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Antibacterial Surfaces

Antibacterial Surfaces. Vanessa Lipp. Introduction. Greater need for antibacterial surfaces Microbial resistance – MRSA has caused more deaths in the USA than HIV Medical implants – 40% of nosocomial infections caused by urinary tract infections Biofilms can also cause economic problems

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Antibacterial Surfaces

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  1. Antibacterial Surfaces Vanessa Lipp

  2. Introduction • Greater need for antibacterial surfaces • Microbial resistance – MRSA has caused more deaths in the USA than HIV • Medical implants – 40% of nosocomial infections caused by urinary tract infections • Biofilms can also cause economic problems • Protective EPS matrix protects biofilms once they form • Antibacterial properties must target their formation

  3. Approaches • Biocide Release • Silver Ions • TiO2 • Contact Active • Hydrophobic Polycations • PVP • Anti-adhesive • Polyethylene Glycol • Thermosensitive Polymers • Sharklet

  4. Biocide Release • Release of silver ions • Antibacterial properties • Titanium Dioxide • Reactive oxygen species • Simple • Convenient • Low Cost

  5. Silver Ions • Binding to DNA • Prevents mitosis in prokaryotes • Form strong molecular bonds with S, N, and O • Unusable by bacteria • Oxidation of other substrates used by bacteria • Degradable matrix – must be reloaded • More testing still to be done on kinetics, cytotoxicity and efficiency

  6. Titanium Dioxide • Photocatalyst with strong oxidizing power • Irradiated by UV rays • Formation of hydroxyl radicals, superoxide radical anions, H2O2, and other ROS • Continuous release • Requires water, UV light and oxygen • Loaded with silver ions

  7. Contact-Active • Killing of microbes upon contact • Hydrophobic polycations are capable of disrupting the cell membrane of bacteria • Positive charge and hydrophobic properties attract bacteria

  8. PVP (vinyl-N-hexylpyridinium) • Coating capable of killing Gram- and Gram+ bacteria • N-alkyl chains must be between three and eight units to be bactericidal • Repel each other in order to maintain flexibility and hydrophobicity

  9. PVP (vinyl-N-hexylpyridinium) • Dry PVP coated surfaces were able to kill 94-99% of bacteria • Effective in killing MRSA by attacking cell wall • Bacteria unlikely to develop resistance • Immobilization, flexibility, and spacing questions

  10. Anti-adhesive • Modification of surface with synthetic or natural polymer • Surfaces that constantly renew themselves by degradation • Release of substances that inhibit adherence

  11. PEG (Polyethylene Glycol) • Hydrogel • Extremely hydrophilic • Used in conjunction with a negatively charged surface • Anti-adhesive effect of over 99% against three common types of bacteria

  12. Thermosensitive Polymers • Change in hydration state gives the ability to switch between adhesive and repelling state • Wettability of Poly(N-isopropylacrylamide) (PNIPAAM) changed from favorable to unfavorable for marine microbes • Over 90% of the microorganisms were removed • Other “smart” polymers being tested that respond to environmental stimuli such as temperature, pH, electrical potential, or light

  13. Sharklet • Surface modification • Microtopography • Millions of microscopic diamonds that disrupt the ability for bacteria to form biofilms • Inhibits growth compared to smooth surface

  14. Combination • Silver ions function as biocide release system and contact-active • PEG acts as microbe-repelling modification • PEI (poly ethylene imine) derivative takes up silver ions • PEG grafted to surface • Silver ions exhausted –> microbes repelled by PEG

  15. PEG PEI + silver ions

  16. Hindrances • Stability • Costly • Toxicity • Long term effectiveness • Limited in vivo research • Environmental effects • Antibiotic resistance

  17. Is a completely microorganism free surface really possible?If so and it becomes widely used what will the effects be?

  18. QuestionsorComments?

  19. Resources • Berman E. Toxic metals and their analysis. London: Heyden; 1980. P. 121-145. • Borman, S. (2001, May 28). Designed surface kills bacteria. Chemical & Engineering News, 79(22), 13. • Hanes, J.L., Mansour, D. (1989). U.S. Patent No. 4,886,505. Washington DC: U.S. Patent and Trademark • Ho, C., Tobis, J., Sprich, C., Thomann, R. and Tiller, J. (2004), Nanoseparated Polymeric Networks with Multiple Antimicrobial Properties. Advanced Materials, 16: 957–961. • Humphries M, Nemcek J, Cantwell JB et al. (1987). The use of graft-copolymers to inhibit the adhesion of bacteria to solid-surfaces. FEMS Microbiol Ecol 45:297-304. • Ista LK, Perex-Luna VH, Lopez GP, (1999) Surface-grafted, environmentally sensitive polymers for biofilm release. Appl Environ Microbiol 65:1603-1609. • Klevens RM, Morrison MA, Nadle J et al. (2007) Invasive methicillin-resistant Staphylococcus aureusinfections in the United States. JAMA 298: 1763-1771. • Secinti, KD. (2011). Nanoparticle silver ion coatings inhibit biofilm formation on titanium implants. Journal of Clinical Neuroscience, 18(3), 391-95. • Slawson RM, Van Dyke MI, Lee H, Trevors JT (1992). "Germanium and silver resistance, accumulation, and toxicity in microorganisms". Plasmid27 (1): 72–9. • Tiller, J.C. (2011). Antimicrobial surfaces. Advances in polymer science (pp. 1-25). Springer Berlin/Heidelberg. • Wei-Guo, X, An-Min, C, & Qiang, Z. (2010). Preparation of TiO2 thin film and its antibacterial activity. Journal of Wuhan University of Technology--Materials Science Edition, 19(1), 16-18. • Yang, H, & Weiyuan, JK. (2006). Thermoresponsive gelatin/monomethoxy poly(ethylene-glycol)-poly(d,l-lactide) hydrogels: formulation, characterization, and antibacterial drug delivery. Pharmaceutical Research, 23(1), 205-209. • Yu, BY, Leung, KM, Guo, QQ, Lau, WM, & Yang, J. (2011). Synthesis of ag-tio2 composite nano thin film for antimicrobial application. Nanotechnology, 22(11), 11560.

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