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Electron Microscopy Protocols

Microwave Tissue Slice Processing Checklist          Sample:___________________

Osmium-based chemistry for up to 6 micro-

centrifuge tubes                                                  Date:_____________________

PELCO 3451 Microwave   Oven                             

Power controller

Cold spot device and vacuum chamber

Load cooler at 30oC setting

Acetone Dehydration

Epon Resin                                                           Standard Epon

 

 

Temperature Restriction Set Point

Processing Time in Microwave

Processing Time Outside Microwave at Room Temp.

1. 0.1 M Cacodylic Buffer Rinses

 

 

 

3-4x (can be stored overnight at RT)

2. Reduced Os - UNDER vacuum

Ø       Mix vial 1 (1.5 mls of 4% OsO4 (aq) and 1.5 mls of 0.2 M cacod.) with vial 2 (1.5 mls of 6% KFeCN (aq) and 1.5 mls of 0.2M cacod.).

Ø       Microcentrifuge tubes

Ø       Cool samples below 15o C

Power level = 100-175 W

37o C

 

 

 

1X or 2X

__ 1 min ON, __

__ 2 min OFF, __

__ 1 min ON __

 

Pre-cool before each session

 

3. 0.1 M Cacodylic Buffer Rinses

 

 

5x at 1-2 min each

4. 1% Osmium - UNDER vacuum

Ø       Mix 1.5 mls of 4% OsO4 (aq), 1.5 mls water, and 3 mls of 0.2M cacod.

Ø       Cool samples below 15o C.

Power level = 100-175 W

37o C

 

 

 

1X or 2X

__ 1 min ON, __

__ 2 min OFF, __

__ 1 min ON __

 

Pre-cool before each session

 

5. 0.1 M Cacodylic Buffer Rinses

 

 

5x at 1-2 min each

6. Water Rinses

 

 

2x briefly

7. 1% Uranyl Acetate (aq) – UNDER vacuum

Ø       Cool samples below 15o C.

Power level = 100-175 W

37o C

 

1X or 2X

__ 1 min ON, __

__ 2 min OFF, __

__ 1 min ON __

 

Pre-cool before each session

 

8. Water Rinse

 

 

2x briefly

9. Acetone Dehydration

Do Not Use Vacuum!!!

Ø       Change to processing baskets

·   50% acetone     2X

·   70% acetone

·   90% acetone

·   100% acetone   3X

   Power level = 250 W

37o C

40 sec __ __

40 sec __

40 sec __

40 sec __ __ __

 

 

10. Resin Infiltration – UNDER vacuum

Ø       1:1 Acetone to Epon

Ø       1:4 Acetone to Epon

Ø       100% Epon 3X

Power level = 350 W

45o C

3 min __

3 min __

3 min __ __ __

 

 

For coffin molds or BEEM capsules:

11. Polymerization

Ø       use fresh 100% Epon

 

 

 

60o C oven, embed in molds, cure for 48 hours

12. Optional for coffin molds:

Ø       Re-surface block with fresh Epon on Aclar at 24 to 36 hours into the 48 hour 60oC curing session.

 

 

60o C oven, embed in Aclar, cure for at least 12 hours

 

Last Updated: 5/01/03