History of using diamond knife in ultramicrotomy: In 1950, Latta and Hartmann discovered that the edge of broken glass could be used to cut thin sections of specimen. Glass knives are very popular in ultramicrotomy for trimming specimen blocks and cutting thin and ultrathin sections. A skilled operator can cut a small number of ultrathin sections with a glass knife, while the same operator can use a diamond knife to cut thousands of sections on one area of knife. Some hard specimens and embedding resins (epoxy or acrylate), such as bone, plants, thick-walled spores, metals and ceramics are difficult to cut, even with a good glass knife, because the edge dulls too quickly. In 1955 Humberto Fernández-Morán discovered that a gem-quality diamond could be used to fabricate a more durable knife for use in the ultramicrotomy; diamond was a logical material to use since it was the hardest known material at the time. A diamond knife is a very sharp knife in which the edge is made from diamond.
SYNTEK's excellent technology and skill stand for creation, innovation and invention to provide the best quality and services for diamond processing and superfine processing – in Japan or abroad. SYNTEK's products includes diamond knife for ultramicrotomy and other industrial and scientific applications, such as diamond ball end mill, long life diamond stylus for rotogravure printing, diamond substrate surface polishing, diamond scriber (3points and 4points) for cutting ceramics and glasses, anti-wear Parts (PCD), diamond window (part for laser equipment), diamond indenter (60° Edge Pyramid, Berkovich indenter), Laser Processing (Shaping), Diamond Anvil and cell for making ultra-high pressure, making ice under room temperature (SEED).
Unique features of SYNTEK's diamond knives (SYM knives) :
1.High quality and High stability
2.Hydrophilic treated from the beginning up to 3 years
3.Many years of experience in industrial diamond
4.All products are cutting tested before shipment.
5.Only those that passed are shipped.
Ultrathin section picking up to grid is sometimes difficult especially when you use grid with support film. Carrying out the collection by one hand section tends to escape. MGH boat over-come the collection issues easily and simply by one hand.
Our welding of diamond cutting piece into the knife shank is guaranteed and secured. Our knives can be cleaned thoroughly by washing detergent that contains no ammonia without the risk the diamond cutting edge coming off. Unlike just pressing the diamond and glue it into the shank that will come loose easily upon use and not resistant to chemicals. At the same time the diamond knife boat is uniquely anodized to non-reflecting paint with different colors producing a perfect background for contrasting strong and clear sectioning color to determine ultrathin section thickness. At the same time, we have unique hydrophilic treatment on our diamond cutting edge bringing water to the edge. We don’t need to use acetone any more in your boat water to promote diamond wetting and section, stretching of the sections by decreasing the water's surface tension and softening the plastic.
To obtain a perfect section ribbon, the top and bottom of the block face must be parallel to each other and to the knife edge. If trimming with a razor blade, use a fresh degreased blade and change to a new blade before the final few cuts of your block are made. Avoid taking too thick a cut to avoid damaging the block face.
Do not allow particles from glass pipettes, brushes, razor blades or glass knives to become embedded in the block during processing or trimming. Old razor blades and thick cuts of the block can leave particles behind. When sectioning, these particles damage the diamond's edge. For the same reason, use a clean new portion of a glass knife's edge to complete trimming the block face.
Excessive block width, section thickness, cutting speed or clearance angle increases the potential for chatter and compression because of the increasing cutting force required. Trim block faces as narrow as practical to control the cutting force.
Sectioning - Room Temperature
Good sectioning practice involves incorporating this list of simple rules into your everyday work habits.
1. Align the block face so that it is planar to the cutting arc and the bottom is parallel to the cutting edge.
2. Check that all thumbscrews and clamps are tightened, i.e. the block holder, the knife holder, stage adjustments, etc.
3. Set the clearance angle and cutting speed as listed on the knife box and in the ultramicrotome manual.
4. Set the water level even with the cutting edge and to give a good reflection.
5. Solvents may be added to the boat in any concentration in order to control the surface tension, avoid extraction of specific sample components, etc.
6. Avoid cutting sections thicker than the limits given for each specific knife, since thick sections requiring excessive cutting force may damage the edge. With an ultramicrotome knife, do not cut thicker than 200 nm, 100 nm for very hard blocks. With a Histo-Knife, do not cut sections thicker than 5 microns.
7. Re-approach the knife edge each time the clearance angle, block orientation or knife lateral position is changed or the knife is replaced in the stage.
8. Sectioning partially-cured blocks is the primary source of epoxy debris on the diamond knife edge, a major cause of knife marks on sections. Each block must be fully cured.
9. Be especially careful when moving or collecting sections. Do not touch the cutting edge with any solid object (grids, loops, tweezers).
10. Do not allow sections to dry on the knife edge. Dried sections on the edge are a frequent cause of knife marks and compression.
11. Do not stop block travel or change the clearance angle during a cut or withdraw the diamond knife from a partially cut section. Withdrawal may result in gross edge damage or loosening of the diamond from its metal mount.
Sectioning - Cryo Temperature
Research shows that diamond knives can cut higher quality cryo sections than glass knives. The more durable diamond knife cuts thinner sections with less compression and greater uniformity.
Although the optimum temperature will depend on the specimen being cut, start with these rules of thumb:
>Trimming and semi-thin sections: -60°C
>Ultrathin sectioning of fixed tissue:-80°C to -110°C
>Ultrathin sectioning of unfixed tissue: -120°C
Good sections of fixed tissue are tinged blue or gold, unfixed tissue sections are cellophane-like. Temperatures too high give a soft block and compression, temperatures too low give a hard block and small ice chips. Vary the temperature to optimize your results.
Electrostatic charging in the cryo chamber causes cryo sections to stick to the knife edge, curl, bunch up, and fly away. The lower the temperature, the more pronounced these problems become. If these problems make your cryo sectioning overly difficult, use anti-static ionizer together with our cryo diamond knife.
Cutting good clean sections requires maintaining a clean sectioning environment. Use clean boat fluids while sectioning and reagent grade solutions for cleaning.
Three Step Method
Good habits of knife care will give best results. Use these three steps when sectioning to avoid problems:
1. Before sectioning - Soak the diamond knife edge in a non-ionic detergent, such as Triton X-100, diluted to 0.1% in distilled water. This softens any debris on the edge and improves wetability of the diamond.
2. After collecting sections - Make sure that no sections, or section debris, remain attached to the cutting edge. Using an eyelash, or other flexible fiber, carefully tease section debris away from the edge.
3. After sectioning - Make sure no sections remain on the edge and dump the water out the back of the boat, not over the diamond edge. Rinse the knife with distilled water and carefully wipe the bowl with a tissue (but do not attempt to dry the wet edge of the knife).
Edge Cleaning Devices
Clean the diamond knife edge if epoxy debris is thought to be causing sectioning difficulties. Minimize the use of edge cleaning devices by cutting well-cured blocks and removing section fragments from the edge after sectioning.
A high-density polystyrene rod, available from us, is the safest tool to use for diamond knife edge cleaning. Sharpen it to a chisel edge of 45° using a double-edge razor blade. DO NOT USE DRY. Dip the rod into your cleaning solution and blot on filter paper before use.
While viewing the knife edge under a dissecting microscope, press the chisel end of the stick against the edge of the diamond knife as though to split the stick. Wipe the stick parallel to the cutting edge, never obliquely or at a right angle, across the entire length of the diamond knife edge on each cleaning stroke.
Try distilled water or ethanol first. A 0.1% Triton solution will usually remove any remaining debris. White vinegar is good for truly stubborn cases. Cleaning with the high-density polystyrene stick or by soaking with these solutions is often sufficient. There are other, stronger solutions which can be used in unique situations. If the above solutions do not give the desired results, contact us to learn about cleaning fluids of last resort.
Always rinse with distilled water when finished.
Cryo-Knife Cleaning Tips
Before baking out the cryo chamber, remove the diamond knife. Hold the knife under a stream of distilled water or leave it in a safe place until it has warmed up. Any of the cleaning methods from above can then be used.
Sonication and Acids
Sonication is possible for the cleaning of our diamond knives but strong acids should NEVER be used.