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WHAT ARE NANO-PARTICLES 1-100nm
Unique Properties Sun-screens Baby powders Food packaging
High surface area to volume ratio
CARBON NANOTUBES Cylindrical mesh structure
Single and Multi-walled
Surface impurities
Diameter in nano-range
NANOTUBE TOXICITY Structural Differences
Madani et al. – high aspect ratio = more toxic
Bottini et al. – functionalised = less toxic
Koyama et al. – metal impurities = more toxic
SERTOLI CELL “Nurse Cells”
Phagocytic Role
Role in Blood:Testis Barrier Maintenance
Separates developing sperm from immune system
RELEVANCE Declining Sperm Quality
Carlsen et al. – 50% decrease in 50 years 1940-1990
Many believe trend due to environmental toxicants
(Evidence is however somwhat disputed)
AIMS Develop the TM4 cell model
“To investigate the toxicty of various forms of multi-walled CNTs on murine Sertoli cells”
SO, WHAT DID I DO? Cultured primary TM4 cell line
Seeded 96 well plates
Treated with MWCNT
Conducted WST-1/Alamar Blue viability assay
0 0.125 1.25 12.5 25 50 100 2000
20
40
60
80
100
120
Coiled Vs Straight CNT Relat-ive % Viability
Coiled % viability Straight % viability
0 0.125 1.25 12.5 25 50 100 200020406080
100120140160
CNTs +/- Iron % Viability
Without Iron % viabilityWith Iron % viability
THE STATS No iron resulted in p=0.011
Due to high error, 200 sig from 1.25 and 50
Iron resulted in p=0.259 Standard Deviation as high as 75%
SO, WHAT DOES THIS SHOW Straight MWCNT more toxic than Coiled
Yuan et al. showed physical piercing with straight CNTs
Coiled CNTs may behave like larger particles Auffan et al. showed this effect
SO, WHAT DOES THIS SHOW With/Without iron CNTs had large amounts
of error Issues with suspension
No level showed toxicity of NanoAmor CNTs Aspect ratio less than 3:1
Greater toxicity found without iron CNTs with iron rose to highest level above 100%
FUTURE STUDIES Sertoli and Leydig Co-culture
Sertoli/Leydig co-culture shows increased cell activity
Animal model Ability of CNTs to cross into testis Accumulation Toxic effects Sperm quality Investigate effect of site of exposure Generational study