This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
1
Nanotechnology Nanotechnology & &
Risk AssessmentRisk Assessment
Sirasak Teparkum, Ph.D.Director of Academic
& Technology Transfer Division
National Nanotechnology CenterNational Science and Technology
Development Agency
OutlineOutline
• What is nanotechnology?• Nano in nature• Quantum effect in nanoscale• The dilemma of nanotechnology• Safety issues of nanotechnology• Toxicity of nano-materials • Who is NANOTEC?• Roles of NANOTEC
“First time in the world history of atomic-level writing in Thai letters, formed by 50 carbon monoxide molecules on the surface of copper (Cu 111)”--- achieved by IBM and National Nanotechnology Center
“The most prevalent nanomaterials used in consumer products”
1. Nanosilver
Silver (bulk): Toxic to fish, algae and crustaceans, some plants and fungi
Nanosilver: Toxic (in vitro) to mammalian liver cells, stem cells and brain cells
Colloidal silver ingestion: Neurological problems, (micro and nano) kidney damage,
GI upset, headaches, fatigue, skin irritation
Toxicity: Nanosilver >> Silver (bulk) or other heavy metals
Acute toxicological effects of zinc nanoparticles in vivo
• In mammals, Zn is an essential metal for DNA synthesis, cell growth and division, membrane metabolism and brain development etc.
• In human, the requirement of Zn is recommended as 10-20 mg/day• Zn deficiency cause a variety of disorder• High dose of Zn oral administration (2-8 mg/kg/day) results in GI damage,
N/V, abdominal cramps and diarrhea
Background
Micro-Zn: 5 g/kg/day• average size 1.08μm
ExperimentMice• CD-ICR strain, both sexes, age 5 wks• Oral gavage for 14 days
Wang B et al., 2006 Tox Lett 161:115-123
2. Zinc Nanoparticles
Nano-Zn: 5 g/kg/day• average size 58 nm
10
Blood Biochemical Parameters
Group ALT (U/L) AST (U/L) ALP (U/L)
Micro-Zn 25.4* 77* 119*
Nano-Zn 23.7* 67 119*
Control 17.8 57 91
Liver function tests : AST = aspartate aminotransferase, ALT = alanine aminotransferase, ALP = alkaline phosphatase* P<0.05 vs control
(5 g/kg)
(5 g/kg)
Wang B et al., 2006 Tox Lett 161:115-123
Control
Micro-Zn
Nano-Zn
Renal pathological examination
Arrow Glomerulus swelling
Circle area Proteinaceous casts in renal tubular
Kidney from mice exposed to zinc powder at a dosage of 5 g/kg on 14 days
Wang B et al., 2006 Tox Lett 161:115-123
• Liver damage was probably induced by both micro- and nano-Zn
• Renal pathological examination: Severe renal lesions were found in nano-Zn mice
• Nano-Zn could cause severe anemia
• Slight stomach and intestinal inflammation was found in all Zn-treated mice
Summary
Wang B et al., 2006 Tox Lett 161:115-123
Acute toxicological effects of copper nanoparticles in vivoChen Z et al., 2006 Tox Lett 163:109-120
• Copper is essential micronutrient• In human body copper is maintained in homeostasis• Copper toxicity results in hemolysis and liver and kidney damage
Background
Micro-copper• average size 17μm• Specific Surface Area (SSA) 3.99 x 102 cm2/g
ExperimentMice• ICR strain, both sexes, age 8 wks,• Single oral gavage, tissues: collected 48 h after dosing
Nano-copper• average size 23.5 nm• Specific Surface Area (SSA) 2.95 x 105 cm2/g
3. Copper Nanoparticles
Blood Biochemical Parameters
Group BUN (mmol/L) Cr (μmol/L) ALP (IU) LD50 (mg/kg)
Micro-Cu 8.0 49.0 92 >5000
Nano-Cu 14.3* 66.0* 186* 413
Control 8.8 51.8 112 NA
Renal function tests: BUN= Blood urea nitrogen, Cr = CreatinineLiver damage: ALP = Alkaline phosphatase* P<0.05 vs control
(734 mg/kg)
(736 mg/kg)
Chen Z et al., 2006 Tox Lett 163:109-120
Pathological Changes in Kidney
Nano-Cu exposed mice exhibits dramatic changes in color and become bronze-colored
Chen Z et al., 2006 Tox Lett 163:109-120
Pathological Changes in Spleen
Nano-Cu particles cause severe atrophy and color changes
11
• The difference in size of Cu particles alteredbiological effects
• Comparison of toxicity/biological activity should be based on SSA
• Kidney, liver and spleen are found to be target organs of nano-Cu particles
• Toxicity of nano-Cu is also gender-dependent:male mice exhibit more severe toxic symptom
Summary
Chen Z et al., 2006 Tox Lett 163:109-120
Environmental Risks• Bind to soil and sediment particles
Environmental Risks• Bind to contaminating substances :
possible of transporting pollutants in groundwater
Environmental Risks
• Nano zinc and titanium washed off from skin may aggregate to larger mass : reduce potential microbial activity
Environmental Risks
• Longevity of particles : effects on other species