Willkommen
Welcome
Bienvenue
Projektvorschlag
"non-leaching antimicrobials"
Nano Initiative des Bundesministeriums für Verkehr, Innovation und Technologie
Workshop "Potenziale der Nanotechnologie für Unternehmen"
Dr. Dirk Hegemann (Empa)/ Dr. Gaffar Hossain (V-trion)
Non-leaching antimicrobials
Goal: To produce non-leaching antimicrobial material through
plasma (assisted) nanocoating of antimicrobial substances or
catalytically active surfaces
www.empa.ch/advancedfibers
Non-leaching antimicrobials
Approaches
1)
Antimicrobial substances (e.g, quaternary ammonium salts or others) will be
linked covalently to the plasma nanocoated surface.
2)
Generation of metal (oxides) island (with dissimilar metals) over the
catalytically active surfaces
QAC or other compounds
Substrate
Plasma
nanocoating
Metal (Oxides)
deposition
Non-leaching
antimicrobial material
18.12.2014
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3
Non-leaching antimicrobials
Mode of antimicrobial action
Non-leaching antimicrobial
repulsion
killing
2
Exclusion
steric repulsion
Electrostatic
repulsion
Low surface
energy
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Biocide
releasing
1
Contact-active biocidal
Immobilization of antibacterial compounds
Grafting onto functionalized surfaces
Substrate
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5
Immobilization of antibacterial compounds
Grafting onto functionalized surfaces
O
Antimicrobial compounds
HO
O
CH3
HO
OH
Lauryl Gallate (LG)
Multifunctional (antimicrobial/
antioxidant/ hydrophobe) Gallate
compounds
Biocidal polymers with quarternary ammonium
groups
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Hematoporphyrin
(Photoinduced antimicrobial)
 Aminolevulinic acid
 Photofrin
 Enzyme etc
Immobilization of antibacterial compounds
Grafting onto functionalized surfaces
Substrate
e.g. grafting of quaternary ammonium compounds (Qac) onto functionalized surfaces
Cell membrane
Qac, for example: 3-(trihydroxysilyl) propyldimethyloctadecyl
ammonium chloride
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Biocidal action to destry the cell wall
7
Catalytically active surfaces
Deposition of dissimilar metals (metal oxides)
Generation of reactive oxygen species (ROS)
O2• –
TiO2
Ag, Au, Pt, Pd,
Cu, Fe, Zn…
OH• + H+
2 H + O2
TiOx
H 2 O2
4 H•
Au islands
PET filament
O2
Ag
H2O
→ formation of ROS
(O2–, OH•, HO2, H2O2 etc.)
→ antibacterial effect on respiratory
system of bacteria
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8
Catalytically active self-cleaning and
antimicrobial surfaces
S. Aureus/ P.aeruginosa/ E.Coli
Antimicrobial
% Viability
ROS formation at hv > 290 nm
Concentration of nanoparticles (mg/ mL)
Self-cleaning
18.12.2014
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Coffee / Wine
Coated CO Untreated
Stain decomposition mechanism at hv> 440
0h
8h
24 h
9
Catalytically active self-cleaning and
antimicrobial surfaces
Antenna effect
A
_.
A
h
D
v
D
+.
Chlorophyll
molecules Reaction
center (RC)
Photosynthesis
process
Photocatalytic antimicrobial compounds
(Hematoporphyrin and photofrin)
Photosensitizer (PS)
Photocatalytic
action
PS-Excited state
Photo-oxidation 1
Biomimetic
process
Molecular oxygen
Photo-oxidation 2
Molecular oxygen
O2
1O
2
H2O2
Hydrophobic
pocket
Free Oxygen radicals
Hosting capacity and
Solubilisation of organic dirt
Biomolecular oxidation
and cellular damage
www.empa.ch/advancedfibers

Management of infec]ous diseases in a high volume se@ng