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Antimicrobial Coatings. Vijay Krishna 1 , Wei Bai 1, 2 , Gayathri Rammohan 1 , Hideya Nakamura 1 , Paul Indeglia 1, 2 , Ben Koopman 1, 2 and Brij Moudgil 1, 3. 1 Particle Engineering Research Center, 2 Department of Environmental Engineering Sciences,
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Antimicrobial Coatings Vijay Krishna1, Wei Bai1, 2, Gayathri Rammohan1, Hideya Nakamura1, Paul Indeglia1, 2, Ben Koopman1, 2 and Brij Moudgil1, 3 1Particle Engineering Research Center, 2Department of Environmental Engineering Sciences, 3Department of Materials Science and Engineering, University of Florida Center for Particulate & Surfactant Systems (CPaSS) IAB Meeting Columbia University August 20, 2009
Background Pharmaceutical Industry • 2 million infections and 90,000 deaths due to disease transmission in hospitals1- fungal infections are the 3rd most common life-threatening systemic infection2 Household Disinfectants • Allergy and respiratory problems account for 25% of emergency room visits in the U.S. annually, and is the #1 chronic cause of school absenteeism3 • $20 billion/yr lost in U.S. due to asthma4 Food and Agriculture Industry • $9 billion/yr lost in U.S. due to fungal diseases in plants5. • A recent threat by laurel wilt fungus, which kills avocado plants, could cost the Florida avocado industry up to $54 million within a year6 • http://www.aafa.org/display.cfm?id=7&sub=100&cont=652 • http://www.nhlbi.nih.gov/resources/docs/07-chtbk.pdf. • http://www.sciencedaily.com/releases/1999/09/990903070829.htm • http://alligator.org/articles/2009/01/30/news/local/090130_avocado.txt • Klein, E., et al. (2007) Hospitalizations and deaths caused by methicillin-resistant Staphylococcus aureus, United States, 1999–2005. Emerging Infectious Diseases • http://www.globalhealth.org/news/article/735
Novel TiO2-PHF nanocomposite for enhanced photocatalysis Advantages of PHF • Photocatalytic nanocomposites synthesized through self-assembly • PHF concentration 10-100 times lower than other enhancers (e.g., metals, dye) • PHF is non-toxic and presently used for therapeutics and cosmetics Approach Conventional Photocatalysis • Sunlight or solar UV (black) lights serve as the excitation source • Eliminates need for chemical disinfectants and their associated toxic byproducts • Microbes are completely mineralized Barrier • Recombination reduces the efficiency of photocatalysis to 10% of theoretical value
Presented at March 2009 CPaSS Meeting (Gainesville, FL) % Dye degradation 5 wt% 0.1 wt% 0.1 wt% TiO2 0 0.001 wt% 0 PHF Enhancement observed with 50 times lower TiO2 conc. Specific Objective To develop and test TiO2-PHF or PHF based coatings for household use, food, agriculture & pharmaceutical industry 2 x faster
Enhancement observed with 50 times lower TiO2 conc. Specific Objective To develop and test TiO2-PHF or PHF based coatings for household use, food, agriculture & pharmaceutical industry Presented at March 2009 CPaSS Meeting (Gainesville, FL) 2 x faster % Dye degradation Questions • Environmental implications of PHF 5 wt% 0.1 wt% 0.1 wt% TiO2 • Economics of PHF usage 0 0.001 wt% 0 PHF • Stability of PHF coating
Water-soluble Biocompatible Biodegradable Polyhydroxy Fullerenes Environmental Implications of PHF Biodegradable • PHF can be degraded by common white-rot fungi, which infects plants. [Schreiner, et al. 2009] Non-toxic at low dosages • PHF dosage for most applications much lower (2 orders of magnitude) than LC50 [Isakovic, et al. 2006, Sayes, et al. 2004, Sayes, et al. 2007, Trajkovic, et al. 2007, Usenko, et al. 2007, Yin, et al. 2009]
25 % Cost Analysis for TiO2-PHF Nanocomposite Coating TiO2 and PHF costs used in developing economic estimates *Fisher Scientific; **http://www.radian-group.ru/eng/him.html Comparison between conventional TiO2 and TiO2-PHF coatings TiO2-PHF coatings are cost competitive
Only Nutrient Nutrient & 0.1 wt% TiO2 Nutrient & 0.1 wt% TiO2 + 0.001 wt% PHF Aspergillus niger growth on a ceramic tile after 3 days in dark and 90% humid environment TiO2 + PHF is fungistatic Comparison with conventional antifungal Wait a minute!!! PHF by itself is Antifungal TiO2 + PHF is fungistatic Patent Pending *Kourai et al., European J Med Chem, 41, 2006; **http://www.sciencelab.com/page/S/PVAR/10427/SLT3937
PHF Control PHF Control PHF: A new class of Fungicide!!! Preliminary testing of PHF for Food & Agriculture Applications After 8 days After 3 days
Next Steps… • Determine mechanism of fungal inhibition pathway for optimizing PHF molecular structure • Optimize PHF coating for stability under different environmental conditions including temperature, humidity, and exposure to water. • Extend PHF application to food and agriculture industry (e.g., food additives & washable coatings on fruits for improving shelf-life) Acknowledgments • State of Florida – CNBS • Industrial partners of PERC Summary • TiO2-PHF coatings perform better than conventional coatings • PHF is non-toxic, biocompatible and biodegradable • Polyhydroxy fullerenes are fungistatic • Provisional patent filed