P40 Technique

Question 1

What is the P40 solution derived from?

Answer 1

P40 solution is derived from Biodur® polyester resins

Question 2

What is the P40 technique mainly used on?

Answer 2

P40 technique is mainly used on brain slices

Question 3

What does the end result of the P40 technique have and what type of brain is suitable for the P40 technique?

Answer 3

 The end results has a degree of transparency.

 Formalinised brain is quite suitable for this type of plastination

Question 4

Composition of the P40 solution:

Answer 4

 E12 (plastination fluid)
 E1 HARDENER
 AE10 (plasticisor)
 AE30 (glass separator)

Question 5

Preparation of the specimen

Step 1:

Answer 5

Cut brain slices of about 3mm thickness using a bacon slicer.
The slices could be cut in horizontal, coronal or sagittal plane

Question 6

Preparation of the specimen

Step 2:

Answer 6

Each slice is carefully placed in plastic grids and stabilized with ties

Question 7

Preparation of the specimen

Step 3:

Answer 7

Leave in a container under running tap water for 24 hours to wash off the formalin

Question 8

Preparation of the specimen

Step 4:

Answer 8

Brain coated with gelatin and allowed to set before slicing may
prevent ‘fraying’ of neural tissue during slicing

Question 9

DEHYDRATION PROCESS

Steps 1 & 2:

Answer 9

 Dehydration is best done at a temperature of -20°C to minimize
shrinkage

 Immerse the slices/specimens in 20% acetone solution

Question 10

DEHYDRATION PROCESS

Steps 3 & 4:

Answer 10

 The concentration of acetone is gradually increased in units
of 10% until 100% is reached

 This process takes between 6 – 10 weeks

Question 11

FORCED IMPREGNATION

Steps 1 & 2:

Answer 11

 P40 solution is prepared

 The specimen is immersed in a container filled with P40 solution and
placed in a vacuum tank set at a negative pressure of -1KPL

Question 12

FORCED IMPREGNATION

Step 3:

Answer 12

 The presence of bubbles in indicative of acetone being replaced
by P40 solution in the specimen

Question 13

FORCED IMPREGNATION

Step 4:

Answer 13

 The specimen should be left in the vacuum tank until bubbles
cease to form, indicating that the tissue is now fully impregnated

Question 14

EMBEDDING AND CURING PHASE

Step 1:

Answer 14

Specimens are placed in a double glass held by clamps and separated by a gasket

Question 15

EMBEDDING AND CURING PHASE

Steps 2 & 3:

Answer 15

 P40 solution is poured between the glass plates to submerge the specimens

 The upper end is sealed and is ready for curing

Question 16

EMBEDDING AND CURING PHASE

Steps 4 & 5:

Answer 16

 Curing occurs by exposing the specimen in ultra-violet light

 Specimens are exposed to ultra-violet light and hardening is complete
within 48 hours

Question 17

EMBEDDING AND CURING PHASE

Step 6:

Answer 17

Place the specimen in an incubator at 40°C for a further 12 hours

Question 18

EMBEDDING AND CURING PHASE

Step 7:

Answer 18

On removal from the incubator there should be signs of separation

Question 19

EMBEDDING AND CURING PHASE

Steps 8 & 9:

Answer 19

 Remove the clamps and trim and polish the edges of the cast of the cast of the embedded specimen

 They are ready for museum display