Antimicrobial Coatings

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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, 3Departmen
t of Materials Science and Engineering,
University of Florida
Center for Particulate Surfactant Systems
(CPaSS) IAB Meeting Columbia University August
20, 2009
2
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

1. http//www.aafa.org/display.cfm?id7sub100cont
   652
2. http//www.nhlbi.nih.gov/resources/docs/07-chtbk.p
   df.
3. http//www.sciencedaily.com/releases/1999/09/99090
   3070829.htm
4. http//alligator.org/articles/2009/01/30/news/loca
   l/090130_avocado.txt

1. Klein, E., et al. (2007) Hospitalizations and
   deaths caused by methicillin-resistant
   Staphylococcus aureus, United States, 19992005.
   Emerging Infectious Diseases
2. http//www.globalhealth.org/news/article/735

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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

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Specific Objective
To develop and test TiO2-PHF or PHF based
coatings for household use, food, agriculture
pharmaceutical industry
2 x faster
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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
PHF
0

• Stability of PHF coating

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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

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Cost Analysis for TiO2-PHF Nanocomposite Coating
TiO2 and PHF costs used in developing economic
estimates
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
Fisher Scientific http//www.radian-group.ru/e
ng/him.html
Comparison between conventional TiO2 and TiO2-PHF
coatings
Dosage Cost (/sqft) Estimated cost reduction
Conventional coating 5 wt TiO2 0.00246
Proposed TiO2-PHF coating 0.1 wt TiO2 0.00185
Proposed TiO2-PHF coating 0.001 wt PHF 0.00185
TiO2-PHF coatings are cost competitive
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Wait a minute!!! PHF by itself is Antifungal
TiO2 PHF is fungistatic
Patent Pending
MIC (ppm) Cost (/Liter)
PHF 0.002 0.0015
Thiabendazole 5 0.0018
Kourai et al., European J Med Chem, 41, 2006
http//www.sciencelab.com/page/S/PVAR/10427/SLT3
937
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Preliminary testing of PHF for Food Agriculture
Applications
After 8 days
After 3 days
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Summary

• TiO2-PHF coatings perform better than
  conventional coatings
• PHF is non-toxic, biocompatible and biodegradable
• Polyhydroxy fullerenes are fungistatic
• Provisional patent filed