Nanotoxicology Flashcards

1
Q

Why are there concerns that nano materials have adverse health effects

A

Because of nanoparticles in environment that cause cardiovascular effects

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2
Q

Where in the lung might inhaled particles deposit?

A

Trachea
Bronchi
Alveoli
Can reach deep into lungs and can cross air spaces and get into vessels

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3
Q

What is the difference between alveoli type 1 cell AT1 and alveoli type 2 cells AT2

A

AT1 cells are stretched, flattened cells.
Cover 95% of alveolar surface.
Used for gas exchange
Susceptible to damage

AT2
5% of cells
Secrete surfactant
Divide and differentiate into AT1 cells 
Involved in alveolar fluid balance and host defence
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4
Q

What % of particles is uptaken by AT1 cells and AT2 cells

A

80% of AT1 cells internalise particles

20% of AT2 internalise

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5
Q

How do AT1 cells take up nanoparticles

A

Engulf the particles by clathrin- mediated endocytosis
Engulfed by clathrin coated pits and fuse with endosome
Can pass through plasma membrane

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6
Q

Describe how to set up an experiment to study bioactivity and toxicity of nanomaterial

A

Obtain cells
Incubate with nanomaterials at increasing dose
Collect medium after a certain time and measure cell mediators eg. Cytokines
Observe cells, look for particle uptake, DNA damage, cell viability

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7
Q

How do cells interact with silver

A

Silver spray products can be toxic, AT1 like cells

Nanofix-
Very toxic even at low conc
Kills all cells so no mediators produced
Diluent stimulates IL6, particles cause death

Mesofix-
Very little effect, combined or alone

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8
Q

How do cells interact with zinc

A

Zinc spray products, AT1 like cells

Therazinc-
Vehicle very toxic, particles less so

Dermazinc-
Particles and vehicle very toxic but less so

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9
Q

How do cells interact with copper

A

AT1 cells - CuO rods and spheres cytotoxic, spindles not

AT2 + macrophages- all shapes cytotoxic

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10
Q

How do cells interact with asbestos

A

Crocidolite - straight, strong, stays in lungs. Induces mesothelioma
Chrysotile - curly, frays, breaks up, cleared from lung. Induces fobrosis

Asbestos very similar in structure to carbon nanotubes

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11
Q

What is the effect of different length nanoparticles on human lung fibroblast activity

A

Short particles are slightly cytotoxic
As you increase length become more cytotoxic
Short particles induce more collagen release = fibrosis

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12
Q

Describe the concern due to similarity of asbestos and carbon nanotubes

A

Carbon nanotubes can exist in many formats
Long fibres of asbestos are worrysome
Can study long and short carbon nanotubes
Long particles can be very cytotoxic in some cell types
Longer C nanotubes more reactive with macrophages
Shorter C nanotubes more reactive with epithelial cells

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13
Q

How does the binding of surfactant proteins A and D to CNTs differ

A

Short particles adsorb surfactant protein A
Less of macrophages have to deal with infection
Could be a protective mechanism to coat CNTs
SPD is taken up by long particles

Bioreactivity of nanomaterials changes depending on location and what they adsorb

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14
Q

How does asbestos affect alveolar cells

A

Long particles have no effect in AT2 cells
But very cytotoxic in macrophages
Frustrated phagocytosis- macrophage engulfs long strand of asbestos

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