LEcture 5

Question 1

In Biology how is the sample thinned?

Answer 1

Typically using a microtome which cuts the sample to 50-100nm however you can also use FIB or a cyromicrotome.

Question 2

What is immunogold labelling?

Answer 2

Using a secondary antibody labelled with gold particles

Question 3

How are the holes made in a holey carbon grid?

Answer 3

Irradiating the C with a strong beam

Question 4

Why not freeze with liquid nitrogen?

Answer 4

A gas layer forms around the sample, the thinner the sample the smaller the gas layer. This gas layer leads to crystal formation as the sample is not frozen instantaneously.

Question 5

How is a sample cut with FIB?

Answer 5

A focused beam of Galium ions dissociates injected tungsten or platinum ions to protect the lower areas. This then undergoes cutting via FIB to create a lamella. The lamella can be picked up using a sharpened glass wire. `

Question 6

How is the sample thinned using chemicals?

Answer 6

Add acid so that it creates a hole. This will create areas of thin wedge shaped sections