The Krumdieck Tissue Slicer, by Alabama Research and Development is one of several tissue slicers intended to be used for generating tissue slices for culture. The slicer is designed so that the tissue cylindrical cores (8 or 10 mm in diameter) are placed into a sleeve that extends down to a cutting stage. The sleeve is then automatically moved over an oscillating stainless steel blade that cuts a slice off the bottom portion of the tissue core at a set depth, all within a buffer-filled slicing chamber. The thickness of the cut can be altered by a graduated knob that adjusts the depth of the cutting platform. Once the core and the plunger (with variable weights) that pushes the core to the cutting stage are in place, the instrument can be activated so that the cutting is done automatically. The control panel on the front of the slicer allows for adjustment of the speed/frequency at which the core passes over the oscillating blade, as well as other fine-tuning of the process such as buffer circulation rate and blade power. Once slices are generated, the circulating buffer drives the slices into a glass slice trap that has a dispensing tube for simplified retrieval. The slicer is robust and is made of heavy duty metal construction. Recent additions to the slicer include various modules and available modifications that allow for greater control of buffer temperature, slice thickness, and aeration/gassing of the buffer.
We have been using the Krumdieck Tissue slicer for a number of years. Once the settings have been adjusted, each core can be placed into the sleeve and the instrument can be activated for automated slicing. This feature greatly reduces the amount of attention the operator needs to devote to the process. Other minor tasks can be undertaken while a core is being sliced. The slice trap can easily be opened to remove slices that have been collected. I also like the graduated knob used for slice thickness adjustment. Once the proper settings (plunger weights and knob setting) have been identified, the slicer will reproduce the same slice characteristics when using the same tissue. The slicer is consistent and produces slices reliably, provided it is maintained properly. The staff at Alabama Research and Development is also very responsive so when problems do arise, they will assist you promptly.
The slicer is made of solid construction but it also has many moving parts and components. The drive motor that generates the motions necessary for slicing causes a lot of vibration and so the screws that hold various parts together may eventually become loose. This requires the slicer to be inspected regularly to ensure that the screws are tightened so that problems during a slicing session can be avoided. This is a minor inconvenience. Also, sterilization of the slicer can be difficult due to the manufacturers’ requirements. The slicing chamber should not be sterilized with alcohol or other organic solvents. The chamber can be baked at 120oC (but not higher!) or autoclaved at 121oC for 15-20 minutes, but you cannot exceed 1.5 psi. I believe that autoclaves normally operate at a higher pressure so autoclave sterilization can be tricky. One apparent design flaw is the use of same metals (steel) for the shaft that lowers the cutting stage and the frame in which it is mounted. Even when soaking the used chamber in water to remove salts from the buffers used in the chamber, repeated use will cause the buildup of salts in the space between the parts. This will cause galling of the materials, causing the two pieces to lock in place. A machine shop was required to separate the parts in our 2 cases and a new shaft was required. Our machine shop finally put a brass bushing in place where the galling occurred both times and the machinist informed me that this should solve the problem.
In summary I would recommend this slicer for labs that are interested in generating slices for culture. The unit is robust enough to handle many years of use, and the Alabama Research and Development staff are helpful. The accessories that are offered should be scrutinized to make sure that they are really needed. Perhaps an appropriately rigged pressure cooker can be used to make sterilization easier.
Holger P. Behrsing, Ph.D.
Toxicologist
Biosciences Division
SRI International
Menlo Park, CA