Found in laboratories, hospitals, and universities worldwide, a microtome blade is a precise instrument that cuts paper-thin sections of tissue for microscopic examination. The quality of these slices can make the difference between clarity and confusion in diagnosis.
Every histological specimen contains crucial information about cellular architecture and pathological changes, but this can only be accurately read if the tissue is cut with absolute precision. Each section must be uniform, often only a few micrometres thick, to preserve the integrity of the sample. If the blade drags, compresses, or tears the tissue, the structure becomes distorted and the section unusable for accurate analysis.
The blade’s performance depends on its edge geometry and the material it is made from. Imperfections in microstructure, such as uneven carbides or inclusions, can cause irregular wear, blunting, or chipping. Microtome blades require a steel with the right hardness, toughness, and corrosion resistance for consistent, smooth sectioning.
A material difference
Among the stainless steels developed for precision blades, Alleima’s 13C26 martensitic grade stands out as a benchmark of performance. Originally engineered for razor blades and other fine cutting tools, this high-purity steel offers a combination of hardness, edge stability, and corrosion resistance.
According to Daniel Larsson, global product manager at Alleima: “13C26 is a martensitic, high-performance stainless steel engineered for extremely sharp and dimensionally stable cutting edges. Its fine carbide distribution provides high hardness and excellent edge stability, which are essential for producing ultra-thin, intact tissue sections without tearing or deformation.”
A homogeneous, fine-grained structure ensures that the steel wears uniformly along its edge, rather than developing weak spots. A stable martensitic matrix prevents micro-cracks, uneven wear, and edge deformation, all of which can compromise performance. This structural integrity allows the microtome to deliver the same level of precision repeatedly, which is an indispensable quality in histology, where thousands of slices may be produced in a single study.
Performance in the laboratory environment
Microtome blades face a demanding environment, regularly exposed to cleaning agents, organic fluids, and moisture. To combat potential sources of corrosion or degradation, 13C26 undergoes heat treatments and alloying processes that enhance its resistance to wear and environmental damage, providing a longer blade life, reduced maintenance, and consistent performance across multiple specimens.
“The steel’s high purity minimises inclusions that could otherwise act as weak points or corrosion initiators,” says Larsson. “Combined with tightly controlled processing and heat treatment, the result is a dense and stable structure that resists wear and environmental impact.”
A microtome blade must also create a clean slice without friction, compression, or tearing. Larsson adds: “In microtomy, surface finish and edge quality are critical. An extremely smooth surface reduces friction and cutting resistance as the blade moves through the tissue.”
This reduced friction makes sectioning easier for the operator. It improves sample quality by providing a smooth surface that minimises tearing, ensuring thinner, more uniform slices and preserving the delicate cellular architecture. An imperfection in edge geometry can cause the blade to push or crush the sample, resulting in errors invisible to the naked eye but devastating under the microscope.
Creating such precision is a feat of engineering as much as it is of metallurgy. The steel used for microtome blades begins as a precision strip that is rolled to exacting standards of thickness, flatness, and straightness. Each parameter must be controlled within fractions of a millimetre, because even the slightest deviation can affect section quality.
After cold rolling, the strip undergoes a customised hardening and tempering process to achieve the optimal martensitic structure. This step is key to achieving both strength and stability. The final stage involves grinding and polishing under carefully controlled conditions to form a flawless edge geometry.
“The material is produced as precision strip steel with extremely tight tolerances,” Larsson explains. “Final steps such as grinding and polishing ensure precise edge geometry and a uniform surface – an absolute requirement for microtome applications where even the smallest deviation affects section quality.”
Looking ahead
As the science behind biomedical research evolves, so too do the demands placed on precision instruments. Automated microtomes, cryostats, and advanced imaging systems all rely on blades that maintain accuracy across a wider range of materials and conditions.
The future of effective microtome sectioning rests upon a precise collaboration between scientific innovation and technical craftsmanship. Metallurgists refine the alloy, engineers translate its properties into functional design, and researchers apply it in practice.
To learn how Alleima can be your partner in microtome blade design, download the whitepaper below.
