Antibacterial surfaces
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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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Antibacterial Surfaces

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Antibacterial surfaces

Antibacterial Surfaces

Vanessa Lipp


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


Antibacterial surfaces

PEG

PEI + silver ions


Hindrances

Hindrances

  • Stability

  • Costly

  • Toxicity

  • Long term effectiveness

  • Limited in vivo research

  • Environmental effects

  • Antibiotic resistance


Antibacterial surfaces

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


Questions or comments

QuestionsorComments?


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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