Sections for Light Microscopy (0.5-8.0 um thick)

Embedding Material- Paraffin (wax)

Cutting Edge- Steel knife

Sections for Electron Microscopy (50-100 nm thick)

Embedding Material - plastic resin

1. Internal support for thinly-sliced specimen

2. Electron-transparent matrix through which electron image can be projected

3. Resistence to electron beam

Cutting Edge- glass , diamond or sapphire

1. Must retain sharpness while cutting hard material.

Baseline Conditions for Obtaining Good Sections:

1. Completeness of infiltration of specimen with plastic

a. No residual water or acetone should be present at the time of polymerization.

b. No pockets or regions of plastic of heterogeneous consistency should be present- glassy cut surface.

2. Properties of the polymerized plastic

a. Too Hard- shatters Too soft- cheesy

3. Quality of the knife and operation of the microtome

4. Skill of the Microtomist- Developed through practice