Delong LVEM5 and LVEM25 low-voltage transmission electron microscopes for life science

Electron microscopy is an important tool in the world of life scientists, enabling cell biologists and neurologists to visualise tissues and cells. The microscopes are being used in pathology to better understand the molecular mechanisms of disease, while virologists use these tools to observe individual viruses and virus-like particles. The technique is also required in the design and testing of novel biomaterials as well as in drug discovery and delivery.

These samples types are normally a major challenge to image in an electron microscope due to inherent low contrast provided by their molecular composition. This is not the case when using either the LVEM5 or LVEM25 microscopes in life sciences applications, as issues with sample contrast are eliminated entirely.

Low-energy electrons, as found in the LVEM5 and LVEM25, are said to interact much more strongly with the sample than high-energy electrons of classical TEM. In the case of LVEM, electrons are strongly scattered by organic materials, resulting in differentiation of features. The density difference required in a sample to give a 5% contrast difference at 5 kV is just 0.074 g/cm³.

The low accelerating voltage — 5 kV for the LVEM5 and 25 kV for the LVEM25 — gives the systems the ability to provide high-contrast results with no addition of contrast-enhancing staining procedures. Although there are instances where staining is desirable for diagnostic purposes, the necessity to stain samples in order to generate adequate detailed contrast cannot be viewed as advantageous.

The LVEM25 system is suitable for working with conventionally prepared specimens (thicknesses around ~100 nm) and allows for staining as an option. For both the LVEM5 and LVEM25, a high-contrast result can be acquired from samples in their inherent, natural state. This provides images without the side effects often encountered such as staining artefacts or the sample crashing out by chemical reaction with heavy metals.