X-ray Tomographic Microscopy Research Articles

Humidity-responsive actuators of synthesized graphene oxide/gelatin composite hydrogels: Effect of oxidation degree of graphene oxide

In this study, graphene oxide (GO) was prepared for humidity-responsive actuator application. GO has outstanding properties such as single-atom thickness, abundant oxygen, water solubility, and good moisture absorption. GO was prepared at various graphite:potassium permanganate (oxidizer) ratios (1:1, 1:2, 1:3, and 1:4; the corresponding structures are denoted as GO1, GO2, GO3, and GO4, respectively). The GO particles synthesized according to the effect of the oxidizer ratio were characterized to elucidate the internal morphology and humidity response. The defects and disorders and morphological properties of the GO particles were characterized by Raman spectroscopy and transmission electron microscopy (TEM), respectively. To study the humidity-responsive properties, the prepared GO was blended with gelatin (GEL). The bending angle of the GO/GEL hydrogel was studied at relative humidities of 80–85 % at 37 ºC. The internal structure morphology of the blend gel was analyzed by synchrotron radiation X-ray tomographic microscopy. GO2/GEL was selected for the development of a humidity-responsive actuator because of its optimal intensity ratio (ID/IG) in the Raman spectrum. X-ray and TEM images showed the good dispersion of GO2 particles in the hydrogel matrix. GO2/GEL exhibited the largest bending angle (θ = 930.11 ± 49.28º) and fast humidity response (angular rate of change ∼ 9.380 ± 0.513 ºs−1). Thus, GO2 particles are suitable for use as a humidity-responsive material for humidity actuator applications.

Increased cancellous bone mass accompanies decreased cortical bone mineral density and higher axial deformation in femurs of leptin-deficient obese mice

IntroductionLeptin is a pleiotropic hormone that regulates food intake and energy homeostasis with enigmatic effects on bone development. It is unclear if leptin promotes or inhibits bone growth. The aim of this study was to characterize the micro-architecture and mechanical competence of femur bones of leptin-deficient mice. Materials and methodsRight femur bones of 15-week old C57BL/6 (n = 9) and leptin-deficient (ob/ob, n = 9) mice were analyzed. Whole bones were scanned using micro-CT and morphometric parameters of the cortex and trabeculae were assessed. Elastic moduli were determined from microindentations in midshaft cross-sections. Mineral densities were determined using quantitative backscatter scanning electron microscopy. 3D models of the distal femur metaphysis, cleared from trabecular bone, were meshed and used for finite element simulations of axial loading to identify straining differences between ob/ob and C57BL/6 controls. ResultsCompared with C57BL/6 controls, ob/ob mice had significantly shorter bones. ob/ob mice showed significantly increased cancellous bone volume and trabecular thickness. qBEI quantified a ∼7% lower mineral density in ob/ob mice in the distal femur metaphysis. Indentation demonstrated a significantly reduced Young's modulus of 12.14 [9.67, 16.56 IQR] GPa for ob/ob mice compared to 23.12 [20.70, 26.57 IQR] GPa in C57BL/6 mice. FEA revealed greater deformation of cortical bone in ob/ob as compared to C57BL/6 mice. ConclusionLeptin deficient ob/ob mice have a softer cortical bone in the distal femur metaphysis but an excessive amount of cancellous bone, possibly as a response to increased deformation of the bones during axial loading. Both FEA and direct X-ray and electron microscopy imaging suggest that the morphology and micro-architecture of ob/ob mice have inferior biomechanical properties suggestive of a reduced mechanical competence.

Characterization of human trabecular bone across multiple length scales using a correlative approach combining X-ray tomography with LaserFIB and plasma FIB-SEM

Three-dimensional correlative multimodal and multiscale imaging is an emerging method for investigating the complex hierarchical structure of biological materials such as bone. This approach synthesizes images acquired across multiple length scales, for the same region of interest, to provide a comprehensive view of the material structure of a sample. Here, we develop a workflow for the structural analysis of human trabecular bone using a femtosecond laser to produce a precise grid to facilitate correlation between imaging modalities and identification of structures of interest, in this case, a single trabecula within a volume of trabecular bone. Through such image registration, high resolution X-ray microscopy imaging revealed fine architectural details, including the cement sheath and bone cell lacunae of the selected bone trabecula. The selected bone volume was exposed with a combination of manual polishing and site-specific femtosecond laser ablation and then examined with plasma focused ion beam-scanning electron microscopy. This reliable and versatile correlation approach has the potential to be applied to a variety of biological tissues and traditional engineered materials. The proposed workflow has the enhanced capability for generating highly resolved and broadly contextualized structural data for a better understanding of the architectural features of a material spanning its macroscopic to nanoscopic levels.

Virtual histology based on 3D X-ray microscopy imaging for non-destructive age-at-death estimation of incinerated teeth from the Tophet of Motya (Sicily, 6th century BC)

The reconstruction of infant biological history and mortality profiles provides biocultural insights into adulthood morbidity, maternal health, parental caregiving practices, and social dynamics. However, interpreting biological data from cremated infant remains in archaeological contexts can be challenging due to their often poor preservation and potential biases. Tophets, sanctuaries for distinct burial of cremated infant remains present in several Phoenician-Punic colonies in the Mediterranean area, offer an ideal case study. This study presents the first virtual histology performed in X-ray Microscopy-based imaging (XRM) on a sample of crowns of cremated deciduous teeth from the Tophet of Motya (Sicily, 6th century BC). The observation of the Neonatal Line (NL) in enamel tissue offers important informations on the community demographic profile, age-at-death classes and life-histories of the buried individuals. Results are consistent with previous studies on other human remains found in the main Tophets in Mediterranean basin and highlight the importance of using non-invasive techniques to collect and analyse data that are useful for the interpretation of newborns and infants burial practices.

Probing microstructure evolution of Si/C anode for Li-ion batteries via synchrotron transmission X-ray tomographic microscopy

Holding great potentials as an excellent anode for Li-ion batteries, Si has received enormous attention, and its degradation theory has been enriched extensively based on various characterizations over time. To provide a more comprehensive diagnosis for current Si/C anodes, ex situ phase-contrast synchrotron transmission X-ray tomographic microscopy (TXTM) is applied to study a Si/C electrode sampled at representative cycling numbers. Through a series of data segmentations and identifications, three-dimensional Si/C electrodes are described in details with both global and localized structure features, which are rationally linked to the electrochemical characteristics as well as the previous discoveries. This successfully establishes an updated electrode-level failure process for common Si/C anodes where the electrode degradation is primarily initiated by the nonstop Si-phase pulverization with continually-expanded LixSi/electrolyte interface, and manifested as the internal void space expansion and the ever-growing electrode thickness. Bearing this in mind, multiple complementary and synergistic solutions towards limiting the intrinsic Si rupture and electrolyte decomposition should be developed to ensure a high-performance Si-based anode over long-term cycling for Li-ion battery in the near future.

Investigation of Dynamic Water Cluster and Droplet Interactions in Polymer Electrolyte Fuel Cells using Operando X-ray Tomographic Microscopy

Efficient removal of the electrochemically produced water from the gas diffusion layer (GDL) in polymer electrolyte fuel cells is crucial for reducing mass transport losses and improving the efficiency at high current densities. Understanding the relationship between the water percolation through the GDL and droplet formation in the gas channel will allow the design of advanced GDL materials, which provide optimal water management. In this study, a catalyst-coated membrane with 8 individual active areas (0.06 mm2 each) is investigated using operando X-ray tomographic microscopy to study the transient development and interaction of multiple percolating water clusters in a GDL and droplet formation in the channel. The 4D imaging results at a time resolution of 1 Hz showed transient instabilities in the developed percolating water networks at various frequencies associated with break-through and spontaneous water drainage.

Developing long bones respond to surrounding tissues by trans-pairing of periosteal osteoclasts and endocortical osteoblasts.

Developing long bones alter their shape while maintaining uniform cortical thickness via coordinated activity of bone-forming osteoblasts and bone-resorbing osteoclasts at periosteal and endosteal surfaces, a process we designate trans-pairing. Two types of trans-pairing shift cortical bone in opposite orientations: peri-forming trans-pairing (peri-t-p) increases bone marrow space and endo-forming trans-pairing (endo-t-p) decreases it, via paired activity of bone resorption and formation across the cortex. Here, we focused on endo-t-p in growing bones. Analysis of endo-t-p activity in the cortex of mouse fibulae revealed osteoclasts under the periosteum compressed by muscles, and expression of RANKL in periosteal cells of the cambium layer. Furthermore, mature osteoblasts were localized on the endosteum, while preosteoblasts were at the periosteum and within cortical canals. X-ray tomographic microscopy revealed the presence of cortical canals more closely associated with endo- than with peri-t-p. Sciatic nerve transection followed by muscle atrophy and unloading induced circumferential endo-t-p with concomitant spread of cortical canals. Such canals likely supply the endosteum with preosteoblasts from the periosteum under endo-t-p, allowing bone shape to change in response to mechanical stress or nerve injury.

Deep learning-based microstructure analysis of multi-component heterogeneous composites during preparation

Monitoring microstructure evolution during the preparation has always been a difficult problem in the modification studies of SiC composite matrix. Here, we used X-ray tomography microscopy to observe the microstructure of SiCf/SiC-W-ZrB2 composites at different fabrication stage. Based on deep learning, the tracking of the densification process of matrix-modified SiCf/SiC composites was achieved and its suitability for microstructure reconstruction was also verified. The results showed that the average errors of reconstructed SiCf/SiC, pore and Metal (W/ZrB2) are respectively 7.53%, 8.31% and 0.96% by comparison with the segmentation results. Compared with the experimental results, the average error and the average relative error of reconstructed SiCf/SiC is less than 3% and 3.74%.

Indirect detector for ultra-high-speed X-ray micro-imaging with increased sensitivity to near-ultraviolet scintillator emission.

Ultra-high-speed synchrotron-based hard X-ray (i.e. above 10 keV) imaging is gaining a growing interest in a number of scientific domains for tracking non-repeatable dynamic phenomena at spatio-temporal microscales. This work describes an optimized indirect X-ray imaging microscope designed to achieve high performance at micrometre pixel size and megahertz acquisition speed. The entire detector optical arrangement has an improved sensitivity within the near-ultraviolet (NUV) part of the emitted spectrum (i.e. 310-430 nm wavelength). When combined with a single-crystal fast-decay scintillator, such as LYSO:Ce (Lu2-xYxSiO5:Ce), it exploits the potential of the NUV light-emitting scintillators. The indirect arrangement of the detector makes it suitable for high-dose applications that require high-energy illumination. This allows for synchrotron single-bunch hard X-ray imaging to be performed with improved true spatial resolution, as herein exemplified through pulsed wire explosion and superheated near-nozzle gasoline injection experiments at a pixel size of 3.2 µm, acquisition rates up to 1.4 MHz and effective exposure time down to 60 ps.

Utilizing acid-etched Fe-waste for sustainable synthesis of conductive perovskite-type materials from automotive industrial residue

A common method for reducing waste and environmental problems brought on by landfills is to reuse waste, especially heavy metals such as iron. Automotive industrial waste containing Fe-rich metal is successfully transformed into a highly pure structure of Fe2O3 using an etching method with HNO3 acid. This resulting structure serves as a precursor for synthesizing LaNi1-xFexO3±δ perovskite conducting materials. The desired perovskite conductive phase can be produced by substituting Fe2O3-treated waste at the B-site (Ni position) before calcination at 1200 °C. However, LaNiO3±δ and LaNi0.6Fe0.4O3±δ could not be synthesized under ideal conditions, as indicated by XRD analysis using TOPAS software, which revealed the presence of undesirable phases. Both compounds, LaNiO3±δ and LaNi0.6Fe0.4O3±δ demonstrated electrical conductivity with values of 362 S/cm and 42 S/cm at 550 °C, respectively. Nonetheless, electrical conductivity of both compounds decreased due to unintended phase contamination during the synthesis process. The Fe2O3-substituted compounds at the Ni position, in an exact amount of 1 mol, exhibited minimal electrical conductivity. Although the synthesis conditions to produce a single phase of LaFeO3±δ were identified, LaFeO3±δ, despite its low electrical conductivity, is frequently used in electrical devices as a gas detection sensor. The thermal expansion coefficient of all synthesized waste samples is represented in the range of 12–13 × 10−6 °C−1, which is comparable to IT-SOFC electrolyte materials. Furthermore, microstructural investigation revealed that the introduction of Fe into LaNiO3±δ reduced particle size and porosity, ultimately resulting in higher densities. These findings were confirmed through synchrotron radiation x-ray tomographic microscopy (SR-XTM) analysis. The research suggests that converting Fe-waste into a pure phase of Fe2O3 using a strong acid etching technique can serve as a viable precursor for synthesizing conductive materials. This approach enhances the value of industrial waste while also reducing its volume.

Investigation of Stress Corrosion Cracking in CMSX-4 Turbine Blade Alloys Using Deep Learning Assisted X-ray Microscopy and Correlative Imaging Workflow

Investigation of Stress Corrosion Cracking in CMSX-4 Turbine Blade Alloys Using Deep Learning Assisted X-ray Microscopy and Correlative Imaging Workflow

Formation of nanoparticles during accelerated UV degradation of fleece polyester textiles

Micro- and nanoplastics have emerged as critical pollutants in various ecosystems, posing potential environmental and human health risks. Washing of polyester textiles has been identified as one of the sources of nanoplastics. However, other stages of the textile life cycle may also release nanoparticles. This study aimed to examine nanoparticle release during UV degradation of polyester textiles under controlled and real-world conditions. Fleece polyester textiles were weathered under simulated sunlight for up to two months, either in air or submerged in water. We conducted bi-weekly SEM image analyses and quantified released nanoparticles using nanoparticle tracking analysis (NTA). At week 0, the fiber surface appeared smooth after prewashing. In the air group, nanoparticles appeared on the fiber surface after UV-exposure. In the group of textiles submerged in water, the surfaces developed more pits over time. The cumulative nanoparticle emission from the weathered textiles ranged from 1.4 × 1011 to 4.0 × 1011 particles per gram of fabric in the air group and from 1.6 × 1011 to 4.4 × 1011 particles per gram of fabric in the water group over two months. The predominant particle size fell into the 100 to 200 nm range. The estimated mass of the released nanoparticles was 0.06–0.26 g per gram of fabric, which is lower than the amount released during the washing of new textiles. Additionally, Scanning Transmission X-ray Microscopy (STXM) images indicated that the weathered nanoparticles underwent oxidation. Overall, the research offers valuable insights into nanoparticle formation and release from polyester textiles during UV degradation.

Fabrication of 3D Polycaprolactone Macrostructures by 3D Electrospinning.

Building 3D electrospun macrostructures and monitoring the biological activities inside them are challenging. In this study, 3D fibrous polycaprolactone (PCL) macrostructures were successfully fabricated using in-house 3D electrospinning. The main factors supporting the 3D self-assembled nanofiber fabrication are the H3PO4 additives, flow rate, and initial distance. The effects of solution concentration, solvent, H3PO4 concentration, flow rate, initial distance, voltage, and nozzle speed on the 3D macrostructures were examined. The optimal conditions of 4 mL/h flow rate, 4 cm initial nozzle-collector distance, 14 kV voltage, and 1 mm/s nozzle speed provided a rapid buildup of cylinder macrostructures with 6 cm of diameter, reaching a final height of 16.18 ± 2.58 mm and a wall thickness of 3.98 ± 1.01 mm on one perimeter with uniform diameter across different sections (1.40 ± 1.10 μm average). Oxygen plasma treatment with 30-50 W for 5 min significantly improved the hydrophilicity of the PCL macrostructures, proving a suitable scaffold for in vitro cell cultures. Additionally, 3D images obtained by synchrotron radiation X-ray tomographic microscopy (SRXTM) presented cell penetration and cell growth within the scaffolds. This breakthrough in 3D electrospinning surpasses current scaffold fabrication limitations, opening new possibilities in various fields.

Deep understanding of LiCoO2 electrode degradation for optimized recycling strategies

Empowered by a synergistic combination approach of Scanning Transmission X-ray Microscopy (STXM) imaging and X-ray Absorption Near Edge Structure (XANES) spectroscopy, a quantitative analysis on the composition and spatial distribution of the cathode in a failed 18650 LiCoO2 (LCO) battery was conducted. Distinct compositional differences between the central and peripheral cathode regions in the failed LCO battery were discerned by utilizing bulk XANES in Total Electron Yield (TEY) and Fluorescence Yield (FY) modes. The central region shows more severe degradation in terms of LCO reduction and excess cathode-electrolyte interface (CEI) buildup. Meanwhile, the STXM technique precisely imaged a specific region of interest in the center of the cathode, covering C, O, and F K-edges, and Co L2,3-edge, to deeply investigate the degradation. Quantitative chemical mapping with spatially resolved XANES spectroscopy, facilitate an in-depth understating of the interfacial reactions on battery electrodes and battery failure fundamentals.

Controlled Mechanical Property Gradients Within a Digital Light Processing Printed Hydrogel-Composite Osteochondral Scaffold.

Tissue engineered scaffolds are needed to support physiological loads and emulate the micrometer-scale strain gradients within tissues that guide cell mechanobiological responses. We designed and fabricated micro-truss structures to possess spatially varying geometry and controlled stiffness gradients. Using a custom projection microstereolithography (μSLA) system, using digital light projection (DLP), and photopolymerizable poly(ethylene glycol) diacrylate (PEGDA) hydrogel monomers, three designs with feature sizes < 200μm were formed: (1) uniform structure with 1MPa structural modulus ( ) designed to match equilibrium modulus of healthy articular cartilage, (2) = 1MPa gradient structure designed to vary strain with depth, and (3) osteochondral bilayer with distinct cartilage ( = 1MPa) and bone ( = 7MPa) layers. Finite element models (FEM) guided design and predicted the local mechanical environment. Empty trusses and poly(ethylene glycol) norbornene hydrogel-infilled composite trusses were compressed during X-ray microscopy (XRM) imaging to evaluate regional stiffnesses. Our designs achieved target moduli for cartilage and bone while maintaining 68-81% porosity. Combined XRM imaging and compression of empty and hydrogel-infilled micro-truss structures revealed regional stiffnesses that were accurately predicted by FEM. In the infilling hydrogel, FEM demonstrated the stress-shielding effect of reinforcing structures while predicting strain distributions. Composite scaffolds made from stiff μSLA-printed polymers support physiological load levels and enable controlled mechanical property gradients which may improve in vivo outcomes for osteochondral defect tissue regeneration. Advanced 3D imaging and FE analysis provide insights into the local mechanical environment surrounding cells in composite scaffolds.

IDENTIFYING THE ROLE OF ELECTROLYTE ADDITIVES FOR LITHIUM PLATING ON GRAPHITE ELECTRODE BY OPERANDO X‐RAY TOMOGRAPHY

The plating of lithium on the graphite electrode is a major degradation mechanism in lithium‐ion batteries (LIBs) and brings safety concerns and leads to short cycle life. Understanding how and when plating occurs is crucial for the development of mitigation strategies, e.g. tuning the electrolyte composition. We present an operando X‐ray tomographic microscopy study to monitor the plating of lithium on a graphite electrode. XTM enables non‐destructive, quantitative operando characterization of lithium deposition and allows us to probe the role of the electrolyte additives vinylene carbonate and lithium bis(fluorosulfonyl)imide in the standard electrolyte LP57. The additives show a better performances in terms of delayed onset of lithium plating, important to utilise the full capacity of the graphite, since once lithium plating is initiated this rapidly becomes dominating and hinders further intercalation. For the base electrolyte a homogeneous and dense morphology of plated lithium is found, whereas a more dendritic morphology is observed in the presence of additives. During delithiation, there is a rapid stripping of some of the plated lithium followed by deintercalation. In addition, our work provides a general methodology to track the morphology of plated lithium, which is crucial for fundamental research about battery safety.

Multiple energy X-ray imaging of metal oxide particles inside gingival tissues.

Periodontal disease affects over 50% of the global population and is characterized by gingivitis as the initial sign. One dental health issue that may contribute to the development of periodontal disease is foreign body gingivitis (FBG), which can result from exposure to some kinds of foreign metal particles from dental products or food. We design a novel, portable, affordable, multispectral X-ray and fluorescence optical microscopic imaging system dedicated to detecting and differentiating metal oxide particles in dental pathological tissues. A novel denoising algorithm is applied. We verify the feasibility and optimize the performance of the imaging system with numerical simulations. The designed imaging system has a focused X-ray tube with tunable energy spectra and thin scintillator coupled with an optical microscope as detector. A simulated soft tissue phantom is embedded with 2-micron thick metal oxide discs as the imaged object. GATE software is used to optimize the systematic parameters such as energy bandwidth and X-ray photon number. We have also applied a novel denoising method, Noise2Sim with a two-layer UNet structure, to improve the simulated image quality. The use of an X-ray source operating with an energy bandwidth of 5 keV, X-ray photon number of 108, and an X-ray detector with a 0.5 micrometer pixel size in a 100 by 100-pixel array allowed for the detection of particles as small as 0.5 micrometer. With the Noise2Sim algorithm, the CNR has improved substantially. A typical example is that the Aluminum (Al) target's CNR is improved from 6.78 to 9.72 for the case of 108 X-ray photons with the Chromium (Cr) source of 5 keV bandwidth. Different metal oxide particles were differentiated using Contrast-to-Noise ratio (CNR) by utilizing four different X-ray spectra.

Resolving taphonomic and preparation biases in silicified faunas through paired acid residues and X-ray microscopy.

Paired petrography and acid maceration has shown that preferential silicification of shelly faunas can bias recovery based on taxon and body size. Here, silicified fossils from the Upper Ordovician Edinburg Formation, Strasburg Junction, Virginia, USA, were analyzed using X-ray tomographic microscopy (μCT) in conjunction with recovered residues from acid maceration of the same materials to further examine sources of potential bias. Results reveal that very small (<~1 mm) fossils are poorly resolved in μCT when scanning at lower resolutions (~30 µm), underestimating abundance of taxa including ostracods and bryozoans. Acid maceration, meanwhile, fails to recover poorly silicified fossils prone to disarticulation and/or fragmentation during digestion. Tests for patterns of breakage, however, indicate no significant size or taxonomic bias during extraction. Comparisons of individual fossils from 3-D fossil renders and maceration residues reveal patterns of fragmentation that are taxon-specific and allow the differentiation of biostratinomic and preparational breakage. Multivariate ordinations and cluster analyses of μCT and residue data in general produce concordant results but indicate that the variation in taxonomic composition of our samples is compromised by the resolvability of small size classes in μCT imaging, limiting the utility of this method for addressing paleoecological questions in these specific samples. We suggest that comparability of results will depend strongly on the sample size, taphonomic history, textural, and compositional characteristics of the samples in question, as well as μCT scan parameters. Additionally, applying these methods to different deposits will test the general applicability of the conclusions drawn on the relative strengths and weaknesses of the methods.

Laboratory Liquid-Jet X-ray Microscopy and X-ray Fluorescence Imaging for Biomedical Applications.

Diffraction-limited resolution and low penetration depth are fundamental constraints in optical microscopy and in vivo imaging. Recently, liquid-jet X-ray technology has enabled the generation of X-rays with high-power intensities in laboratory settings. By allowing the observation of cellular processes in their natural state, liquid-jet soft X-ray microscopy (SXM) can provide morphological information on living cells without staining. Furthermore, X-ray fluorescence imaging (XFI) permits the tracking of contrast agents in vivo with high elemental specificity, going beyond attenuation contrast. In this study, we established a methodology to investigate nanoparticle (NP) interactions in vitro and in vivo, solely based on X-ray imaging. We employed soft (0.5 keV) and hard (24 keV) X-rays for cellular studies and preclinical evaluations, respectively. Our results demonstrated the possibility of localizing NPs in the intracellular environment via SXM and evaluating their biodistribution with in vivo multiplexed XFI. We envisage that laboratory liquid-jet X-ray technology will significantly contribute to advancing our understanding of biological systems in the field of nanomedical research.

Unveiling the crystal and magnetic texture of iron oxide nanoflowers.

Iron oxide nanoflowers (IONF) are densely packed multi-core aggregates known for their high saturation magnetization and initial susceptibility, as well as low remanence and coercive field. This study reports on how the local magnetic texture originating at the crystalline correlations among the cores determines the special magnetic properties of individual IONF over a wide size range from 40 to 400 nm. Regardless of this significant size variation in the aggregates, all samples exhibit a consistent crystalline correlation that extends well beyond the IONF cores. Furthermore, a nearly zero remnant magnetization, together with the presence of a persistently blocked state, and almost temperature-independent field-cooled magnetization, support the existence of a 3D magnetic texture throughout the IONF. This is confirmed by magnetic transmission X-ray microscopy images of tens of individual IONF, showing, in all cases, a nearly demagnetized state caused by the vorticity of the magnetic texture. Micromagnetic simulations agree well with these experimental findings, showing that the interplay between the inter-core direct exchange coupling and the demagnetizing field is responsible for the highly vortex-like spin configuration that stabilizes at low magnetic fields and appears to have partial topological protection. Overall, this comprehensive study provides valuable insights into the impact of crystalline texture on the magnetic properties of IONF over a wide size range, offering a deeper understanding of their potential applications in fields such as biomedicine and water remediation.