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Biofilm Destructive System

Biofilm Destructive System. Deborah Ohiani-Jegede Partners: Nkele Davis and Nick Xydis. Group 24 , Client :Brad Clay, bio Merieux. Demonstration of Need. B iofilms are an aggregate of microorganism where cells are stuck to each other and/or a surface

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Biofilm Destructive System

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  1. Biofilm Destructive System Deborah Ohiani-Jegede Partners: Nkele Davis and Nick Xydis Group 24 , Client :Brad Clay, bio Merieux

  2. Demonstration of Need • Biofilms are an aggregate of microorganism where cells are stuck to each other and/or a surface • Can form contact lens cases due to improper cleaning/user non-compliance • Contact lens contamination can lead to microbial keratitis, conjunctivitis, staphylococci which may require surgery

  3. Design Requirements • Usability • Within 3” x 5” • Weight: < 5 lb • Operating time: < 1 hours • Visual timer display • Set up Time: < 30 seconds • Sound during application: < 40 dB • Autonomous system, turns on and off automatically • Waterproof • Economics • Cost: < $200 (prescribed by doctor) • Power Draw: < .25kWhr per application • Effectiveness • 95% biofilm destruction • biofilm growth prevention • No damage to lens case and lens • Durability • meets all other specification requirements after 5 years

  4. Overview of Design Alternatives Choose Disinfection Technology Disinfection Technologies • Hydrogen Peroxide Solutions • Heat Treatment • Pulsed Electric Field • Ultraviolet Radiation • Sonication • Atmospheric Pressure Room-Temperature Plasmas Construct Final Product Design

  5. Ultraviolet Radiation • UV-C radiation (100-280nm) effectively stunts biofilm growth • Penetrates bacteria to nucleus to irreversibly damage the DNA • 254nm breaks molecular bonds of microsomal DNA

  6. UV Radiation + Sonication High frequency shaking (sonication) can disrupt biofilm by breaking up extracellular matrix and dislodging from surface Coupled with another method, could potentially make disinfecting more effective Sonication at 40kHz for 5minutes had success in previous literature

  7. Cold Plasmas Apply high voltage between dielectric electrodes to ionize surrounding air Reactive oxygen species (O3, H202, O2, OH-) destroys biofilms via oxidation “Plasma needle” – high voltage to metal wire to ionize surrounding air

  8. Analysis Performed to Choose Design • Tested UV radiation, UV + Sonication, Cold Plasmas • Staph epidermidis - test bacteria • Common microbe on contact lens and contact lens cases • Biofilm forming strain chosen • Diluted bacteria to 1McFarland (3e8 bacteria/mL) • Testing on polystyrene coverslips • Common plastic in contact lens manufacturing

  9. UV Treatment UV-C radiation at 254nm produced using MaxLampFIlter Three five-minute treatments biofilm on coverslip Streaked samples on agar plates in between trials Plates grown overnight in incubator at 36°C

  10. Results from UV Testing • Extremely effective in destroying biofilms • Solution added to coverslip to prevent drying/warping

  11. UV+Sonication Treatment • Prepared coverslip, placed in ultrasonic cleaner, and weighted down with bottle • Treated for 5 minutes at 40kHz, then with 5 min UV • Cycle repeated 3 times total • Swab and plate samples after each treatment • Plates grown overnight in incubator at 36°C

  12. UV+Sonication Results

  13. Cold Plasma Treatment • Small hole bored into petri dish cover contain plasma • Generator at 30kV • Three five-minute treatments of plasma • Swab and plate samples after each treatment • Plates grown overnight in incubator at 36°C

  14. Cold Plasma Results

  15. UV vs. Plasma Comparison

  16. Pugh Chart

  17. Choosing a Final Design UV+Sonication Plasma Motor engine to sonicate

  18. Chosen Design • Deep UV light • Single Button • Timer Display • Safety Interlock • Door sensors • LED Light • Minimal light intensity of 30 microWatts/cm2 • 30-minute application • Side Panel Access Door

  19. Group Responsibilities • Nkele • Sonication and Mechanical Turbulence Expert • Lead Ergonomics Designer • Deborah • UV Treatment and Biofilm Growth Expert • Lead Mechanical Designer • Nick • Plasma and Electric-Field Treatment Expert • Lead Electrical Designer

  20. Design Schedule • November • 2nd - Optimizing Physical Design • 4th - Performing UV Wavelength Testing • 5th - Continued Wavelength Testing • 6th - Ensuring Optimal UV Application Technique • 7th - Evaluation of Experimental Results • 8th - Meet with Manufacturing • 10th - Computer Model of Design • 13th - Brainstorming compatible materials • 15th - Creating official List of Materials • 16th - Design Verification • 22nd - Final Paper Draft • 28th - Thanksgiving • 29th - Final Paper Revision • December • 2nd - Final Presentation • 4th - Final Report Due • 5th - Celebratory Retreat

  21. Questions?

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