Lecture 14 Toxicology of Nanoparticles

Question 1

Define nanoparticles.

Answer 1

Particles with at least one dimension smaller than 1um

Question 2

Nanoparticles have ____ surface area, and hence ___ reactivity.

Answer 2

Larger surface area, greater reactivity

Question 3

Name some natural nanoparticles.

Answer 3

Viruses (infectivity), soot, dust

Question 4

Name engineered nanoparticles used in common products.

Answer 4

Ag nanoparticles in clothing and medical bandages

Question 5

Which type of nanoparticles are of concern and are not? (hint: mobilisation)

Answer 5

Not of concern: nanoparticles immobilised within bulk material
Of concern: nanoparticles capable of mobility within the environment or in a heterogeneous environment (mixed in liquids or gas)

Question 6

What are some physicochemical properties that characterise nanoparticles?

Answer 6

Size, shape, surface chemistry/charge, aggregation, crystal structure, stability over time, dosing metric, uptake.

Question 7

What characteristics affect nanoparticle dosing?

Answer 7

Estimate of surface area = #particles + size + shape.
Aggregation and stability.
The softness or hardness of the nanoparticle.

Question 8

What establishes when nano materials are placed in a biological environment?

Answer 8

Nanoparticles become surrounded by biomolecules such as proteins which attach onto the surface forming a bilayer called ‘corona’.

Question 9

Does the corona affect reactivity?

Answer 9

Yes, the active material is now the nanoparticle-plus-corona, corona defines physicochemical properties.

Question 10

How do nanoparticles enter tissue/organs?

Answer 10

Circulatory system or lymphatics

Question 11

How do nanoparticles enter cells?

Answer 11

Endocytosis, no receptor required, envelope with membrane.

Question 12

What is the most common target cell of nanoparticles?

Answer 12

Alveolar epithelial cells to enter respiratory system

Question 13

What are some chemical interactions between nanoparticles and cells?

Answer 13

Production of reactive oxygen species.
DNA damage
Release of toxic ions
Disturbance of cell membrane potential

Question 14

What are some physical interactions between nanoparticles and cells?

Answer 14

Disruption of membrane
Disruption of transporters
Protein aggregation
Protein misfolding

Question 15

What are common effects of membrane disruption by nanoparticles?

Answer 15

Intracellular homeostasis disruption, can lead to cell death

Often target mitochondria

Question 16

What are functional assays?

Answer 16

Investigates the effects on various cell processes

Question 17

What causes Ag nanoparticle toxicity?

Answer 17

Release of Ag+ ions

Question 18

How does a DNA comet assay work?

Answer 18

Cells with damaged (relaxed) DNA having single-strand / double-strand breaks. Cells embedded on agarose gel, after electrophoresis, damaged DNA will be separated from intact DNA generating a comet ‘tail’

Question 19

What are carbon nanotubes used for?

Answer 19

Drug and gene delivery vehicles and as scaffolds for tissue engineering.

Question 20

Which type of carbon nanotubes cause most severe adverse effects?

Answer 20

Long fibre asbestos protrudes the whole cell of phagocyte, unable to digest, so have to recruit giant cell. This is exacerbated if the fibre is tangled.