbnid=FztVytc0LM24CM:&tbnh=96&tbnw=129&prev=/images%3Fq%3Dcorn&zoom=1&q=corn&hl=en&usg=__BDFUs0EYLTlyw4mFJj07nNq3-Rw=&sa=X&ei=hK92TdyEPIigsQP44_W-BA&ved=0CDwQ9QEwBQ



Synthesis of PLA (2 of 3)

Dextrose Fermented to LacticAcid

(via bacterial fermentation)

Lactic Acid

(Monomer)Dextrose

(Monosaccharide)

Lactic Acid

(Monomer)

+

2 Lactic Acid MonomersUndergo Esterificationand Form a CyclicLactide

Cyclic Lactide



Synthesis of PLA (3 of 3)

Cyclic LactideUndergoes Ring-OpeningPolymerization

Cyclic LactidePolylactic Acid

http://upload.wikimedia.org/wikipedia/commons/a/a3/Polylactide_synthesis_v.1.png



Life Cycle Analysis of PLA

Life Stages MaterialsChoice EnergyUse SolidResidues

LiquidResidues

GaseousResidues

Total

Pre-manufacture 2 3 3 3 3 0.7

ProductManufacture

3 2 4 3 3 0.75

Product Delivery 1 1 1 3 2 0.4

Product Use 4 3 4 4 4 0.95

RecyclingDisposal

4 4 4 4 4 1

Total 0.7 0.65 0.8 0.85 0.8 0.76



Eco-Audit of PLA Stents



Hypothesis

Based on previous research involving thedegradation of PLA sutures in porcinemodels, we believe that our PLA sampleswould not show measurable signs of

degradation over the course of one week.



Unresolved Questions

Will PLA degradequickly enough if at

all?

How does PLA reactin different bodilyconditions?



Fountain pumps were usedto simulate the bloodsystem.

Different pHs were used to

cover the range of pH inthe human body.

Different diameters simulatedifferent artery sizes in

the body.

Experimental Overview



Experimental Overview



It worked!

Testing and Results



Minitab Analysis:

Anova was performed to determine cause andeffect interactions for Concentration,Flow/Pressure, and Time

Overview of Analysis



Chemistry of Degradation

Hydrolysis Reaction

Breaking ester bonds = *



Chemistry of Degradation (cont.)



Chemistry of Degradation (cont.)

Le Châtelier's Principle



3 Stages of PLA Degradation

Stage 1:◦ M.W. of PLA samples still high, but

degrading

Stage 2:◦ M.W. of polymer decreases◦ Polymer chain ends become more

reactive◦ Degradation rate increases

Stage 3:◦ Interactions between PLA and water

increases◦ PLA starts to absorb water◦

M.W. of PLA further decreases, soonbecomes soluble



SEM Micrographs of PLA SampleDegradation

Untreated PLASample



SEM Micrographs of PLASample Degradation

PLA sample after 1 week of degradation in basic solution, 1inch pipe.

PLA sample after 1 week of degradation in basic solution, ½inch pipe.



SEM Micrographs of PLASample Degradation

PLA sample after 1 week of

degradation in acidic solution, 1

inch pipe.

PLA sample after 1 week of

degradation in acidic solution, ½

inch pipe.



Discussion

Our hypothesis was incorrect



Conclusions



http://www.google.com/imgres?imgurl=http://www.cedars-sinai.edu/International-Patients/Spanish/Tratamientos-y-Programas/Corazon/Images/472679_stent-32648.jpg&imgrefurl=http://www.cedars-sinai.edu/Patients/Programs-and-Services/Heart-Institute/Treatment-Programs/Angioplasty-and-Stenting.aspx&usg=__xeL6utJc6eEtOo1VyZelpAW_cRw=&h=307&w=525&sz=34&hl=en&start=0&zoom=1&tbnid=7uCduFWloaCGXM:&tbnh=82&tbnw=140&ei=2_RaTYrEKIzmsQOaq8iYCg&prev=/images%3Fq%3Dstent%26um%3D1%26hl%3Den%26sa%3DN%26biw%3D935%26bih%3D530%26tbs%3Disch:1&um=1&itbs=1&iact=hc&vpx=368&vpy=239&dur=2187&hovh=172&hovw=294&tx=180&ty=107&oei=2_RaTYrEKIzmsQOaq8iYCg&page=1&ndsp=16&ved=1t:429,r:8,s:0

http://www.google.com/imgres?imgurl=http://bestdealpromo.com/blog/wp-content/uploads/2010/08/recycling-symbol-7-other.gif&imgrefurl=http://bestdealpromo.com/blog/2010/09/recycling-plastics-symbols/&usg=__v1n_T-S3QjsgQICxy_iqEgXkupY=&h=130&w=100&sz=4&hl=en&start=0&zoom=1&tbnid=8_Xs2wf8K8kyGM:&tbnh=104&tbnw=80&ei=h_RaTaawJpCosAO97vWhCg&prev=/images%3Fq%3Drecycling%2Bsymbol%2B7%26um%3D1%26hl%3Den%26sa%3DN%26biw%3D935%26bih%3D530%26tbs%3Disch:1&um=1&itbs=1&iact=rc&dur=110&oei=h_RaTaawJpCosAO97vWhCg&page=1&ndsp=18&ved=1t:429,r:5,s:0&tx=39&ty=59

•http://www.google.com/imgres?imgurl=http://www.biojobblog.com/uploads/image/STENT%2520CLOSED.JPG&imgrefurl=http://www.biojobblog.com/tags/layoffs/&usg=__JySLuyZENzOJMkMVaQrYZq1RCTM=&h=480&w=640&sz=99&hl=en&start=0&zoom=1&tbnid=mEuFkq2yPe2MhM:&tbnh=124&tbnw=165&ei=4fVaTYjkNofQsAOTpPyNCg&prev=/images%3Fq%3Dstent%26um%3D1%26hl%3Den%26biw%3D1423%26bih%3D711%26addh%3D36%26output%3Dimages_json%26tbs%3Disch:1&um=1&itbs=1&iact=hc&vpx=441&vpy=406&dur=250&hovh=194&hovw=259&tx=82&ty=222&oei=1PdaTdijPJKgsQP_9a2RCg&page=1&ndsp=32&ved=1t:429,r:26,s:0

•https://www.myhealth.va.gov/mhv-portal-web/ShowBinary/BEA%20Repository/images/cholersteral.gif

•http://www.google.com/imgres?imgurl=https://reader009.{domain}/reader009/html5/0505/5aed797547173/5aed798388242.jpg&imgrefurl=http://www.cartoonstock.com/directory/h/heart_health.asp&usg=__jDmjvASmXr9QhBHvTXEM2OvJ-Ms=&h=382&w=400&sz=35&hl=en&start=69&zoom=1&tbnid=RLQpBTB_-0WniM:&tbnh=111&tbnw=116&ei=RvlaTfmmHIG4sAO-vrihCg&prev=/images%3Fq%3Dheart%2Bdisease%2Bcartoon%26um%3D1%26hl%3Den%26sa%3DN%26biw%3D948%26bih%3D530%26tbs%3Disch:10%2C1608&um=1&itbs=1&iact=hc&vpx=679&vpy=135&dur=15&hovh=219&hovw=230&tx=180&ty=123&oei=PvlaTabaAo7GsAOQqLyVCQ&page=5&ndsp=16&ved=1t:429,r:4,s:69&biw=948&bih=530

•http://www.ptca.org/forumtopics/topic20060607.html

•http://www.google.com/imgres?imgurl=http://pharmaclips.files.wordpress.com/2009/12/coronary_stents.jpg&imgrefurl=http://pharmaclips.wordpress.com/&usg=__0pOVbs7bUDcI7hDZ2q9rW6KDlBg=&h=300&w=400&sz=25&hl=en&start=15&zoom=1&tbnid=UleLaPkOM_MSwM:&tbnh=153&tbnw=192&ei=FP9aTfrVLZS0sAOU0aScCg&prev=/images%3Fq%3Dstent%26um%3D1%26hl%3Den%26sa%3DN%26biw%3D935%26bih%3D496%26tbs%3Disch:10%2C965&um=1&itbs=1&iact=hc&vpx=650&vpy=94&dur=1219&hovh=194&hovw=259&tx=163&ty=103&oei=C_9aTdjNA4mosQObyq2dCg&page=3&ndsp=8&ved=1t:429,r:7,s:15&biw=935&bih=496

•[email protected] 805 756 2422

References

http://var/www/apps/conversion/Local%20Settings/Temp/&um=1&itbs=1&iact=hc&vpx=368&vpy=239&dur=2187&hovh=172&hovw=294&tx=180&ty=107&oei=2_RaTYrEKIzmsQOaq8iYCg&page=1&ndsp=16&ved=1t:429,r:8,s:0


http://var/www/apps/conversion/Local%20Settings/Temp/itbs=1&iact=rc&dur=110&oei=h_RaTaawJpCosAO97vWhCg&page=1&ndsp=18&ved=1t:429,r:5,s:0&tx=39&ty=59

mailto:[email protected]









PLA Project Final Junior Year

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