Calcite Nanotuned Chitinous Skeletons of Giant Ianthella basta Marine Demosponge

Abstract

Marine sponges were among the first multicellular organisms on our planet and have survived to this day thanks to their unique mechanisms of chemical defense and the specific design of their skeletons, which have been optimized over millions of years of evolution to effectively inhabit the aquatic environment. In this work, we carried out studies to elucidate the nature and nanostructural organization of three-dimensional skeletal microfibers of the giant marine demosponge Ianthella basta, the body of which is a micro-reticular, durable structure that determines the ideal filtration function of this organism. For the first time, using the battery of analytical tools including three-dimensional micro—X-ray Fluorescence (3D-µXRF), X-ray diffraction (XRD), infra-red (FTIR), Raman and Near Edge X-ray Fine Structure (NEXAFS) spectroscopy, we have shown that biomineral calcite is responsible for nano-tuning the skeletal fibers of this sponge species. This is the first report on the presence of a calcitic mineral phase in representatives of verongiid sponges which belong to the class Demospongiae. Our experimental data suggest a possible role for structural amino polysaccharide chitin as a template for calcification. Our study suggests further experiments to elucidate both the origin of calcium carbonate inside the skeleton of this sponge and the mechanisms of biomineralization in the surface layers of chitin microfibers saturated with bromotyrosines, which have effective antimicrobial properties and are responsible for the chemical defense of this organism. The discovery of the calcified phase in the chitinous template of I. basta skeleton is expected to broaden the knowledge in biomineralization science where the calcium carbonate is regarded as a valuable material for applications in biomedicine, environmental science, and even in civil engineering.

Calcium carbonate: controlled synthesis, surface functionalization, and nanostructured materials

“…1,2 In addition, CaCO 3 is present in many living organisms, functioning either as a structural support ( e.g. , in algae, 3 sponges, 4,5 corals 6 ), a form of protection ( e.g. , shells), 7 a hard buoyancy tank ( e.g.…”

Identification of Chitin Allomorphs in Poorly Crystalline Samples Based on the Complexation with Ethylenediamine

“…Chitin is one of the principal organic skeletal components in invertebrate animals such as arthropods, mollusks, sponges, cnidarians, and annelids. − Chitin is bio-synthesized in the form of microfibrils, where the elongated chitin molecules are packed in a highly ordered manner to form nanofibrous structures. − Chitin crystalline nanofibers exhibit two distinctive forms, one with an antiparallel packing of chitin molecules known as α-chitin, , and another with a parallel packing known as β-chitin, − both of which occur in nature and are biosynthesized by organisms. , In addition, γ-chitin has been described as a third allomorph, but it is structurally close to α-chitin and generally considered to be a variant of α-chitin. , Arthropods such as crustaceans produce α-chitin, which is thought to be more abundant naturally compared to β-chitin, which is the main allomorph produced by diatoms, , annelid worms, and mollusks such as squids . The two forms in chitin are analogous to cellulose, which also forms parallel (cellulose I) and anti-parallel (cellulose II) packing, but in cellulose, only the parallel-packed cellulose I occurs naturally .…”

Metal acetylacetonates dissolved in UV-curing resin as solid reference material for trace element measurements in organic samples

“…The stackability of UV-curing resins opens up totally new fields of applications for reference-based investigations of layered materials like automotive coatings, archaeometry of paintings and of depth distributed elements in carbon-based matrices. 11,27,39–43 Hereby, CμXRF provides a completely non-destructive and three-dimensional resolved elemental analysis method. 27,29…”

“…The stackability of UV-curing resins opens up totally new elds of applications for reference-based investigations of layered materials like automotive coatings, archaeometry of paintings and of depth distributed elements in carbon-based matrices. 11,27,[39][40][41][42][43] Hereby, CmXRF provides a completely nondestructive and three-dimensional resolved elemental analysis method. 27,29 In order to verify the prepared multi-layers d-I, d-II and d-III as stratied in-house reference materials for CmXRF analysis, the layer sequences and the depth-dependent homogeneity of the Fe distribution within the individual layers were examined.…”