Visualization of the internal structure of Didymosphenia geminata frustules using nano X-ray tomography

Abstract

For the first time, the three-dimensional (3D) internal structure of naturally produced Didymosphenia geminata frustules were nondestructively visualized at sub-100 nm resolution. The well-optimized hierarchical structures of these natural organisms provide insight that is needed to design novel, environmentally friendly functional materials. Diatoms, which are widely distributed in freshwater, seawater and wet soils, are well known for their intricate, siliceous cell walls called ‘frustules’. Each type of diatom has a specific morphology with various pores, ribs, minute spines, marginal ridges and elevations. In this paper, the visualization is performed using nondestructive nano X-ray computed tomography (nano-XCT). Arbitrary cross-sections through the frustules, which can be extracted from the nano-XCT 3D data set for each direction, are validated via the destructive focused ion beam (FIB) cross-sectioning of regions of interest (ROIs) and subsequent observation by scanning electron microscopy (SEM). These 3D data are essential for understanding the functionality and potential applications of diatom cells.

Diatom Frustule‐Inspired Metamaterial Absorbers: The Effect of Hierarchical Pattern Arrays

“…It is well known that diatom frustules, regardless of the species, have hierarchical pore structures . The hierarchical pore structures of the Coscinodiscus species ( C .…”

Anisotropy of Mechanical Properties of Pinctada margaritifera Mollusk Shell

“…For these studies, a laboratory transmission X-ray microscope Xradia Nano-XCT-100 (Concord, California) operated at a photon energy of 8.0 keV (Cu-Kα radiation) [20][21][22] was used during the micro-indentation test to visualize the crack propagation. A detailed experimental setup was described elsewhere by Zgłobicka et al [23]. For these experiments, small rectangular specimens with a cross-section of approximately 50 μm × 50 μm and a length of 200 μm were prepared using diamond disc sawing and subsequent polishing.…”

3D Diatom–Designed and Selective Laser Melting (SLM) Manufactured Metallic Structures

“…A nano-XCT tool (Xradia 100, Xradia Inc., Concord/CA, USA) operated with Cu-Kα radiation was used to image the frustule of D. geminata 24,29 . This tool provides the resolution needed, i.e.…”

“…Such two-dimensional (2D) visualization of biological objects is a routine task. Commonly, focused ion beam (FIB) serial cutting and subsequent scanning electron microscopy (SEM) imaging is the approach of choice for preparing and examining specimens at target sites 24 . The three-dimensional (3D) object is reconstructed from a large number of 2D images.…”

“…In contrast to the destructive serial cutting technique, nano X–ray computed tomography (nano-XCT) provides detailed 3D information of the morphology of diatom frustules with sub-100 nm resolution 24 . Large field-of-view imaging provides an overview of the sample and allows the identification of a region of interest (ROI), and subsequent small field-of-view imaging enables the visualization of the ROI with higher resolution.…”