Applications

(Left images) a. Lignocellulosic microfibers, b. Lignocellulosic nanofibers, c&d. Quinacridone

(Right images) Mixture of quinacridone and lignocellulose MF: a 2:1 (w/w), b 1:9 (w/w). Mixture of quinacridone and lignocellulose NF: c 2:1 (w/w), d 1:1 (w/w), e 1:4 (w/w), f1:9 (w/w). Arrows indicate quinacridone particles.

Osmium coating enables high-resolution imaging of samples without inducing any structural damage, even at 100,000x. This technique is particularly beneficial for heat-sensitive and fine-structured samples, as it eliminates the granular appearance and electron beam damage commonly associated with other coating methods.

Data provided by Tohoku University, Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Yoshiro Shibata

Clear, high-resolution images of rough-surfaced samples, such as coal ash in cement, can be obtained with osmium coating, eliminating charging artifacts even at 150,000x.

Osmium coating enables high-quality, three-dimensional imaging of samples, even under low-vacuum conditions, without charging artifacts. While uncoated samples are difficult to observe beyond 2000x due to charging under low vacuum conditions, osmium coating enables clear observation of filter structures even at 5000x.

Even challenging samples including filters that are difficult to image under low vacuum conditions can be clearly visualized by switching to high vacuum mode after osmium coating.

The image below shows that the structure is complex and intricate, designed to capture fine particles.

The three-dimensional structure of the surface, including pores as small as a few micrometers in diameter, can be clearly observed.

Sepharose, a type of polymer bead commonly used for adsorption of biological samples such as proteins and microorganisms, has a porous surface.

Osmium coating can coat the deep pores, enabling clear observation of complex structures even at high magnification without granular artifacts.

Even porous samples can be observed clearly.

Data provided by Tohoku University, Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Yoshiro Shibata

Star sand, primarily composed of calcium carbonate, has a porous surface. Sputter coating fills the surface irregularities, making it difficult to observe the fine structures at high magnification. The 10,000x image provides a more in-depth view of the pore structure than the 950x image.

Data provided by JEOL Ltd.

The images compare uncoated and osmium-coated green lacewing wings observed under low-acceleration SEM. The uncoated sample exhibits significant electron beam damage, obscuring the delicate, needle-like structures. In contrast, the osmium-coated sample shows minimal damage, allowing for clear observation of the original, fine structures.

The osmium coating is also resistant to heat damage, making it suitable for heat-sensitive materials such as resins and biological samples.

Data provided by Aoyama Gakuin University, College of Science and Engineering, Akito Takashima, Reona Takahashi

Osmium coating allows for detailed observation of the ant’s body surface, revealing fine structures such as the outline and texture of the antennae.

Compared to the uncoated sample, the osmium-coated sample provides a clearer image with sharper edges and more distinct surface features.

Osmium coating is also effective for low-vacuum SEM, and it does not cause heat damage, allowing for clear observation of delicate structures such as the adhesive threads of azalea pollen without damage.

The uncoated azalea leaf exhibits charging artifacts at 800x, while the osmium-coated sample allows for clear observation of stomata at 1300x.

Osmium coating enables the imaging of detailed structures such as surface morphology and the depth of the internal trichomes.

A comparative study of various fibrous materials is conducted using low-magnification SEM.

Significant differences in the microstructure are observed in pulp-based products (Kimwipes, Kimtowels, copy paper) and synthetic fiber products (BEMCOT clean wipes, M-1, wet wipes).

Variations in weave structure are observed between Kimwipes and Kimtowels, and differences in fiber entanglement are shown between BEMCOT clean wipes and M-1, despite being made from the same material. Wet wipes contain fibers with grooves for water absorption, and copy paper shows the presence of calcium and silicon fillers as loading materials. Observation at 5,000x can be easily achieved using only the auto-focus function of a benchtop SEM.

Delicate membrane filters, prone to heat damage, can be effectively imaged using osmium coating without compromising their structural integrity.

The wolf’s fur exhibits no signs of heat damage. The barbed, frayed hairs, susceptible to heat, would typically curl or distort with sputtering.

Most dental implant bodies are made of titanium. The titanium surface of these implant bodies undergoes various treatments such as sandblasting, acid etching, and hydroxyapatite coating in addition to mechanical polishing. These surface treatments increase the contact area between the implant body and the surrounding bone, and at the cellular level, changes in the microstructure and chemical composition of the titanium surface promote adhesion and proliferation of osteoblasts. In this field of research at the Nippon Dental University, osmium coating has been used as a preparation method for SEM observation after surface treatment of titanium.

The following is an SEM image of a titanium surface functionalized with H2O2 hydrothermal oxidation and FGF-2, 24 hours after cell seeding. Cellular adhesion is evident, with no detachment of filopodia.

Data provided by The Nippon Dental University, School of Life Dentistry, Tomonori Matsuno

Under the same observation conditions, beads coated with platinum show significant electron beam damage on the surface. On the other hand, osmium coating provides clear imaging with no damage or charging, even though it is a thin film.

Data provided by Industrial Technology Research Institute (Taiwan)

Serial section SEM method, also known as array tomography, is a technique that enables easy 3D reconstruction by observing continuous ultrathin sections using a scanning electron microscope. In this publication, after fixation and resin embedding, the samples are sectioned using an ultramicrotome, coated with osmium, and observed with a field emission scanning electron microscope. Subsequent 3D reconstruction through image processing enables to analyze fine organelle interactions and reveal the involvement of microlipophagy in pollen maturation in Arabidopsis thaliana.

The osmium coater enables the reproducible formation of highly conductive, ultrathin pure osmium films less than 1 nm thick, ideal for backscattered electron imaging to visualize tissue changes and surface topography. Its non-granular nature allows for the observation of the intrinsic material structure, making it a perfect choice for preparation for serial section SEM.

Image ① Ultrastructural analysis of interactions of vacuoles and lipid bodies by serial section SEM

a–d SEM images of bicellular pollen (a, c) and tricellular pollen (b, d)

e–t Serial section SEM images of the bicellular stage (e–l) and the tricellular stage (m–t)

gc: generative cells, gn: generative nuclei, lb: lipid bodies, sc: sperm cells, sn: sperm nuclei, vac: vacuoles, vc: vegetative cells, vn: vegetative nuclei

Image ② 3D reconstructed images of microlipophagy

a and b are 3D images in the bicellular stage created from Image ① e-l and the tricellular stage created from Image ① m-t, respectively. Magenta structures indicate lipid bodies, and green structures indicate vacuoles

Data provided by Japan Women’s University, Faculty of Science, Department of Chemical and Biological Sciences, Noriko Nagata, Kae Akita

Images:　Figures 4 and 5 in the following link

https://link.springer.com/article/10.1007/s00709-020-01557-2

Original article:　Kae Akita, Tomoko Takagi, Keiko Kobayashi, Kazuyuki Kuchitsu, Tsuneyoshi Kuroiwa & Noriko Nagata (2020) Ultrastructural characterization of microlipophagy induced by the interaction of vacuoles and lipid bodies around generative and sperm cells in Arabidopsis pollen.

Pure osmium’s excellent conductivity and secondary electron emission efficiency prevent charging. This has enabled high-resolution analysis over a wide area of insulating samples, which was previously difficult due to charging caused by electron beam irradiation. The results demonstrate that even an ultrathin osmium coating of 0.25 nm is sufficient to completely shield the sample from the electron beam and provide high-quality backscattered electron data, allowing for detailed analysis of crystal structures such as grain boundaries.

Reference: Transactions of the Japan Society of Mechanical Engineers. Volume 74, No. 739, A

Osaka Institute of Technology, Department of Mechanical Engineering, Yasutomo Uetsuji

Theoretically, the tips of SPM/AFM cantilevers are exposed to extremely high electric fields. Consequently, gold-coated cantilevers frequently experience substantial damage after only a few measurements, rendering them unusable. In contrast, cantilevers coated with osmium exhibit significantly enhanced durability. This allows for the effective reuse of these costly cantilevers.

Data provided by the National Institute of Advanced Industrial Science and Technology (AIST), Tohru Nakamura

Gold sputtering has been the standard for anti-charging in EDS analysis of low atomic number elements like carbon. However, gold films absorb characteristic X-rays, hindering accurate quantitative analysis. Our plasma CVD technology enables the deposition of uniform, ultrathin osmium films, which have minimal X-ray absorption and do not interfere with quantitative analysis. This makes it particularly suitable for the analysis of light elements such as carbon and nitrogen.

Reference: “EDS quantification of light elements using osmium surface coating”
Journal of Mineralogical and Petrological Sciences, Volume 110, page 189-195,2015

Scattered ions during FIB milling can cause damage to the surrounding area. Osmium coating is an effective preparation to protect the damaged area. By eliminating the damage, high-resolution analysis of the outermost surface can be performed at the nanoscale.

SEM observation results: The uncoated sample exhibits severe charging, preventing observation. However, osmium coating provides excellent coverage, eliminating charging even in deep cavities.

Osmium coating enables the analysis of multiple elements and is effective as a sample preparation method for FE-EPMA.

Quantitative analysis of phosphorus is successfully performed.

Good observation results are obtained even for samples with uneven surfaces.

Energy dispersive X-ray spectroscopy (EDS) analysis is performed on a glass slide coated with an osmium film less than 1 nm thick. While gold and platinum elements are detected, respectively, osmium is not detected in the EDS spectrum, indicating that it does not interfere with the analysis.

An osmium metal film is used as a protective coating prior to FIB processing. The high conductivity and thermal dissipation of the osmium film effectively shields the sample surface from FIB damage. Moreover, the osmium film can be easily removed using hypochlorous acid, allowing for further analysis of the sample after FIB processing.