microtome 2.pdf

Dr. Mohammed tawfiq Microtome knives Knives are modelled according to the tissue to be sectioned and the embedding medium. It is the greatest single factor for making good sections. There are many shapes, sizes and materials for microtome knives They were developed...

Dr. Mohammed tawfiq Microtome knives Knives are modelled according to the tissue to be sectioned and the embedding medium. It is the greatest single factor for making good sections. There are many shapes, sizes and materials for microtome knives They were developed to fit certain microtomes and to cope with different degrees of hardness of tissues and embedding media. Can be made of metal or other wise 1} Metal : standard steel & razor blade 2} Non metal : glass & diamond Disposable blades: produce consistently high quality sections and have replaced conventional microtome knives. Provide sharp edge from which 2-4μm thick sections can be cut. Made of high quality stainless steel.  TYPES OF MICROTOME KNIFE A} PLANO CONCAVE KNIFE.  One side of cutting surface is flat and the other is concave with different degrees of concavity.  Extremely sharp, but delicate.  Used for cutting soft samples like nitrocellulose embedded tissues.  The plane surface is closest to tissue block.  Sledge and rotary microtome. A} PLANO CONCAVE B} BICONCAVE KNIFE.  It is the classical knife shape with concavity on both sides  Introduced by Heiffor  Rocking microtome and sledge microtome  Length 100-250mm  Less rigid  Prone to vibration BICONCAVE C} WEDGE KNIFE.  Use in all type of microtome to cut all type of materials  Both cutting surface are plane  Known as standard profile  Size 100-350mm WEDGE KNIFE D} TOOL EDGE / Chisel  Wedge knife with steep cutting edge  Hard object( un-decalcified bone) Have detachable handle (to screw with holder)  Wedge knife is stable for long time  Need more force to achieve the cut  Varying length available  80mm --freezing microtome  240mm-- base sledge microtome TOOL EDGE / CHISEL