TC-1 Tissue Chopper
EMS Catalog #93100
The TC-1 Tissue Chopper Is Designed To Facilitate Cutting Of 100-1000 Micron Thick Brain Tissue Slices For Use In Recording Experiments. The Chopper Includes A Guillotine Arm With Adjustments To Assure Blade Alignment. The Brain Sample Is Moved With Respect To The Arm With A Stage Whose Position Can Be Read With 2 To 3 Micron Precision On A Digital Micrometer Scale. The Stage Is Made With A Removable "PTFE" Surface Plate To Facilitate Cleaning.
Mounting The Blade
Note: Always move the Guillotine Arm using the handle at the end of the arm! Mount the blade with the Arm in the "up" position with Stop Pin In.
Gillette double-edge "Super Blue" Blades are recommended for use with the TC-1. The blade is mounted by removing the two cap screws holding the plate on the Guillotine Arm (Please refer to Figure 1). Loosely tighten the mounting screws. (Precise alignment will be described in section 2).
Aligning the Blade
The Arm has two adjustments for positioning the blade:
- Height: the screw on the top of the arm adjusts the height of the blade from the cutting surface by stopping it just before it contacts the surface. To adjust, loosen the wing nut, and turn the screw. To secure, tighten the wing nut without turning the screw.
- Orientation: The orientation of the blade with respect to the cutting surface can be adjusted by turning Adjustment Nut causing the arm to pivot on the Height Adjustment Screw.
To precisely align the blade for operation, place a small section of moistened filter paper on the cutting surface. After mounting the blade, remove the Stop Pin, carefully lower the Guillotine Arm and advance the height adjustment screw so the blade will be well above the cutting surface when the arm is all the way down. Now turn the Height Adjustment screw so the blade is lowered toward the filter paper (the blade mounting screws should be slightly loose at this point).
Continue to lower the arm with the screw allowing the blade to contact the filter and "level" itself squarely with the filter paper surface. Backlighting the blade will aid in seeing if the blade is leveled. Carefully tighten the wing nut without turning the height adjustment screws. Then carefully tighten the blade mounting screws. The blade should now be aligned. If the arm is dropped from a height of about 5cm the blade should cut the paper uniformly.
If the blade cannot be leveled against the cutting surface, loosen the Tightening Nut and turn the Adjustment Nut until the blade is parallel with the surface. To secure, hold the Adjustment Nut and tighten the Tightening Nut.
Readjust the Blade Height Screw if necessary.
Preparation of the Blade
Just prior to use, the blade should be cleaned carefully with ethyl alcohol or acetone and then rinsed with distilled water to remove oil and accumulated dust. A fresh blade should be used each day. If blades are reused, build-up may hamper precise slicing of the tissue. Many investigators change blades after each preparation.
The tissue sample should be placed on moistened filter paper rather than directly on the "PTFE" cutting surface. The filter paper helps hold the section and prevents the blade from marring the "PTFE" surface.
When slicing, position the tissue so that it is just to the right (looking down) of the blade when the micrometer reads 15.00 mm. Rotating the cylinder clockwise will cause the numbers to decrease and move the tissue under the blade.
The scale on the micrometer reads in .01mm increments. A third decimal place can be extrapolated to approximately .003mm precision (3 microns). This extrapolation is usually not necessary since slices for most applications are approximately 200 to 500 microns (.2 to .5mm).
Mounting and Slicing the Tissue
To prepare tissue slices, position the tissue section on a piece of moist filter paper on the cutting surface. Place the section in such a way that the slice will be oriented correctly. It is important to keep the tissue moist with frequent application so media during the slicing.
Remove the stop pin and DROP the arm onto the tissue. The cutting action is accomplished with a quick, sharp drop of the guillotine arm from a distance of approximately 40-50mm.
The tissue slice will adhere to the blade and is best removed by using a 00 or 000 sable artist's brush. Raise the arm slowly to avoid pulling the remaining tissue section up with the blade. Note the micrometer setting and advance the tissue by rotating the micrometer cylinder to produce the required tissue slice thickness.
Slices should be transferred to a petri dish (usually at a temperature lower than room temperature) containing a balanced salt solution. Make certain slices are not folded over or lying on top of each other.
When the required number of slices has been prepared, remove the filter paper with the remaining tissue and discard.
- As described above, the blade should be discarded after each day's use.
- Thoroughly clean the "PTFE" plate after each use. If it has been damaged or deformed, it can be removed and a replacement ordered.
- It is important that excess media be cleaned from the slice mechanism and not be allowed to accumulate. It may be necessary to periodically rinse the mechanism thoroughly with a soapy solution followed by distilled water and alcohol rinses. Very light machine oil should then be applied.