April 5, 2007 Initial Prototype Presentation P E M PemPlant Co. Maricela Delgadillo Kay Furman Yushan Kim

Overview Update ▪Methylene blue staining: more results ▪Contact angle results ▪Mechanical force probe update Initial prototype Future characterization steps

Methylene Blue Staining glass: UV vis. possible Ti: opaque, only qualitative analysis possible.

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),

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) PolycationpHBilayersCrosslinking? PAH2.0/ °C, 1h PAAm3.0/ °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

PemPlant Co. 11 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” PemPlant Co. 12

Wear Test Apparatus Equipment: ▪Variable speed motor ▪Disk and pin setup ▪Sample stand ▪Gloved probe Design under development PemPlant Co. 13

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) PemPlant Co. 14

Gantt Update Website: Contains this and all previous presentations