Alternative approaches in the
treatment of biodeterioration
of cultural materials, using the
free-radical nitric oxide (NO)
Caroline Kyi
PhD candidate Centre for Cultural Materials Conservation
and ARC Centre of Excellence for Free Radical Chemistry
and Biotechnology, University of Melbourne
Centre for Cultural
Materials Conservation
Micro Organisms
Macro Organisms
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Centre for Cultural
Materials Conservation
ECOLOGICAL
FACTORS
Primary colonisers
Pioneer stage
Mature stage
Bacteria
Fungi
Bryophytes
Lichens
Higher plants
Increased biodiversity
time
Micro-degradation
Symbiotic relationships
Increase in biomass and
metabolic activity
Biodeterioration
Macro-degradation
3: Altered material: degradation
SUBSTRATE
BIORECEPTIVITY
2: Added material: intervention, atmosphere
1: Original material: organic/inorganic
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Centre for Cultural
Materials Conservation
General approaches in the treatment of biodeterioration
Preventative: Influenced by the material being treated
and its environment.
• Reducing biodeteriorgens
• Climate control
Direct methods: Requires development of specific
intervention criteria
• Physical
• Chemical
• Bioremediation
Biocide being brushed onto the
back of a canvas (top) and
sprayed onto a stone monument
(bottom)
Caneva, et al, (eds) PLANT BIOLOGY FOR CULTURAL HERITAGE: BIODETERIORATION, 2008 The J. Paul Getty Trust, Los Angeles.
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Centre for Cultural
Materials Conservation
An alternative treatment approach utilizing nitric oxide (NO)
Background
• Free radical molecule of research interest
• Produced by natural and anthropogenic activities
• Therapeutic agent
• Atmospheric pollutant (NOx)
Lewis structure of nitric oxide
molecule showing paired (-)
and unpaired () electrons
• Possesses antimicrobial properties
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Materials Conservation
Nitric oxide has previously been shown to induce biofilm dispersal
Inhibition of the successful establishment of
communities of micro-organisms by disrupting
biofilm formation
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Centre for Cultural
Materials Conservation
Introduced
bacteria
Endogenous source
(bacterial origins)
Autocthonus
bacteria
Sources of nitric
oxide
Exogenous Source
(nitric oxide donor)
DETA/NO
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Centre for Cultural
Materials Conservation
Establishment of cultural materials broth (CMO)
Nitrate (NO3-)
Retrieval of a representative community
Nitrate reductase
Bacteria only and
higher organisms
Nutrient dependant
Slow growers
Polymicrobial cultures/biofilms
Nitrite (NO2-)
Nitrite reductase
Bacteria
Nitrate reducers?
Nitric oxide (NO)
Released to
atmosphere
Reduced further
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Centre for Cultural
Materials Conservation
Imaging of nitric oxide in
association with bacterial
cells
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Centre for Cultural
Materials Conservation
Introduced nitric oxide: Selection of a nitric oxide donor
Diazeniumdiolate DETA-NO
Half life 24 hours at 22-25°C
Minimal cytotoxic effects of by-products
Adverse effects of compound on materials?
1-[N(2-Aminoethyl)-N-(2ammoniethyl)amino]dizen-1ium-1,2-diolate
(DETA/NO)
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Centre for Cultural
Materials Conservation
Introduced nitric oxide: Preliminary results
Evidence of inhibition of growth and poor formation of biofilms
Synergistic relationship with antibiotics and biocides
Considerations
Compare effect of introduced and bioremedial forms of NO
Examine donor effect using probe
Effect on materials
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Centre for Cultural
Materials Conservation
2012 onwards
Experimental
• Further and comparative testing of DETA/NO
• Improved and increased application of probe
• Investigations involving cultural materials
• Determination of composition cultural material organisms stock broth
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