Modifying the thickness, pore size, and composition of diatom frustule in Craspedostauros sp. with Al3+ ions

Abstract

Diatoms are unicellular photosynthetic algae that produce a silica exoskeleton (frustule) which exposes a highly ordered nano to micro scale morphology. In recent years there has been a growing interest in modifying diatom frustules for technological applications. This is achieved by adding non-essential metals to the growth medium of diatoms which in turn modifies morphology, composition, and resulting properties of the frustule. Here, we investigate the frustule formation in diatom Pinnularia sp., including changes to overall morphology, silica thickness, and composition, in the presence of Al3+ ions at different concentrations. Our results show that in the presence of Al3+ the total silica uptake from the growth medium increases, although a decrease in the growth rate is observed. This leads to a higher inorganic content per diatom resulting in a decreased pore diameter and a thicker frustule as evidenced by electron microscopy. Furthermore, 27Al solid-state NMR, FIB-SEM, and EDS results confirm that Al3+ becomes incorporated into the frustule during the silicification process, thus, improving hydrolysis resistance. This approach may be extended to a broad range of elements and diatom species towards the scalable production of silica materials with tunable hierarchical morphology and chemical composition.

Multiscale characterization of pathological bone tissue

“…Therefore, SEM by employing FIB‐SSV and TEM by employing ET can be used profitably in the elucidation of the ultrastructure of healthy and pathological bone. Last but not least, techniques involving electron microscopes not only provide structural information of the bone tissue, but can also provide useful structural insights into other biological or synthetic materials such as biological exoskeletons (Rivera et al, 2020 ; Soleimani et al, 2020 ; Sun & Bhushan, 2012 ; Yao et al, 2010 ), biomimetic materials (Dede Eren et al, 2020 ; Mohammadi, Sesilja Aranko, Paul Landowski, Wagermaier, & Linder, 2019 ; Wegst, Bai, Saiz, Tomsia, & Ritchie, 2015 ), and implant materials (Linder et al, 1983 ; Mendonça, Mendonça, Aragão, & Cooper, 2008 ; Thorfve, Palmquist, & Grandfield, 2015 ).…”

Diatom microalgae as smart nanocontainers for biosensing wastewater pollutants: recent trends and innovations

“…There are about 20,000 species of diatoms with pores arranged in a beautiful and rigid walled nanoarchitecture [ 52–54 ]. These pores range in size from 3 to 50 nm in diameter [ 55 ]. Besides being found in all types of water bodies they are photosynthetic, convert atmospheric CO 2 to carbohydrates, thus forming different biomolecules like proteins, lipids, carotenoids, etc.…”

Multi-Element Composition of Diatom Chaetoceros spp. from Natural Phytoplankton Assemblages of the Russian Arctic Seas

“…At the same time, the role of this element in biomineralization has not been fully studied, nor has its effect on the structure of the formed BSi. Several studies reported that Al has been uptaken by the cell when forming the frustule [88]. Aluminum is included into the frustule during silicification, which suggests the structural incorporation of Al inside the silica framework synthesized by the organism.…”

“…The incorporation of Al into the diatom frustule modifies its properties and affects the solubility of BSi [89,90]. Most notably, Al incorporation into the frustules of several diatom species leads to a significantly enhanced hydrolysis resistance and longer lifetime of frustules compared to Al-free ones [88,90,91].…”