Frequently Asked Questions

Q: What kind of embedding medium should I use?

A: We use 2% agarose to embed the brain tissues.

Q: Can multiple small samples embed at the same time and cut together?

A: Yes. But don’t cut the sample too small to avoid the individual slice falling off from the large agarose slice after sectioning.

Q: What kind of fixation medium should I use?

A: The brain tissues can be fixed with 4% paraformaldehyde or 10% neutral buffered formalin.

Q: What kind of buffer to use when cutting fixed brain slices?

A: Phosphate-buffered saline (PBS) is used for slice cutting.

Q: How to store the original fixed sample? How about the slices samples?

A: The fixed tissue can be stored in 4°C for several days. The fixed tissues in anti-freeze buffer can be stored in -20°C (up to 20 years).

Q: Can sample be Freeze and thaw?

A: Please avoid freeze and thaw of brain tissues to keep the high quality of the tissue histology.

Q: How do I make slices at different angles?

A: With the VF-200 and VF-300, we use a metal tube to embed the tissue blocks, and then use a plunger to push the tissue out through the tube. You can think of the front of the plunger as the platform that you put your tissue on. You would cut your tissue according to the angle that you would like to slice, and then glue that block on the plunger. If you would like to have slices at 45 degrees from the horizontal, you should block your tissue so that the base that you are gluing to the plunger is 45 degrees.

Q: Would the temperature fluctuations from agarose embedding cause damage to the cells?

A: It is true that there is some temperature fluctuation during the embedding process. But what we found is that the embedding allows us to dramatically slow, and sometimes eliminate the knife’s vibrating frequency, greatly reducing the mechanical stress on the slices.
In addition, we will be providing you with the tools to make this temperature fluctuation as mild and as quick as possible. Here is how we do that:

1. We provide a brass block with a hole in the middle that fits the embedding tube snugly. You first place this block on ice to chill it.

2. Melt the agarose (with gel point at 37 degrees Celsius), and then bring it down to around 39 to 40 degrees in a water bath.

3. Pipette the agarose into the specimen tube.

4. Put brass block around the tube to chill the agarose and the tissue down to the pre-embedding temperature within a few seconds.

Q: How many specimen tube sizes do you have?

A: There are three different tube sizes for the VF-200 and VF-300 series. They are standard size (12.5 mm), large size (15.5 mm) and small size (6 mm in diameter). You should choose a tube size that is the closest to slicing needs for the best results. The standard tube is good for mouse and young rat brains. The large tube is good for adult rat brain.

The specimen tube size for the VF-700 are 17 and 22 mm in diameter. There are ftwo specimen tube sizes for the VF-800. They are 70 and 100 mm diameter tubes. You can only choose one tube size for each machine.

Q: Do you have a way to control the buffer bath temperature?

A: We currently do not have a temperature regulator to control the buffer bath temperature. Our microtome slices at a fairly efficient speed that it can finish slicing your tissues within a few minutes. Using an icy bath is enough to maintain the tissue temperature during this period of time.

Q: Can I use this to cut tissues other than brain?

A: Besides cutting brain tissues, you can use the Compresstome to section most of the soft animal tissues, such as liver, kidney, lung, heart, skeletal muscle, pancreas, retina, skin and aorta. You can also use the machine to section soft plant tissues.

Q: What’s the difference between the VF-200 and the VF-300?

A: The VF-200 is the semi-automatic model with a slice thickness resolution of 10 microns. You have to manually advance the tissue through the tube with the micrometer. Thus, it is suitable for slicing live tissues for electrophysiology and tissue culture where the thickness requirement is 150 micron and up.
The VF-300 is a fully automatic model with a slice thickness resolution of 1 micron. It has a digital control that advances the tissue with extreme accuracy. The VF-300 also has a continuous slicing mode in which you can set the per-slice thickness and hit the start button. The microtome will cut all of the slices for you. Due to this additional precision and automation, the VF-300 can be used for cutting fixed tissues for immunohistochemistry as well as cutting live tissues.

Q: Why do you have a vibrating setting where the blade doesn’t vibrate at all?

A: With our patented technology, we find that we can turn off the vibration when slicing tissues of younger animals that are less fibrous. The elimination of the vibration further reduces mechanical stress from the tissue slices, making much healthier slices.

Q: When do you recommend slicing at a warm temperature?

A: We recommend slicing brain slices in warm temperature for animal younger than P25. Warm slicing eliminates the temperature shock and speeds up slice recovery. During temperature shock, cells will depolarize and fire action potentials which loads the cell up with Na+ and Ca2+.

Q: Why should I use your slicer to cut my fixed tissues over a cryostat?

A: Our microtomes have a number of advantages over cryostat, as described in theimmunohistochemistry section. Its simpler protocol, stronger signals, consistent slice thickness, better histology image, and ease of use are just some of the reasons why the VF-700, VF-700 are preferrable for free-floating section immunohistochemistry.

Q: I am very excited about your slicer, how do I get one?

A: You can email us at [email protected] to request a quote. We do not have a demo program at this point. However, we are so confident of our vibratory microtome’s capability that we are offering a 3 month full refund policy so that you can try it for three months risk free to ensure that it will work in your lab. When ordering, please indicate the size of specimen tube for your machine. There are two specimen tube sizes. The standard size is 12.5 mm in diameter which is good for young rat (younger than P40) and mouse brains. The large size is 15.5 mm in diameter, suitable for embedding the entire adult rat brain.

Q: What is the cutting range/ thickness for the VF-900?

A: The cutting range of the VF-900 is from 40 um (minimum) to 500 um (maximum) in slice thickness.

Q: Can Compresstome VF-900 be used on acute brain tissues?

A: No. The embedding process takes too long for acute tissues.

Q: Can I chill the buffer tank during sectioning?

A: Yes, you can. You can use an icy buffer for slicing tissues, or place ice or ice packs around the buffer tray to keep the entire tray cold.

Q: Is the buffer tank removable?

A: At this time, the buffer tank is not removable. But we are actively designing a new model with removable buffer tanks!

Q: What glue should I use for stabilizing the tissue I want to cut?

A: We highly recommend using the Instant Krazy Glue that is commonly used in labs. The glue comes in a red/green vial with a control tip applicator. It is best to avoid gel-like glues because the consistency of those products could damage the tissue during the glueing process.