1 / 19

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

gates
Télécharger la présentation

Antibacterial Surfaces

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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.

More Related