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