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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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Presentation Transcript
introduction
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
approaches
Approaches
  • Biocide Release
    • Silver Ions
    • TiO2
  • Contact Active
    • Hydrophobic Polycations
    • PVP
  • Anti-adhesive
    • Polyethylene Glycol
    • Thermosensitive Polymers
    • Sharklet
biocide release
Biocide Release
  • Release of silver ions
    • Antibacterial properties
  • Titanium Dioxide
    • Reactive oxygen species
  • Simple
  • Convenient
  • Low Cost
silver ions
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
titanium dioxide
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
contact active
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

pvp vinyl n hexylpyridinium
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

pvp vinyl n hexylpyridinium1
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
anti adhesive
Anti-adhesive
  • Modification of surface with synthetic or natural polymer
  • Surfaces that constantly renew themselves by degradation
  • Release of substances that inhibit adherence
peg polyethylene glycol
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

thermosensitive polymers
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
sharklet
Sharklet
  • Surface modification
  • Microtopography
  • Millions of microscopic diamonds that disrupt the ability for bacteria to form biofilms
  • Inhibits growth compared to smooth surface
combination
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
slide15

PEG

PEI + silver ions

hindrances
Hindrances
  • Stability
  • Costly
  • Toxicity
  • Long term effectiveness
  • Limited in vivo research
  • Environmental effects
  • Antibiotic resistance
slide17
Is a completely microorganism free surface really possible?If so and it becomes widely used what will the effects be?
resources
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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