april 5, 2007 initial prototype presentation p e m pemplant co. maricela delgadillo kay furman...
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April 5, 2007Initial Prototype Presentation
PE
M
PemPlant Co.
Maricela DelgadilloKay FurmanYushan Kim
Overview
• Update▪ Methylene blue staining: more results▪ Contact angle results▪ Mechanical force probe update
• Initial prototype• Future characterization steps
Contact Angle Measurements
• Samples Tested▪ Bare Ti, glass, 2.0/2.0
crosslinked, 3.0/3.0 crosslinked and uncrosslinked
• DI water used as Solvent• Average of three
measurements
Reference Data
• For 3.0/3.0 system▪ Contact: 61▪ Receding: <10
• For 2.0/2.0 system▪ Contact: <10
Yang, S. Y.; Mendelsohn, J. D.; Rubner, M. F. Biomacromolecules. 2003, 4 (4), 987-94
Results for Glass System
• Glass▪ Contact: 83.7º▪ Receding: 73º
• 2.0/2.0 Crosslinked▪ 10.6º
• 3.0/3.0 Crosslinked▪ 29.45º
• 3.0/3.0 Uncrosslinked▪ 12.4º
2.0/2.0 x-linked
Glass
Results for Ti System
• Bare Ti▪ 38.3º
• 2.0/2.0 Crosslinked▪ 31.35º
• 3.0/3.0 Crosslinked▪ 80.2º
• 3.0/3.0 Uncrosslinked▪ 67.4º
2.0/2.0 x-linked
3.0/3.0 un x-linked
Results
• Bare Ti Lit review measures about 100º▪ Lower value may be due to surface
roughness• Significant increase in contact angle
measurements on Ti surfaces as compared to Glass▪ Polymer film on Ti results in a more
hydrophobic surface▪ Glass system results in a more hydrophillic
surface
Initial Prototype
• Cleaning: acetone wipe, ethanol sonication
• Layers:▪ Polyanion (PAA) 15min,
rinse 3x (2, 1, 1 min)▪ Polycation 15 min,
rinse 3x (2, 1, 1 min)
Polycation pH Bilayers Crosslinking?
PAH 2.0/2.0 9.5 80°C, 1h
PAAm 3.0/3.0 5.5 130°C, 2h, vac
Next Characterization Steps
• Mechanical Force Probe▪ Initial training completed▪ Practice data analyzed
• Stability tests▪ Wear test▪ Antibacterial testing over prolonged time periods ▪ Aqueous environment film durability▪ Shelf life test: Characterize our oldest films
Final Prototype
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Mechanical Wear Test Motivation
• Simulate handling during implantation procedure
• Operating room conditions:▪ Devices handled sterilely▪ Potential handling by surgical
nurse and physician▪ Nitrile glove protected hands
• Risk of coating removal:▪ Loss of antibacterial coating▪ Potential for bacterial infection from:
◦ Skin exposure (wound)◦ Air
Mechanical Wear Test
• Goal: Assess coating delamination risk from handling
• Parameters:▪ Glove probe surface▪ Typical handling load▪ Number of cycles
• Design and build testing apparatus• Standard Test Method
▪ ASTM G99-04▪ “Wear testing with a Pin-on-Disk Apparatus”
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Wear Test Apparatus
• Equipment:▪ Variable speed motor▪ Disk and pin setup▪ Sample stand▪ Gloved probe
• Design under developmentPemPlant Co.
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Wear Test Data Analysis
• Need tool to assess coating wear• Ideal analysis method:
▪ Quantitative ▪ Comparative ▪ Sensitive ▪ Timely
• Current characterization methods:▪ MFP (long T)▪ Methylene blue (less sensitive)
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Gantt Update
• Website: http://web.mit.edu/3.042/team1_07/Website/Website/Contains this and all previous presentations