Polymers: Biomedical
Applications
Bryan Orellana
September 16, 2010
Where can you find uses for polymers?
• Everywhere!
– There seems to be endless
uses for polymers
• Why?
–
–
–
–
–
–
Easier to produce
Biocompatibility
Often cheaper
Designed to mimic
Replacement to old practices
Designed to prevent additional
surgery/trauma to patient
http://www.sharecourseware.org/%28A%28a0C4BeKFywEkAAAAMWYxNTBiZjYtNTUwZS00N2MzLTlkNjQtY2NlOGM2Njc0MDBh8_JtaPeKutpFEQQVUOeBje
6glDI1%29%29/ShowLecture.aspx?ID=454&CatID=1&SubCatID=35
Polymers in Drug Delivery
• Pill coatings
• Rapid dissolving capsules
– Fluid driven
– pH driven
• Degradable delivery vesicles in composite
systems
http://www.pharmainfo.net/raghanaveen/parenteral-controlled-drug-delivery-system
http://www.flickr.com/photos/vancelucas/galleries/72157622318592067
A11/1.4 Poly β-Amino Ester Hydrogel
• Purpose:
– Used as a degradable carrying vessel for bioactive molecules
• Macromer:
– Synthesized by a condensation reaction between Diethylene
Glycol Diacrylate and 3-Morpholinopropyl-amine at 85°C for
16hrs
– Diacrylate : Amine ratio:
2.079gDiacrylate
gAmine
Hydrogel Polymerization
• Hydrogel polymer produced from a mixture of macromer
and DMPA (2,2-dimethoxy-2-phenyl acetophenone), a free
radical initiator dissolved in ethanol
• Solution sandwiched between glass plates (1.5mm thick)
• Photo-polymerized with UV radiation for 5min
• Polymerized gel is washed in ethanol and dried
• Gel is grounded down to obtain particles (average diameters
of 53 - 150 µm and 150-250 µm)
Photo-polymerization
• DMPA cleaves when exposed to UV energy producing
free radical complexes
• Excitation causes complexes to bombard with macromer
• Double bonds break and binds with either another radical
terminating the process or another polymer chain causing
a further chain reaction
http://www.usm.maine.edu/~newton/Chy251_253/Lectures/Free%20Radicals/RadicalPolymerization.GIF
Composite Formation
• Composite consisted of Calcium Sulfate (structural
support) and varying wt. percentage (1% and 10%) of
All/1.4 poly(β-amino ester) hydrogel particles (delivery
component)
• Mixtures are mixed with DI water and placed into a mold.
• Samples are allowed to dry in a 43°C oven for 24hrs
• Sample dimensions:
– Diameter ~4.7mm
– Height ~6.5mm
μ-CT
3-D Image Construction
• Images were contoured and analyzed to produce 3dimensional images
• These images allowed for determination of hydrogel
distribution
The Problem:
Oral Deficiencies
• Oral bone deficiencies are a major Issue!
– High prevalence of periodontitis
– Injury/trauma to jaw bone or teeth
– Other deficiencies from birth defects (i.e. cleft
palate/lip)
http://www.ohiohealth.com/mayo/images/image_popup/fl7_cleft_palate.jpg
http://www.rad.washington.edu/staticpix/mskbook/MandibleFx.gif
The Solution:
Bone Augmentation
•
Performed to increase the amount of bone
to allow for secure implant placement
•
Common procedures:
1)
2)
Alveolar process augmentation of mandible and/or
maxilla
Maxillary sinus augmentation
http://www.dr.agravat.com/images/bone_grafting02.jpg
http://www.drleonedds.com/images/photos/bonegraft1.jpg
http://davidhan.info/yahoo_site_admin/assets/images/bf-Picture4.242141428_std.jpg
Problem with bone graft augmentation
Donor site morbidity
http://scottfross.com/wp-content/uploads/2009/12/bone-graft1.jpg
Bone Augmenation
Example
Courtesy of Scott Price, D.M.D.
Two weeks post-op
Courtesy of Scott Price, D.M.D.
7 months post-op
Courtesy of Scott Price, D.M.D.
Conclusion
• Seemingly endless possibilities with new
advances in polymer chemistry and
medicine
• Being a patient conscience field, new
polymer innovations have helped make
these individuals’ lives easier
What to Remember for Final Exam!!
• What polymerization process was used to
produce the Poly(β-amino ester) hydrogel? Give
a brief explanation of how the process works.
– Photo-polymerization
• DMPA (Photo Initiator) cleaves when exposed to UV energy
producing free radical complexes
• Excitation causes complexes to bombard with macromer
• Double bonds break and binds with either another radical
terminating the process or another polymer chain causing a
further chain reaction
References
•
Borrell, Luisa N., and Natalie D. Crawford. "Social Disparities in
Periodontitis Among United States Adults 1999-2004." Community Dent
Oral Epidemiol 36 (2008): 383-91.
•
Chapple, Iain L.C., Mike R. Milward, and Thomas Dietrich. "The Prevalence
of Inflammatory Periodontitis Is Negatively Associated with Serum
Antioxidant Concentrations." Journal of Nutrition 137 (2007): 657-64.
•
Karadag, Erdener, and Dursun Saraydm. "Swelling Studies of Super Water
Retainer Acrylamide/crotonic Acid Hydrogels Crosslinked by
Trimethylolpropane Triacrylate and 1,4-butanediol Dimethacrylate." Polymer
Bulletin 48 (2002): 299-307.
•
Tonetti, Maurizio S., and Andrea Mombelli. "Early-Onset Periodontitis." Ann
Periodontol 4.1 (1999): 39-52.