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PemPlant Co.

E. P. M. PemPlant Co. March 8, 2007 Design Review. Maricela Delgadillo Kay Furman Yushan Kim. Project Overview. Exploring use of Antibacterial Polyelectrolyte Multilayers (PEMs) on implantible medical devices such as pace makers

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PemPlant Co.

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  1. E P M PemPlant Co. March 8, 2007 Design Review Maricela Delgadillo Kay Furman Yushan Kim PemPlant Co.

  2. Project Overview • Exploring use of Antibacterial Polyelectrolyte Multilayers (PEMs) on implantible medical devices such as pace makers • 6% of all vascular surgeries result in surgery site infection (Health Protection Agency) • Packaged and handled sterilely • 1-2 hr surgical procedure • Explore the stability of antibacterial properties of PEMs on glass. • Develop the glass system on medical grade Ti PemPlant Co.

  3. Experimental Objectives • Analyze glass PEM antibacterial properties • Currently only experiments across 2 hour time points have been performed • Test the stability of antibacterial PEMs at 4 and 8 hour time points • Develop and characterize the glass/PEM system on Ti: • Stability Testing • In air • In buffer • Mechanical testing • Nanoindentation, MFP • Bactericidal testing PemPlant Co.

  4. Key Project Accomplishments • Administrative Accomplishments • All Training Completed • Website Completed • Link to:http://web.mit.edu/3.042/team1_07/Website/Website/ • Experimental Accomplishments • Ti substrates • Purchased and cut (Yin-Lin) • Cleaning method developed • Coated with PAA/PAAm system • Completed PEM Formulations: • PAA/PAAm on silane-glass slides • PAA/PAH on silane-glass slides • Bacteria inoculation performed • Cytophillic biological agent selected (RGD) PemPlant Co.

  5. Further exploring glass PEM Antibacterial Properties • Will PEMs continue to display antibacterial properties at across longer time points? • Staph. Epidermidis • 4 h, and 8 h incubations • Microscopy PAAm=Polyacrylamide PemPlant Co.

  6. Developing PEMs on Ti • Test duration 2 wks-1 mo • Ti PEM stability/mechanical properties unknown • Visual observation • methylene blue binds to carboxyl groups to give visual quantification of the polymer on the sample PemPlant Co.

  7. Film construction Layer-By-Layer dipping technique • PAA/PAH 2.0/2.0 • 9.5 Bilayers (PAA first and last layer) • 15 min dip in polymer PAA (anion) and PAH (cation) • 2,1, and 1 min dip in DI water • Crosslink at 80°C for 1 h • PAAm/PAA • 5.5 Bilayers (PAA first and last layer) • 15 min dip in PAAm (cation) and PAA (anion) • 2,1, and 1 min dip in DI water at pH 3 • Crosslink at 130°C for 2 hours under vacuum PemPlant Co.

  8. Film Properties • PAAm/PAA (pH=3) • Prevent Hydrogen bonds from hydrolyzing at a neutral pH • Must use low pH to prevent film break up • Not stable in water until crosslinked PemPlant Co.

  9. Preparing and Cleaning Ti surface • Simple cleaning method acquired from several literature sources • Remove organic contaminants • Clean surface with acetone • Rub with kimwipe • Sonicate in 100% ethanol for 5 minutes • XPS and Contact angle test will be used to ensure oxide layer remains on Ti after it is cleaned PemPlant Co.

  10. Anticipated PEM Mechanical Properties • Mechanical Data Reference Points: Thompson, Van Vliet, et al. (2005) PAA-terminal PAH-terminal PemPlant Co.

  11. Anticipated Bacterial Response • Cell response possibly affected by • Mechanical properties • fibroblasts prefer stiffer substrates, on the order of 10^8 Pa • Surface chemical characteristic • cells have a positive surface charge, they stick better to the negative surface charged PAA-topped films (Carboxylates) • Data refers to fibroblast, however, unpublished data shows similar trends for bacteria. PemPlant Co.

  12. Previous Phase-Level Gantt Chart • Glass PEM, Titanium PEM, Mechanical, Bacterial, Cytophillic PEM, Fibroblast Seeding PemPlant Co.

  13. Design Review Evaluation • Considerations Prompting Re-evaluation: • Ambitious team goals • Initial scheduling of Gantt • Implemented Realistic Timeframes with Achievable Goals • SMART= specific, measurable, achievable, realistic, time-based • Utilized Consultations: • Prof. Chiang • Todd • Mike PemPlant Co.

  14. Design Review Evaluation • Revised Phase-Level Gantt Chart: • Removed cytophillic experiments • Stream-lined several experiments • More realistic, achievable time frames PemPlant Co.

  15. Design Review: Team Goals • Antibacterial PEM Coatings on Glass • Low risk, higher benefit • Novel longevity experiments • Measurable outcome: 4 h, 8 h antibacterial character • Transfer PEM System to Titanium • Higher risk, large potential benefit • Novel substrate for MIT • Provide knowledge-base for Industry • Measurable outcome: PEMs on Ti, mechanical characterization PemPlant Co.

  16. Next Steps • Upcoming weekend: • Inoculate bacteria (prepare for testing) • Expose glass PEMs (PAA/PAH and PAAm) to bacteria • Take images of 2 h, 4 h exposure • Before next presentation: • Analyze bacteria experiment results • Assess presence of PEMs on titanium PemPlant Co.

  17. E P M Questions? • PemPlant, Co. Homepage: • http://web.mit.edu/3.042/team1_07/Website/Website/ PemPlant Co.

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