PAYLOAD DESIGN TO EVALUATE BIOFILM RESISTANT COATINGS FOR SPACECRAFT WATER SYSTEMS Taylor Booker, Abraham Brown, Sam Kreslins, Devan Naes, Gabriel Nelson, Melissa Phung, Lindsey Stachofsky Sponsor: Dr. Matthew Bernards, NASA EPSCoR Instructor: Dr. Russell Qualls
EXPERIMENTAL BUILD
DATA ANALYSIS Image Analysis • Auto-analysis program that isolated biofilm growth on tested surfaces
BACKGROUND • Bacteria strains Ralstonia picketti and Burkholderia cepacia identified at concerning levels on the ISS water system
• Calculated total area of biofilm as a percentage
• Designed an experimental apparatus to be sent to ISS
Contact Angle
• Testing the effectiveness of bacterial resistant polymer coatings on stainless steel for inhibition of bacterial attachment
• Measured contact angle of polymers to quantify wettability
REQUIREMENTS
Fig 3: Isolating Biofilm Growth
• Combined with biofilm area data to show relationship between hydrophobic character and bacteria resistance
• Maximum dimensions: 3.75” x 3.5” x 12” • Experimental apparatus cannot exceed 3.8 kg • Start operation on powerup without user interface • Three chambers: R. picketti, B. cepacia, Co-culture
• Biosafety Level 2 requires three levels of containment • Double redundancy in bacteria release system
POLYMER COATINGS
Test Chambers
Assembly
• “Nesting Doll” design allows for triple containment • Two linear actuators dispense bacteria into chambers • Media mixed by caged stir bar • DC motor with attached magnets induces stirring • Electronics controlled by Arduino Teensy 4.1
BACTERIA TESTING
Cleaned Stainless Steel Substrate
Fig 4: Contact angle of polymers compared to biofilm growth
TEAM
• Optimal growth medium determined to be Luria Broth
Acknowledgements
• Temperature and pH increased during growth phase
• Zane Holliday, mentor
• Confirmed no off-gassing or pressure buildup in chambers
• Charles Cornwall, machinist
• Adrienne Shea, mentor
• Sharjeel Jokhio, mentor
Funding Grant # 80NSSC22M0120
• Substrate surface initiated using methacryloxypropyltrichlorosilane
• Coatings synthesized with TMA and CAA monomers • Studied effect of cross linkers and film thickness on biofilm adhesion • Random copolymerization occurs due to natural charges of the monomer units and the zwitterionic crosslinker
Fig 1: Microscopic Image of Burkholderia cepacia
Fig 2: Experimental apparatus to test biofilm growth conditions and polymer validation
2023 Capstone Project