The morphology, nanostructures, and crystallinity of hydroxyapatite (HA) materials have significant effects on their physicochemical properties and biomedical applications. However, the controllable synthesis of HA nanomaterials with various size and morphology using the same synthesis system, though desirable, has remained a challenge. In this work, we successfully synthesized HA nanomaterials with different morphologies via a one-step solvothermal route in the same reaction system. By using (NaPO₃)₃, Na₃PO₄·12H₂O and NaH₂PO₄·2H₂O as phosphorus sources, the growth of HA crystals was regulated, resulting in the transformation of HA nanomaterials morphology from nanorods to nanowires. Different concentrations of PO₄³⁻ and OH⁻ ions in the reaction environments regulated by different phosphates lead to different nanostructures of HA crystals. Our work provides an instructive way to controllably fabricate HA nanomaterials with various morphologies and will widen the biomedical applications of HA materials.

Carbonated hydroxyapatite (CHA) microspheres have aroused wide concern in biofields because of their excellent biological and surface properties. However, the facile preparation of CHA microspheres from organic compounds, especially the microstructural transformation during synthesis, has been rarely reported. In this work, CHA microspheres with an average diameter of 2.528 μm and a BET surface area of 51.0658 m²/g were synthesized via a one-pot hydrothermal method at 180 °C for 10 h by using calcium chloride, diammonium hydrogen phosphate, urea, and trisodium citrate (TSC) with a molar ratio of TSC to Ca of 1:2. The effects of hydrothermal treatment temperature and molar ratio of TSC to Ca on the morphology of the products were investigated. As a chelating agent, TSC is crucial to the formation of CHA microspheres during the hydrothermal homogeneous precipitation process. A possible mechanism of the microstructural transformation from bundle to dumbbell, dumbbell ball, and finally, microspheres regulated by TSC and urea was proposed. The CHA microspheres can be used as effective drug carriers for biomedical applications.

Porous hydroxyapatite HA microspheres with a core–shell structure are crystallized via dissolution and re-crystallization of smooth amorphous calcium phosphate microspheres.

Bone defects pose a significant risk to human health. Medical polyetheretherketone (PEEK) is an excellent implant material for bone defect repair, but it faces the challenge of bone osteoconduction and osseointegration. Osteoconduction describes the process by which bone grows on the surface of the implant, while osseointegration is the stable anchoring of the implant achieved by direct contact between the bone and the implant. Bone defects repair depends on the implant’s three-dimensional spatial structure, including pore size, porosity, and interconnections to a great extent. However, it is challenging to fabricate the porous structures to meet specific requirements and to characterize them without causing damage. In this study, we designed and fabricated sandwich-like PEEK implants mimicking the three-layer structures of the skull, whose defects imposes a significant burden on young adulthood and paediatric populations, and performed in-line phase-contrast synchrotron X-ray microtomography to non-destructively investigate the internal porous microstructures. The sandwich-like three-layer microstructure, comprising a dense layer, a loose layer and a dense layer in succession, exhibits structural similarity to that in a natural skull. This work demonstrated the fabrication of the sandwich-like PEEK implant that could potentially enhance osteoconduction and osseointegration. Furthermore, the interior structures and residual porogen sodium chloride particles were observed within the PEEK implant, which cannot be realized by other microscopic methods without destroying the sample. It highlights the advantages and potential of using synchrotron X-ray microtomography to analyze the structure of biomedical materials. This study provides theoretical guidance for the further design and fabrication of PEEK bone repair materials and will advance the clinical application of innovative bioactive bone repair materials.

In common ptychographic coherent diffractive imaging (PCDI) systems, the probe-generating devices typically exhibit strong scattering, which is not fully used. Here, we report the reasonableness of using the diffraction pattern of the probe-generating device as the frequency-domain information of the scanning probe located in the sample plane, and we propose a method introducing this frequency-domain information into an iterative process to improve the imaging quality of PCDI. The new method was demonstrated using both a visible laser source and a synchrotron radiation X-ray source; the proposed method significantly improved the imaging quality in both demonstrations.

Zirconia (ZrO₂) aerogels show excellent insulating performance and have been widely applied as a thermal protector in furnaces, nuclear reactors, and spacecraft. The nondestructive determination of their interior microstructure is significant for evaluating their mechanical and insulating performance. In this study, we performed nondestructive structural investigation of an yttria-stabilized ZrO₂ fiber insulation tile using synchrotron X-ray in-line phase-contrast microtomography at a pixel resolution of 6.5 µm. Taking advantage of the edge enhancement of phase-contrast imaging, single yttria-stabilized ZrO₂ fibers were clearly distinguished; furthermore, interior aggregates were nondestructively observed at this spatial resolution. This work demonstrates the advantages and potential of synchrotron X-ray microtomography for the structural analysis of porous ceramic materials. By combining higher-brilliance synchrotron radiation sources and CCD detectors with higher spatial and temporal resolutions, we anticipate that we can further understand the relationship between aerogel microstructure and function, especially under in-service conditions at high temperatures.