Faraday Discussions最新文献_第3页

Detection limits of calcium by EELS, TEM-EDX and X-ray absorption spectroscopy for biomineralization studies. 生物矿化研究中EELS、TEM-EDX和x射线吸收光谱对钙的检出限。

IF 3.3 3区化学

Faraday Discussions Pub Date : 2025-05-30 DOI: 10.1039/d5fd00001g

Peter Rez, Lothar Houben, Yu-Feng Meng, Assaf Gal, Zdravko Kochovski, Benedikt Haas

{"title":"Detection limits of calcium by EELS, TEM-EDX and X-ray absorption spectroscopy for biomineralization studies.","authors":"Peter Rez, Lothar Houben, Yu-Feng Meng, Assaf Gal, Zdravko Kochovski, Benedikt Haas","doi":"10.1039/d5fd00001g","DOIUrl":"https://doi.org/10.1039/d5fd00001g","url":null,"abstract":"To investigate the mechanisms of biomineral formation it is necessary to determine Ca concentrations in the vicinity of growing minerals at the highest spatial resolution. All techniques that use ionizing radiation will be limited by the onset of radiation damage. Limits to the minimum concentrations of Ca and minimum number of Ca atoms that can be detected are determined for EELS in TEM using the Ca L23 signal, and EDX in TEM using the Ca Kα line. A similar approach is used to set limits on what can be achieved via soft X-ray absorption spectroscopy detecting the Ca L23 features. Due to the large background, the lowest concentrations that can be detected via EELS are about 1 mM. Although the collection efficiency for EDX is inferior to that of EELS, the much lower background signal means that concentrations of about 0.05 mM could be detected, 20 times better than EELS. The spatial resolution of soft X-ray absorption spectroscopy is much lower, about 20 nm, but since the Ca L23 lines are at lower energies than the oxygen K edge that dominates the spectrum, the detection limits for Ca in an aqueous environment can be as low as 35 nM.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144179558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Biomineral displays systematic spatially varying crystallographic properties in fibrolamellar bone as revealed by position resolved X-ray diffraction. 位置分辨x射线衍射显示，生物矿物在纤维板层骨中显示出系统的空间变化的晶体学性质。

IF 3.3 3区化学

Faraday Discussions Pub Date : 2025-05-30 DOI: 10.1039/d5fd00030k

Adrian Rodriguez-Palomo, Peter Alling Strange Vibe, Mads Ry Vogel Jørgensen, Henrik Birkedal

引用次数: 0

Synchrotron X-ray nanoprobe and correlative electron microscopy reveal the role of surface chemistry of self-assembling peptides in calcium phosphate nucleation. 同步x射线纳米探针和相关电子显微镜揭示了自组装肽在磷酸钙成核中的表面化学作用。

IF 3.3 3区化学

Faraday Discussions Pub Date : 2025-05-30 DOI: 10.1039/d5fd00017c

Reham Gonnah, Julia E Parker, Robert P W Davies, Maisoon Al-Jawad

{"title":"Synchrotron X-ray nanoprobe and correlative electron microscopy reveal the role of surface chemistry of self-assembling peptides in calcium phosphate nucleation.","authors":"Reham Gonnah, Julia E Parker, Robert P W Davies, Maisoon Al-Jawad","doi":"10.1039/d5fd00017c","DOIUrl":"https://doi.org/10.1039/d5fd00017c","url":null,"abstract":"A biomimetic peptide (P11-4), which is predominantly negatively-charged, facilitates the nucleation of hydroxyapatite (HAp). P11-4 self-assembles into fibrils via β-sheet formation, creating a 3D-gel-network. Here, X-ray nanoimaging and correlative scanning electron microscopy (SEM) investigated P11-4's surface chemistry and its ability to nucleate HAp in the absence of the 3D-gel-network. P11-4 was deposited on silicon nitride (SiN) windows, which were immersed in a mineralising solution (MS) and then mapped using nano-X-ray fluorescence (n-XRF) and differential phase contrast imaging at the hard X-ray nanoprobe beamline (I14) at Diamond Light Source. Elemental calcium and phosphorus maps were extracted using n-XRF, and compared with and without P11-4. The windows were subsequently mapped using SEM and Energy Dispersive Spectroscopy (EDS) to confirm the morphology and elemental compositions of the formed structures. The calcium : phosphorus ratios were calculated to identify the phases formed. P11-4 increased the calcium and phosphorus signals with time in MS compared to the control (without P11-4). After 12 hours in MS, calcium ions accumulated on the deposited β-sheets, attracting phosphorus ions at later time points. From the morphology in the images and EDS analysis, the spherical calcium phosphate (CaP) structures appeared to be amorphous, indicating the formation of precursors, likely amorphous CaP, at early time points. In the presence of P11-4, these structures grew and fused into larger CaP formations over time, unlike in the control. Nano-imaging techniques highlighted that P11-4's surface chemistry accelerates the kinetics and controls the initial CaP crystallisation process, resulting in an amorphous CaP phase.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144179784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Designing anti-bacterial supramolecular gels from primary ammonium dicarboxylate (PAD) salts for self-delivery applications. 从二羧酸原铵（PAD）盐中设计抗菌超分子凝胶用于自我递送应用。

IF 3.3 3区化学

Faraday Discussions Pub Date : 2025-05-29 DOI: 10.1039/d4fd00154k

Nabanita Roy, Subhajit Ghosh, Abhishek Dutta, Parthasarathi Dastidar

{"title":"Designing anti-bacterial supramolecular gels from primary ammonium dicarboxylate (PAD) salts for self-delivery applications.","authors":"Nabanita Roy, Subhajit Ghosh, Abhishek Dutta, Parthasarathi Dastidar","doi":"10.1039/d4fd00154k","DOIUrl":"https://doi.org/10.1039/d4fd00154k","url":null,"abstract":"Primary ammonium dicarboxylate (PAD) salts often display 2D columnar hydrogen bonded networks known as the PAD supramolecular synthon in the context of crystal engineering. The PAD synthon is known to play an effective role in supramolecular gelation. Vehicle-free drug delivery (VFDD) vis-à-vis conventional drug delivery (CDD), is advantageous as it does not require any vehicle to deliver the drug. In here, we disclose the development of an anti-bacterial VFDD system based on PAD salts. Synthesis, structure and supramolecular gelation behaviour of 20 PAD salts derived from 5 dicarboxylic acids - (CH2)n-(COOH)2 (n = 4, 7, 10, 12 and 14) - and 4 therapeutic amines - amantadine (AMN), tyramine (TRM), tryptamine (TRP) and mafenide (MAF) - are reported. Interestingly, 40% of the PAD salts were able to gel methyl salicylate (MS) - an important ingredient in many commercially available topical ointments. The gels were characterized by rheology and TEM. The underlying supramolecular interactions were analysed using single crystal X-ray diffraction (SXRD) studies carried out on as many as 9 salts. The gelator salt, C14·2MAF, containing anti-bacterial drug MAF as the amine part, showed excellent anti-bacterial behaviour against E. coli. Detailed biological studies suggested that the C14·2MAF anti-bacterial property is caused by bacterial cell membrane disruption and ROS generation. Gradual release of C14·2MAF from a MS-gel bed and sheer thinning of the gel phase, clearly indicated that the C14·2MAF MS gel has potential use as a supramolecular topical gel for anti-bacterial treatment.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144172065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Silica biomineralization in plants alters the structure of lignin. 植物中二氧化硅生物矿化改变了木质素的结构。

IF 3.3 3区化学

Faraday Discussions Pub Date : 2025-05-29 DOI: 10.1039/d5fd00011d

Srinath Palakurthy, Michael Elbaum, Rivka Elbaum

{"title":"Silica biomineralization in plants alters the structure of lignin.","authors":"Srinath Palakurthy, Michael Elbaum, Rivka Elbaum","doi":"10.1039/d5fd00011d","DOIUrl":"https://doi.org/10.1039/d5fd00011d","url":null,"abstract":"Biomineralization of silica is a major process in plants, which may contribute 3-10% of tissue dry weight. For reasons that remain unclear, plants containing silica are less sensitive to abiotic and biotic stress. In particular, the mechanisms of silica deposition and stress amelioration are still not fully understood. Silica resides mostly in the extracellular volume (the apoplast) which is made of the lignocellulosic cell wall. In a previous work we showed that synthetic lignin catalyses the formation of silica nanoparticles at RC-OSi(OH)3 positions. Since the phenolic O-4 position is the most reactive during lignin polymerization, the binding sites form at the expense of β-O-4 lignin backbone bonds. Therefore, synthetic lignin becomes more branched when polymerized in the presence of silicic acid, as compared to lignin polymerized without silicic acid. To study lignin-silica relationships in the plant, we extracted lignin from stems of wild type sorghum and compared it to lignin extracted from mutants exhibiting high and low silica contents. The thermal stability of both non-extracted biomass and extracted lignin was measured using thermogravimetric analysis (TGA). High-silica biomass was thermally less stable than low-silica biomass, suggesting lower content of ether (β-O-4) linkages. This interpretation was supported by gas chromatography-mass spectroscopy (GC-MS). Fourier transform infrared (FTIR) and X-ray photoelectron spectra (XPS) indicated lignin with C-O-Si modifications in all genotypes and further showed silicic acid binding to lignin phenolics and carbonyl moieties. Our results show that lignin extracted from genotypes with native-silicon levels have higher affinity to silicic acid, catalysing silica deposition through Si-O-4 (Si-phenoxyl) bonds, and suggest that the presence of silicic acid during in vivo lignin polymerization reduces β-O-4 ether linkages.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144172067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Bone mineralization and the effects of elevated osteopontin: from symmetry-breaking foci to 3D space-filling tessellation. 骨矿化和骨桥蛋白升高的影响：从对称性破坏病灶到三维空间填充镶嵌。

IF 3.3 3区化学

Faraday Discussions Pub Date : 2025-05-29 DOI: 10.1039/d5fd00013k

Joseph Deering, Daniel J Buss, Roland Kröger, Hojatollah Vali, Maureen J Lagos, Natalie Reznikov, Marc D McKee

{"title":"Bone mineralization and the effects of elevated osteopontin: from symmetry-breaking foci to 3D space-filling tessellation.","authors":"Joseph Deering, Daniel J Buss, Roland Kröger, Hojatollah Vali, Maureen J Lagos, Natalie Reznikov, Marc D McKee","doi":"10.1039/d5fd00013k","DOIUrl":"10.1039/d5fd00013k","url":null,"abstract":"At the nanoscale, lamellar bone tissue mineralization ensues via heteronucleation of small mineral foci within the osteoid. The foci grow to produce a mature, volume-filling tessellation pattern at the micrometer-scale. Mineralization-inhibiting osteopontin (OPN) mediates this bone mineralization pathway and, eventually, the microscale properties of bone tissue. Using 2D and 3D electron microscopy, here we have assessed how the abundance of OPN can affect nanoscale mineralization, mineral ripening, and microscale patterning of mineral in normal wild-type mouse bone, and we compare that to mutant mouse models having elevated OPN (Fgf23-/- and Hyp mice). When OPN is elevated, volume-filling mineral tessellation was incomplete (showing a four-fold increase in mineral surface area in the vicinity of the mineralization front in Hyp bone). Immunogold labeling showed excessive OPN in the foci, suggesting an arrest of their growth and an interruption of the pathway towards microscale tessellation. In Fgf23-/- mice, electron tomography and 3D focused ion beam-scanning electron microscopy (FIB-SEM) imaging of mineral foci show instances of core-shell morphology with crystalline mineral confined to the focus interior, and an amorphous nanogranular texture persisting in the outer shell. Electron energy-loss spectroscopy, which is sensitive to nanoscale elemental composition, showed a lower Ca/P ratio at the periphery of Hyp foci, consistent with a more amorphous mineral character, suggesting that OPN may play a role in delaying the amorphous-to-crystalline transition. These aspects of nanoscale mineral maturation in mutant mice having elevated OPN implicate this protein as a fine-tuning regulator of mineralization kinetics, mineral composition, and mechanical properties of bone.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12123585/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144172063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Investigating temperature influences on shell growth and microstructural variations in bay scallops: insights from multiscale microscopy. 研究温度对海湾扇贝壳生长和微观结构变化的影响：来自多尺度显微镜的见解。

IF 3.3 3区化学

Faraday Discussions Pub Date : 2025-05-27 DOI: 10.1039/d5fd00023h

Benazir Khurshid, Arnaud Benchetrite, Lise Guichaoua, Nicolas Brodusch, Bryce D Stewart, Roland Kröger, Raynald Gauvin, Martin Mallet, Réjean Tremblay, Natalie Reznikov

{"title":"Investigating temperature influences on shell growth and microstructural variations in bay scallops: insights from multiscale microscopy.","authors":"Benazir Khurshid, Arnaud Benchetrite, Lise Guichaoua, Nicolas Brodusch, Bryce D Stewart, Roland Kröger, Raynald Gauvin, Martin Mallet, Réjean Tremblay, Natalie Reznikov","doi":"10.1039/d5fd00023h","DOIUrl":"https://doi.org/10.1039/d5fd00023h","url":null,"abstract":"Scallops (order Pectinida) are well-known for their robust and beautiful calcitic shells that protect them from external impacts and predators. Scallops respond to environmental conditions, including water temperature, salinity, and food supply, which are reflected in the shell growth rates and patterning. The bay scallop (Argopecten irradians) is a species of high ecological and aquacultural value in North America, and its habitat may expand towards higher latitudes with inevitable global warming. To investigate the effect of water temperature on the accretion rate and the polycrystalline microstructure of the Bay scallop shell, we conducted a controlled growth experiment on juveniles, 4 weeks following their larval metamorphosis. Approximately 400 individuals, collected from a hatchery 4 weeks after metamorphosis, were then reared in reconstituted seawater for 9 weeks at 23 °C and 26 °C. At 7-, 9-, 11-, and 13-weeks post-metamorphosis, calcein was added to the water for 7 hours for fluorescent staining, and then equal batches of scallops were collected and fixed. Morphologic characterization of bay scallop shells included micro-computed X-ray tomography for 3D measurements to measure shell thickness, and fluorescence light microscopy for accretion rate assessment. We used mechanical testing of complete shells in compression to assess their stiffness, strength and toughness. Microstructural analysis of the shells included scanning electron microscopy and crystallographic analysis by electron backscattered diffraction. The scallops reared in warmer water exhibited a faster growth rate with shells showing higher calcite grain misorientation, no difference in relative shell thickness, and inconclusive difference in the shell mechanical properties. This study may help us to understand the multifarious implications of climate change.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144148705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Three-dimensional imaging of vasculature and forming quail femur using cryo-correlative light and electron microscopy (cryo-CLEM). 用低温相关光电子显微镜（cryo-CLEM）观察鹌鹑股骨血管和成形的三维成像。

IF 3.3 3区化学

Faraday Discussions Pub Date : 2025-05-27 DOI: 10.1039/d5fd00022j

Anne Seewald, Jingxiao Zhong, Macarena Siri, Peter Fratzl, Emeline Raguin

{"title":"Three-dimensional imaging of vasculature and forming quail femur using cryo-correlative light and electron microscopy (cryo-CLEM).","authors":"Anne Seewald, Jingxiao Zhong, Macarena Siri, Peter Fratzl, Emeline Raguin","doi":"10.1039/d5fd00022j","DOIUrl":"https://doi.org/10.1039/d5fd00022j","url":null,"abstract":"Bone mineralization during embryonic development requires the transport and deposition of an enormous amount of mineral precursors. In avian embryos, blood vessels play a dual role in this context: facilitating the demineralization of the eggshell to supply calcium and other minerals on the one hand, and mediating their deposition into the developing skeleton on the other. Understanding the interface between blood vessels and the surrounding tissues is therefore crucial for unraveling the mechanisms underlying biomineralization. However, visualizing this interface poses significant challenges and requires imaging methods that preserve the ultrastructure in a close-to-native state. Here we present a detailed methodology for a cryogenic correlative light and electron microscopy (cryo-CLEM) workflow to investigate the transport of mineral precursors in blood vessels of the femur of quail embryos during bone development. To achieve this, we use a fluorophore-conjugated antibody to label endothelial cells, which form the inner lining of blood vessels and which mediate exchanges between the bloodstream and developing tissues. This approach enables precise localization of blood vessels through fluorescence microscopy, which is subsequently correlated with 3D high-resolution electron microscopy using Focused Ion Beam-Scanning Electron Microscopy (FIB-SEM). This methodology allows imaging of a sufficient volume to observe both the lumen of the blood vessels and the surrounding matrix, providing deeper insights into calcium transport and bone mineralization during quail embryogenesis.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144148707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Fiber formation seen through the high-resolution computational microscope. 通过高分辨率计算机显微镜观察到的纤维形成。

IF 3.3 3区化学

Faraday Discussions Pub Date : 2025-05-23 DOI: 10.1039/d4fd00188e

Tomasz K Piskorz, Vasudevan Lakshminarayanan, Alex H de Vries, Jan H van Esch

{"title":"Fiber formation seen through the high-resolution computational microscope.","authors":"Tomasz K Piskorz, Vasudevan Lakshminarayanan, Alex H de Vries, Jan H van Esch","doi":"10.1039/d4fd00188e","DOIUrl":"https://doi.org/10.1039/d4fd00188e","url":null,"abstract":"Supramolecular fibers draw widespread attention due to their role in biological systems and ability to form complex materials exhibiting rich and dynamic behavior. Although the information about the supramolecular structure is encoded in their molecular blocks, a complete understanding of how this information translates into the final structure requires detailed insights into the energy landscape of the process and the possible routes across this landscape. Here, we study the formation of 1,3,5-cyclohexanetricarboxamide fibers by a Markov state model of molecular dynamics simulations with the polarizable CHARMM Drude force-field. We provide insights into all stages of supramolecular fiber formation up to microsecond timescales, starting from primary nucleation, through fiber elongation and secondary nucleation, and finally, the assembly of single fibers into bundles. Our results show that nucleation involves a rapid collapse of dissolved monomers into disordered assemblies, which gradually transform into nuclei and then grow into elongated fibers. Moreover, elongation and secondary nucleation appeared to be competing processes, depending on the density of the monomers adsorbed at the fiber-liquid interface. Finally, bundling involves the initial association of fibers by interactions between surface-exposed groups, followed by stabilization of the bundle by surface reorganization, which allows for favorable interactions between aromatic groups.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144126252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Revealing enameloid shark chemistry at the nanoscale. 在纳米尺度上揭示类搪瓷鲨鱼的化学性质。

IF 3.3 3区化学

Faraday Discussions Pub Date : 2025-05-23 DOI: 10.1039/d5fd00019j

Alberto Perez-Huerta, Eshita Samajpati, Gabriela A Farfan

{"title":"Revealing enameloid shark chemistry at the nanoscale.","authors":"Alberto Perez-Huerta, Eshita Samajpati, Gabriela A Farfan","doi":"10.1039/d5fd00019j","DOIUrl":"https://doi.org/10.1039/d5fd00019j","url":null,"abstract":"Shark teeth are considered excellent bio-archives because of their high abundance and preservation potential. Chemical proxies recorded by the teeth enameloid layers are used to interpret ecological and environmental parameters throughout the geological record. The use of these proxies relies on the assumption that biomineralization processes for enameloid formation have remained constant during shark evolution. Here, we test such an assumption by comparing the chemical composition at the nanoscale, using the technique of atom probe tomography (APT), of enameloid in modern and fossil shark teeth. Results indicate that there are clear differences in the chemistry at the core and inter-crystalline grain boundaries of fluorapatite crystals. These boundaries are enriched in strontium in all shark teeth, whereas there are differences in the distribution of magnesium, sodium, and iron. Teeth of the modern shark Isurus oxyrinchus have magnesium and sodium distributed at the inter-crystalline grain boundaries. Teeth of Eocene fossil sharks, Striatolamia macrota and Macrorhizodus praecursor, have a unique distribution of iron, at the inter-crystalline boundaries, and sodium, at the core of the crystals. This observation may indicate that biomineralization processes resulting in enameloid formation are not constant across the phylogeny of sharks. Overall, our findings strongly suggest that the enameloid content and distribution of magnesium, iron, strontium, and sodium are highly controlled by biomineralization processes. The role of magnesium and sodium seems to be similar in mammalian enamel and shark enameloid formation. Yet, nanoscale chemical differences, such as the presence of strontium in tooth enameloid, are likely associated to functional morphology.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144126253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0