Frequently Asked Questions about slicing machines
Q: Which machine is the best for adult brain slice?
A: We currently advocate the use of the Compresstome (VF-200) from Precisionary Instruments. We have used the Vibratome (now Leica) 1000, the Leica VT1200S with vibrocheck, and the Precisionary Instruments Compresstome VF-200 all with excellent results. There are several features of the Compresstome VF-200 that make this slicer particularly well-suited for acute brain slice from adult and aging animals. (1) The speed of slicing is about 2X faster than the other models. This is possible because of the agarose embedding and slight compression of the tissue as it contacts the blade edge, leading to very uniform section thickness. (2) This machine also allows uniform thin sections to be prepared from live tissue at as little as ~100-150 micron thickness, which may be advantageous when examining densely myelinated regions where visualization is more difficult. (3) The Compresstome VF-200 has a very small footprint on the lab bench and can be easily moved or transferred between rooms or lab sites. (4) The cost of the Compresstome VF-200 is about half the cost of the top-of-the-line Leica VT1200S, and the cost of maintenance is also much lower by comparison. (5) We observe excellent preservation of neurons in the first few cell layers beneath the cut surface in areas such as CA1 of hippocampus with the protective recovery method. This empirically demonstrates a very minimal Z-axis vibration with the Compresstome VF-200, and this is surprisingly comparable to the performance of a vibrocheck-calibrated Leica VT1200S. Note that the choice of machine can have more of an impact on the results when using the traditional protective cutting method of slice preparation.
Q: What is the best blade for cutting adult brain slices?
A: Tissue compression is a major issue when slicing adult brain tissue with mature white matter. To avoid compression and create a smooth cut surface some people have used freshly broken glass blades (which are very sharp but difficult to make consistently) or sapphire blades (which are sharp and uniformly manufactured, but are fragile and cost between $150-450 each). We have had excellent success with a custom blade made of zirconium ceramic, which yields a super sharp edge and is extremely durable. These blades can be purchased at specialtyblades.com (now redirects to a company called Cadence), part number EF-INZ10. A pack of 10 blades will last a year or more at a cost of about $15 per blade. These work on all typical slicing machines and can be used repeatedly over many weeks or a few months with consistent results. The ability to reuse the blades provides an important simplification in using the Compresstome as this precludes the need to remove, clean, and re-attach a new blade each day--a process that can be cumbersome.
Q: How durable is the Compresstome and how good is the customer service?
A: The Compresstome has very few working parts and is in many ways a very simple but effective machine. This can be advantageous because the cost of parts for replacement is generally much lower than for more complicated machines, and the chances of a catastrophic failure are much lower. There are two main ways to damage the Compresstome: (1) running the blade into the metal 'lipstick' holder due to improper alignment or failure to check the alignment before use. This can damage the moving arm so that the movement becomes jerky or slips across regions and requires immediate repair. (2) rust can build up on the micrometer of the manual model VF-200 if solution is allowed to contact the parts and is not properly cleaned off. Care should be taken to avoid rust as it can compromise the slice integrity if any enters the bath and will seize up the micrometer over time. In cases where we have encountered such problems, the company was very prompt at repairs and returning the machine to perfect working order. As a side note, the use of NMDG aCSF avoids the problem of sticky sucrose aCSF jamming up the working parts of the slicing machine, and this is true for any slicer model.
Link to 'Compresstome' website
Link to 'Specialty blades' website