Post on 26-Dec-2015
Toxicity of Naturally-Occurring and Man-made
NanoparticlesPresented by: Tina Suen, Nisha Kailai, Denise Lieu, and Ikran Aden
BIOL 475 February 29th, 2012
Agenda
• Background information
• Naturally-occurring toxic nanoparticles
• Incidental man-made particles
• Engineered man-made particles
• Contemporary cases and Issues
Definition
• Nanoparticle: particles that range in size from 1 to 100 nm
• Nanometer: = 10-9 m
• Nanotechnology:deals with dimensions less than 100 nm (especially the manipulation of individual atoms and molecules)
Fun Facts• Nanotechnology is being used everywhere
today – even in some surprising products! • iPhone app: findNano
Regulations
• Canadian government preventing detrimental effects of nanoparticles to human health and the environment
• Nanoparticle use regulated by:- Health Canada- PMRA- CFIA
Why should we care?• Nanoparticles can be found everywhere
• Can be ingested, inhaled, or absorbed
• If incorporated into other organisms, may enter our food chain and indirectly affect us
• Regulations have not yet been established for labelling all nanoparticles
• Health concerns: accumulate in tissues
Viruses• Definition: small infectious particles that can only replicate
intracellularly
• Size: vary from 20nm to 300nm
• Toxicity: depends on virus– Toxic to all forms of life (ie. bacteriophage)
• Mode of Transmission: inhaled, ingested, or contact
• Health Risk: HIV, influenza, hepatitis, ebola, HPV, smallpox, etc.
Spores• Definition: Structure made by some organisms to survive for a long
time in harsh conditions
• Size: ~7nm – >100nm
• Source: Found in many bacteria, plants, and fungi
• Toxicity: varies; mold spores are toxic to humans
• Mode of Transmission: inhalation or ingestion
• Health Risks: Food poisoning (Clostridium botulinum) respiratory tract infections (Bacillus anthracis)
Endotoxins
• Definition: toxins released from the death of bacteria, often containing lipopolysaccharides or lipoproteins
• Size: ~10kDa
• Source: outer membranes of Gram-negative bacteria
• Toxicity: varies
• Mode of Transmission: ingestion or aerosolized
• Health Risks: fever, inflammation and endotoxic shock
Bioaerosols• Definition: Air-borne particles that contain living organisms or particles
that are released from living organisms with biological action indicated by its viability, infectivity, and allergencity.
• Size: 20 nm to > 100 micrometer
• Primary biological aerosol: virus, bacteria, fungal spores, plants pollen particles. Size range from 10 nm to 100 micrometers
• Source:- Processing of wastewater and solid wastes- aerial application of liquid manures for agriculture- meat/poultry/fish processing plants and biological laboratory procedures; vacuuming, etc.
BioaerosolsToxicity:
- For bioaerosols to be infectious or pathogenic, it must be viable. - viability changes with season, weather and geographic location.
Modes of transmission to human:- skin, eyes and respiratory system. The most sensitive route is inhalation.
Health risk: - allergies, eye irritant- airway constriction
CDNPsSources:
– Stationary industrial sources (coal/oil/gas boilers, incinerators, metal smelting and refining)
– Vehicle emissions
Factors of toxicity:- Particle size, solubility and chemical composition
Health Risks:– Lungs (inflammation)– Irregular heart rate
- Brain (accumulation of Manganese)- Genes (damage to DNA
Fly Ash
Electron microscope (SEM): Fly ash particles at 2,000x magnification
•Definition: Particulate Matter from mineral and metal contaminants of organic fuels
•Residue behind combustion of coal
•Generally spherical in shape
•Size: ranges from 0.5 µm to 100 µm.
•Two groups: Residual Oil Fly Ash- ROFA ( from liquid fuel) and solid fuel
Fly Ash• Residual oil fly ash (ROFA) contains sulfate and heavy metals.
• Solid fuel fly ash from burning of coal.
• Toxic trace heavy metal elements in fly ash (eg Arsenic, cadmium, uranium, mercury)
• Mode of entry: Inhalation
• Environmental Problem:– Ground water, soil and river contamination (leaching)– Health Risks
Fly Ash• Effects on soil:
– Fly ash is highly soluble in water and can be easily penetrated into soil – It changes the soil's chemical equilibrium such as increase in pH,
salinity and level of toxic elements
• Health Risk:– Lung Damage: Toxic (Coal) particles damage epithelial cells.
• Uses: – Increase viscosity of liquid phase (aggregate suspended cement grains)– Improve resistance
Polytetrafluoroethylene (PTFE)
SEM image of PTFEs on Carbon Nanofibers (CNFs)
•Fluoro-polymer
•Thermal stability
•Electrical resistance
•Average sizes:~ 90nm for Carbon Nanofibers (CNFs)~ 130nm for PVP~ 150 nm for alumina ~ 200 nm for silica
Polytetrafluoroethylene (PTFE)Source: Fumes in indoor
- PTFE can be generated at a temperature >425oC; 18nm diameterMode of Transmission to human: Inhalation
- Absorption of reactive gases and the radicalsEnvironmental problem:
- Air pollution, Health RiskHealth risk:
- Lung inflammation, oxidative injury, and accumulation of fluid in lungs- Death in rats when they are exposed at the rate of ~0.05mg m -3 for 15 min- Case study: A worker had died due to the release of PTFE product in the workplace. Hence it has been proved that even very low concentration is toxic and lethal to human beings.
Engineered NanoparticlesMetal-based:• TiO2 in sunblock• Silver for antimicrobial
surfaces (clothes, furniture, cooking ware)
• Quantum dots (imaging)• Electronics• Medicine – joint
replacements
Carbon-based:• Food packaging• Paints• Electronics• Medicine – drug delivery (in
development)• Oil spill remediation• Diamond films• Lubricants• Special rubber additives
Other sources: manufacture, wear and tear, waste
The issues
• Discrepancies in jargon, classification• Experimental design• Lack of supporting literature
The issues• Discrepancies in jargon, classification
– Metal vs organic• Experimental design
– Excessive dosing– Dying is boring
• Lack of supporting literature
• No regulations for labeling, disposal, handling of commercial products eg clothing, sunblock
Factors of nanoparticle toxicity
• Size vs surface area• Coatings• Agglomeration • Production contaminants• Surface charge & chemistry• Crystal structure• Biopersistence (largely unknown)
Size:
- Effect is proportional to surface area - Translocation to 2o sites- Crosses blood brain barrier
Buzea et al, 2008
Nayak et al, 2010
• Coatings (Derfus et al 2004)– Hepatocytes exposed to CdSe quantum dots:
• 66% viability - coated with ZnS• 6% viability – uncoated
• Agglomeration – “Differential protein adsorption”
Metal nanoparticles• Silver – antimicrobial in both ancient and
recent history• Heavy metals• LD50:
nanoparticle macroparticle
Gold > 5g/kg (50nm) > 5g/kg rat
Silver > 2g/kg 2.8g/kg (AgO) rat
TiO2 >12g/kg >24g/kg rat
Cu 0.41g/kg (23.5 nm) >5g/kg (17um) mice
Se 0.13g/kg 0.02mg/kg (NaSe) mice
Botulism toxin 1 - 3ng/kg human
Control Ag-starch Ag-BSA
24 h post-fertilisation (5ug/mL)
72 h post-fertilisation (100ug/mL)
Asharani et al, 2008
Carbon Nanoparticles
• Different conformation of nanostructure in arrangement of carbon ring structures.
• Discovered in 1991.• Fullerene ring structure• Nanotubes• Nanospheres• Nanofibers
Carbon Nanotubes
• Cylindrical nanostructure in arrangement of carbon nanotubes.
• High tensile strength, electrical conductivity, high ductility, high heat conductivity, chemically inactive.
Nanospheres
• Buckminsterfullerene configuration.• Smallest fullerene and most abundant in nature.• Hollow spheres that have vast application
capabilities.
Nanofibers
• Cyclic nanoparticles with graphite layers.
• Can aggregate into cylinders and form nanotubes.
Health Hazards
• Carbon nanoparticles enter cytoplasm and cause cell death.
• Similar to asbestos fibers and can cause pleural mesothelioma or peritoneal mesothelioma.
Toxicological Studies
• Inhalation toxicity of multi-walled carbon nanotubes in rats exposed for 3 months.
Ema et al. 2010
Nanoparticles in the News
• 17 year old discovers nanoparticle that detects and kills cancer.
• Nanoparticles that boost immune response and strengthens immune system.
• Nanoparticle solar cells make light work.
Conclusions
• Naturally occuring nanoparticle regulations in the future.
• Anthropogenic nanoparticle use in future cancer treatments.
• Tighter regulations in development to reduce environmental effects.
References• Ball, Phillip. "Nanoparticle solar cells make light work." Nature News [New York] 3
Nov. 2011: 1-2. Print.• Buzea, Christina , Ivan Pacheco Bladino, and Kevin Robbie. "Nanomaterials and
nanoparticles: Sources and toxicity." Biointerphases2.4 (2007): 1-88. Print.• De Jong, Wim, and Paul Borm. "Drug Delivery and Nanoparticles: Applications and
Hazards."International Journal of Nanomedicine2.3 (2008): 133-145. Print.• Heimbuch, Jaymi. "Carbon Nanotubes in Environment Affect The Growth of
Algae." Discovery [USA] 4 Nov. 2011: 1. Print.• "Nanoparticle trick 'boosts body's vaccine response'." BBC News Health[Britain] 22
Jan. 2012: 1. Print.• Oberdörster, Eva, Gunter Oberdörster, and Jan Oberdörster. "Nanotoxicology: An
Emerging Discipline Evolving from Studies of Ultrafine Particles." Environmental Health Perspectives 113.7 (2005): 823-836. Print.