Deborah Ohiani-Jegede
Partners: Nkele Davis and Nick Xydis


Group 24 , Client :Brad Clay, bio Merieux

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 noncompliance

Contact lens contamination can lead to microbial keratitis,
conjunctivitis, staphylococci which may require surgery

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




Effectiveness




Cost: < $200 (prescribed by
doctor)
Power Draw: < .25kWhr per
application
95% biofilm destruction
biofilm growth prevention
No damage to lens case and lens
Durability

meets all other specification
requirements after 5 years
Choose Disinfection Technology Disinfection Technologies




Construct Final Product Design


Hydrogen Peroxide Solutions
Heat Treatment
Pulsed Electric Field
Ultraviolet Radiation
Sonication
Atmospheric Pressure RoomTemperature Plasmas



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



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



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


Tested UV radiation, UV + Sonication, Cold Plasmas
Staph epidermidis - test bacteria
o
o
o

Common microbe on contact lens and contact lens cases
Biofilm forming strain chosen
Diluted bacteria to 1McFarland (3e8 bacteria/mL)
Testing on polystyrene coverslips
o
Common plastic in contact lens manufacturing




UV-C radiation at 254nm
produced using MaxLamp FIlter
Three five-minute treatments
biofilm on coverslip
Streaked samples on agar
plates in between trials
Plates grown overnight in
incubator at 36°C


Extremely effective in destroying biofilms
Solution added to coverslip to prevent drying/warping





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





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
Weight
Ultraviolet Radiation
Ultraviolet Radiation +
Sonication
Cold Plasma
Efficacy
5
5
3
3
Safety
4
4
4
3
Durability
4
4
3
3
Cost
3
3
2
4
Speed of Use
2
5
4
3
76
57
57
TOTAL
UV+Sonication
Plasma
Motor engine to
sonicate









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

Nkele
o
o

Deborah
o
o

Sonication and Mechanical Turbulence Expert
Lead Ergonomics Designer
UV Treatment and Biofilm Growth Expert
Lead Mechanical Designer
Nick
o
o
Plasma and Electric-Field Treatment Expert
Lead Electrical Designer

November
o
o
o
o
o
o
o
o
o
o
o
o
o
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
o
o
o
2nd - Final Presentation
4th - Final Report Due
5th - Celebratory Retreat
Questions?