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Antimicrobial CoatingsAntimicrobial Coatings
Center for Particulate & Surfactant Systems (CPaSS)IAB Meeting
Columbia UniversityAugust 20, 2009
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
BackgrounBackgroundd
2 million infections and 90,000 deaths due to disease transmission in hospitals1 - fungal infections are the 3rd most common life-threatening systemic infection2
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
1. Klein, E., et al. (2007) Hospitalizations and deaths caused by methicillin-resistant Staphylococcus aureus, United States, 1999–2005. Emerging Infectious Diseases
2. http://www.globalhealth.org/news/article/735
3. http://www.aafa.org/display.cfm?id=7&sub=100&cont=652
4. http://www.nhlbi.nih.gov/resources/docs/07-chtbk.pdf.5. http://www.sciencedaily.com/releases/
1999/09/990903070829.htm6. http://alligator.org/articles/2009/01/30/news/local/
090130_avocado.txt
Pharmaceutical Industry
Household Disinfectants
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
ApproachApproachConventional 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
Novel TiO2-PHF nanocomposite for enhanced photocatalysis
Photocatalytic nanocomposites synthesized through self-assembly
PHF concentration 10-100 times lower than other enhancers (e.g., metals, dye)
Advantages of PHF
PHF is non-toxic and presently used for therapeutics and cosmetics
Barrier Recombination reduces the efficiency of photocatalysis to 10% of theoretical value
Specific ObjectiveSpecific Objective
To develop and test TiO2-PHF or PHF based coatings for
household use, food, agriculture & pharmaceutical industry
Presented at March 2009 CPaSS Presented at March 2009 CPaSS MeetingMeeting
(Gainesville, FL)(Gainesville, FL)
5 wt% 0.1 wt% 0.1 wt%TiO2
PHF 0 0 0.001 wt%
% D
ye d
egra
dati
on
2 x faster
Enhancement observed with 50 times lower TiO2 conc.
Specific ObjectiveSpecific Objective
To develop and test TiO2-PHF or PHF based coatings for
household use, food, agriculture & pharmaceutical industry
Presented at March 2009 CPaSS Presented at March 2009 CPaSS MeetingMeeting
(Gainesville, FL)(Gainesville, FL)
5 wt% 0.1 wt% 0.1 wt%TiO2
PHF 0 0 0.001 wt%
% D
ye d
egra
dati
on
2 x faster
Enhancement observed with 50 times lower TiO2 conc.
QuestioQuestions ns Environmental implications of PHF Economics of PHF usage Stability of PHF coating
Environmental Implications of PHFEnvironmental Implications of PHF
BiodegradablePHF can be degraded by common white-rot fungi, which
infects plants. [Schreiner, et al. 2009]
Polyhydroxy Fullerenes
Water-solubleBiocompatibleBiodegradable
Non-toxic at low dosagesPHF 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]
Cost Analysis for TiOCost Analysis for TiO22-PHF Nanocomposite -PHF Nanocomposite CoatingCoating
Dosage Cost ($/sqft)*
Estimated cost
reduction
Conventional coating
5 wt% TiO2 $0.00246 —
Proposed TiO2-PHF coating
0.1 wt% TiO2$0.00185
0.001 wt% PHF
Comparison between conventional TiO2 and TiO2-PHF coatings
Small-scale price($/gram)
Scale-up cost reduction factor
Bulk Price($/gram)
TiO2 $0.16* 61.5 (calculated) $0.0026**
PHF $750 60 (assumed) $12.50
TiO2 and PHF costs used in developing economic estimates
25 %
*Fisher Scientific; **http://www.radian-group.ru/eng/him.html
TiO2-PHF coatings are cost competitive
Only Nutrient
Aspergillus niger growth on a ceramic tile after 3 days in dark and 90% humid environment
Wait a minute!!! PHF by itself is AntifungalWait a minute!!! PHF by itself is AntifungalNutrient &
0.1 wt% TiO2
Nutrient & 0.1 wt% TiO2 + 0.001 wt% PHF
TiO2 + PHF is fungistaticTiO2 + PHF is fungistaticPatent Pending
Comparison with conventional antifungal
MIC (ppm) Cost ($/Liter)
PHF 0.002 $0.0015
Thiabendazole
5* $0.0018****http://www.sciencelab.com/page/S/PVAR/10427/SLT3937
*Kourai et al., European J Med Chem, 41, 2006;
Preliminary testing of PHF for Food & Preliminary testing of PHF for Food & Agriculture ApplicationsAgriculture Applications
Control PHF
Control PHF
After 3 days
After 8 days
PHF: A new class of Fungicide!!!
SummarySummary TiO2-PHF coatings perform better than conventional coatings
PHF is non-toxic, biocompatible and biodegradable
Polyhydroxy fullerenes are fungistatic
Provisional patent filed
Next Steps…Next Steps…
Extend PHF application to food and agriculture industry (e.g., food additives & washable coatings on fruits for improving shelf-life)
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.
AcknowledgmeAcknowledgmentsnts Industrial partners of PERC State of Florida – CNBS