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Bone sections including either titanium or porous tantalum implant devices used for interbody spinal fusion were investigated with position-resolved small angle X-ray scattering (sSAXS). The samples were obtained from six-month-old pigs that had undergone surgery three months prior to sacrifice. The aim of the study was to explore the possibility of using sSAXS to obtain information about thickness, orientation and shape/arrangement of the mineral crystals in bone near the implant surfaces. Detailed sSAXS scans were carried out in two different regions of bone adjacent to the implant in each of the implant samples. In the implant vicinity the mineral crystals tended to be aligned with the surface of the implants. The mean crystal thickness was between 2.1 and 3.0 nm. The mineral crystal thickness increased linearly with distance from the implant in both regions of the porous tantalum implant and in one of the regions in the titanium sample. In the second region of the titanium sample the thickest mineral crystals were found close to the implant surface. The observed differences in mineral thickness with distance from the implant surfaces might be explained by differences in mechanical load induced by the implant material and the geometrical design of the implant. The study shows that sSAXS is a powerful tool to characterize the nanostructure of bone near implant surfaces.

The chronic performance of implantable neural prostheses is affected by the growth of encapsulation tissue onto the stimulation electrodes. Encapsulation is associated with activation of connective tissue cells at the electrode's metallic contacts, usually made of platinum. Since surface nanotopography can modulate the cellular responses to materials, the aim of the present work was to evaluate the 'in vitro' responses of connective tissue cells to platinum strictly by modulating its surface nanoroughness. Using molecular beam epitaxy combined with sputtering, we produced platinum nanostructured substrates consisting of irregularly distributed nanopyramids and investigated their effect on the proliferation, cytoskeletal organization and cellular morphology of primary fibroblasts and transformed glial cells. Cells were cultured on these substrates and their responses to surface roughness were studied. After one day in culture, the fibroblasts were more elongated and their cytoskeleton less mature when cultured on rough substrates. This effect increased as the roughness of the surface increased and was associated with reduced cell proliferation throughout the observation period (4 days). Morphological changes also occurred in glial cells, but they were triggered by a different roughness scale and did not affect cellular proliferation. In conclusion, surface nanotopography modulates the responses of fibroblasts and glial cells to platinum, which may be an important factor in optimizing the tissue response to implanted neural electrodes. [ABSTRACT FROM AUTHOR]

We have used the glancing angle deposition (GLAD) method as a simple and fast method to generate nano-rough surfaces for protein adsorption experiments and cell assays. The surface roughness and the detailed geometrical surface morphology of the thin films were characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). As the GLAD deposition angle approaches grazing incidence, sharp and whisker-like columnar protrusions are formed. Smaller and less sharp surface features appear for the thin films synthesized at higher deposition angles. By changing the GLAD deposition angle together with the total amount of mass deposited per area on the respective surfaces, the size of the surface features can be varied on the nanoscale. Using the GLAD topographies as model surfaces, we have investigated the influence of the nano-roughness on fibrinogen adsorption and on the proliferation of primary human fibroblasts. It is found that fibrinogen, an important blood protein, preferentially adheres on the whisker-like nano-rough substrates in comparison to a flat surface. Furthermore, the proliferation of the human fibroblasts is significantly reduced on the nano-rough substrates. These results demonstrate that the GLAD technique can be used to fabricate nano-rough surface morphologies that significantly influence both protein and cellular adhesion to surfaces and are therefore well suited for biological assays. [ABSTRACT FROM AUTHOR]

We studied the nucleation of gold clusters on TiO2(110) surfaces in three different oxidation states by high-resolution scanning tunneling microscopy. The three TiO2(110) supports chosen were (i) reduced (having bridging oxygen vacancies), (ii) hydrated (having bridging hydroxyl groups), and (iii) oxidized (having oxygen adatoms). At room temperature, gold nanoclusters nucleate homogeneously on the terraces of the reduced and oxidized supports, whereas on the hydrated TiO2(110) surface, clusters form preferentially at the step edges. From interplay with density functional theory calculations, we identified two different gold-TiO2(110) adhesion mechanisms for the reduced and oxidized supports. The adhesion of gold clusters is strongest on the oxidized support, and the implications of this finding for catalytic applications are discussed. [ABSTRACT FROM AUTHOR]

The role of tumor-resident intracellular microbiota (TRIM) in carcinogenesis has sparked enormous interest. Nevertheless, the impact of TRIM-targeted antibacteria on tumor inhibition and immune regulation in the tumor microenvironment (TME) remains unexplored. Herein, we report long-term relapse-free survival by coordinating antibacteria with antitumor treatment, addressing the aggravated immunosuppression and tumor overgrowth induced by TRIM using breast and prostate cancer models. Combining Ag + release with a Fenton-like reaction and photothermal conversion, simultaneous bacteria killing and multimodal antitumor therapy are enabled by a single agent. Free of immune-stimulating drugs, the agent restores antitumor immune surveillance and activates immunological responses. Secondary inoculation and distal tumor analysis confirm lasting immunological memory and systemic immune responses. A relapse-free survival of >700 days is achieved. This work unravels the crucial role of TRIM-targeted antibacteria in tumor inhibition and unlocks an unconventional route for immune regulation in TME and a complete cure for cancer., (© 2024. The Author(s).)

Heterogeneous catalytic ammoxidation provides an eco-friendly route for the cyanide-free synthesis of nitrile compounds, which are important precursors for synthetic chemistry and pharmaceutical applications. However, in general such a process requires high pressures of molecular oxygen at elevated temperatures to accelerate the oxygen reduction and imine dehydrogenation steps, which is highly risky in practical applications. Here, we report an electric field enhanced ammoxidation system using a supported Fe clusters catalyst (Fe/NC), which enables efficient synthesis of nitriles from the corresponding aldehydes under ambient air pressure at room temperature (RT). A synergistic effect between the external electric field and the Fe/NC catalyst promotes the ammonia activation and the dehydrogenation of the generated imine intermediates and avoids the unwanted backwards reaction to aldehydes. This electric field enhanced ammoxidation system presents high efficiency and selectivity for the conversion of a series of aldehydes under mild conditions with high durability, rendering it an attractive process for the green synthesis of nitriles with fragile functional groups., (© 2023 Wiley-VCH GmbH.)

As an efficient molecular engineering approach, on-surface synthesis (OSS) defines a special opportunity to investigate intermolecular coupling at the sub-molecular level and has delivered many appealing polymers. So far, all OSS is based on the lateral covalent bonding of molecular precursors within a single molecular layer; extending OSS from two to three dimensions is yet to be realized. Herein, we address this challenge by cycloaddition between C 60 and an aromatic compound. The C 60 layer is assembled on the well-defined molecular network, allowing appropriate molecular orbital hybridization. Upon thermal activation, covalent coupling perpendicular to the surface via [4 + 2] cycloaddition between C 60 and the phenyl ring of the molecule is realized; the resultant adduct shows frozen orientation and distinct sub-molecular feature at room temperature and further enables lateral covalent bonding via [2 + 2] cycloaddition. This work unlocks an unconventional route for bottom-up precise synthesis of three-dimensional covalently-bonded organic architectures/devices on surfaces., (© 2023. Springer Nature Limited.)

Environmental-friendly halogenation of C-H bonds using abundant, non-toxic halogen salts is in high demand in various chemical industries, yet the efficiency and selectivity of laboratory available protocols are far behind the conventional photolytic halogenation process which uses hazardous halogen sources. Here we report an FeX 2 (X=Br, Cl) coupled semiconductor system for efficient, selective, and continuous photocatalytic halogenation using NaX as halogen source under mild conditions. Herein, FeX 2 catalyzes the reduction of molecular oxygen and the consumption of generated oxygen radicals, thus boosting the generation of halogen radicals and elemental halogen for direct halogenation and indirect halogenation via the formation of FeX 3 . Recycling of FeX 2 and FeX 3 during the photocatalytic process enables the halogenation of a wide range of hydrocarbons in a continuous flow, rendering it a promising method for applications., (© 2023 Wiley-VCH GmbH.)

Heterogeneous photocatalysis is effective for the selective synthesis of value-added chemicals at lab-scale, yet falls short of requirements for mass production (low cost and user friendliness). Here we report the design and fabrication of a modular tubular flow system embedded with replaceable photocatalyst membranes for scalable photocatalytic C-C, C-N homocoupling and hydrogenation reactions, which can be operated in either circular and continuous flow mode with high performance. The photocatalyst membranes almost fully occupy the volume of the reactor, thus enabling optimal absorption of the incident light. Additionally, the porous structured photocatalyst membranes facilitate the mass transfer of the reactants to efficiently use the active sites, resulting in 0 th -order reaction kinetics and a high space-time yield compared to the batch reaction system at practical application levels and prolonged reaction times., (© 2023 Wiley-VCH GmbH.)

Halide perovskite materials, especially lead-based perovskites, have been widely used for optoelectronic and catalytic applications. However, the high toxicity of the lead element is a major concern that directs the research work toward lead-free halide perovskites, which could utilize bismuth as a promising candidate. Until now, the replacement of lead by bismuth in perovskites has been well studied by designing bismuth-based halide perovskite (BHP) nanomaterials with versatile physical-chemical properties, which are emerging in various application fields, especially heterogeneous photocatalysis. In this mini-review, we present a brief overview of recent progress in BHP nanomaterials for photocatalysis under visible light. The synthesis and physical-chemical properties of BHP nanomaterials have been comprehensively summarized, including zero-dimensional, two-dimensional nanostructures and hetero-architectures. Later, we introduce the photocatalytic applications of these novel BHP nanomaterials with visible-light response, improved charge separation/transport and unique catalytic sites. Due to advanced nano-morphologies, a well-designed electronic structure and an engineered surface chemical micro-environment, BHP nanomaterials demonstrate enhanced photocatalytic performance for hydrogen generation, CO 2 reduction, organic synthesis and pollutant removal. Finally, the challenges and future research directions of BHP nanomaterials for photocatalysis are discussed.

Photocatalysis provides an eco-friendly route for the hydrogenation of aromatic carbonyls to O-free aromatics, which is an important refining process in the chemical industry that is generally carried out under high pressure of hydrogen at elevated temperatures. However, aromatic carbonyls are often only partially hydrogenated to alcohols, which readily desorbs and are hardly further deoxygenated under ambient conditions. Here, we show that by constructing an oxide surface over the Pd cocatalyst supported on graphitic carbon nitride, an alternative hydrogenation path of aromatic carbonyls becomes available via a step-wise acetalization and hydrogenation, thus allowing efficient and selective production of O-free aromatics. The PdO surface allows for optimum adsorption of reactants and intermediates and rapid abstraction of hydrogen from the alcohol donor, favoring fast acetalization of the carbonyls and their consecutive hydrogenation to O-free hydrocarbons. The photocatalytic hydrogenation of benzaldehyde into toluene shows a high selectivity of >90% and a quantum efficiency of ∼10.2% under 410 nm irradiation. By adding trace amounts of HCl to the reaction solution, the PdO surface remains stable and active for long-term operation at high concentrations, offering perspective for practical applications.

As a typical tumor microenvironment-responsive therapy, chemodynamic therapy (CDT), producing hydroxyl radicals ( • OH) to eliminate tumor cells, has demonstrated great promise. Nevertheless, there are still major challenges: • OH generated from endogenous H 2 O 2 is usually insufficient; the CDT effect is strongly dependent on the pre-reaction with glutathione. Addressing the challenges, Au@MnSe 2 core-shell nanoagent for synergetic chemodynamic-photothermo-photocatalytic therapy combined with tetramodal imaging, including magnetic resonance imaging, computed tomography, photoacoustic, and infrared thermal imaging is reported. Distinct from the reported glutathione-depleting agents, Mn 2+ in MnSe 2 allows immediate generation of • OH, independent of pre-reaction. Meanwhile, Mn 3+ consumes glutathione by its conversion to Mn 2+ . The Au-MnSe 2 combination promotes photothermal conversion and photocatalytic reaction, resulting in largely enhanced • OH generation from endogenous H 2 O 2 and significant hyperthermia. Meanwhile, immune response is effectively activated: the intratumoral expression of programmed cell death-1 and proinflammatory cytokines increase to 4-7 folds; the cytotoxic and helper T lymphocytes cells in the tumor area increase to more than 2.5-folds; an evident, temporary systemic immunostimulatory effect is demonstrated. High tumor inhibition rate (≈97.3%) and greatly prolonged survival are obtained. This highly-integrated design coordinating three different therapies with four different imaging modals provide new possibilities for high-performance theranostic nanoagents., (© 2022 Wiley-VCH GmbH.)

Employing pure water, the ultimate green source of hydrogen donor to initiate chemical reactions that involve a hydrogen atom transfer (HAT) step is fascinating but challenging due to its large H-O bond dissociation energy (BDE H-O =5.1 eV). Many approaches have been explored to stimulate water for hydrogenative reactions, but the efficiency and productivity still require significant enhancement. Here, we show that the surface hydroxylated graphitic carbon nitride (gCN-OH) only requires 2.25 eV to activate H-O bonds in water, enabling abstraction of hydrogen atoms via dehydrogenation of pure water into hydrogen peroxide under visible light irradiation. The gCN-OH presents a stable catalytic performance for hydrogenative N-N coupling, pinacol-type coupling and dehalogenative C-C coupling, all with high yield and efficiency, even under solar radiation, featuring extensive impacts in using renewable energy for a cleaner process in dye, electronic, and pharmaceutical industries., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

A widely accepted theory is that life originated from the hydrothermal environment in the primordial ocean. Nevertheless, the low desorption temperature from inorganic substrates and the fragileness of hydrogen-bonded nucleobases do not support the required thermal stability in such an environment. Herein, we report the super-robust complexes of xanthine, one of the precursors for the primitive nucleic acids, with Na. We demonstrate that the well-defined xanthine-Na complexes can only form when the temperature is ≥430 K, and the complexes keep adsorbed even at ≈720 K, presenting as the most thermally stable organic polymer ever reported on Au(111). This work not only justifies the necessity of high-temperature, Na-rich environment for the prebiotic biosynthesis but also reveals the robustness of the xanthine-Na complexes upon the harsh environment. Moreover, the complexes can induce significant electron transfer with the metal as inert as Au and hence lift the Au atoms up., (© 2022 Wiley-VCH GmbH.)

Transition-metal carbides have sparked unprecedented enthusiasm as high-performance catalysts in recent years. Still, the catalytic properties of copper carbide remain unexplored. By introducing subsurface carbon to Cu(111), a displacement reaction of a proton in a carboxyl acid group with a single Cu atom is demonstrated at the atomic scale and room temperature. Its occurrence is attributed to the C-doping-induced local charge of surface Cu atoms (up to +0.30 e/atom), which accelerates the rate of on-surface deprotonation via reduction of the corresponding energy barrier, thus enabling the instant displacement of a proton with a Cu atom when the molecules adsorb on the surface. This well-defined and robust Cu δ+ surface based on subsurface-carbon doping offers a novel catalytic platform for on-surface synthesis., (© 2021 Wiley-VCH GmbH.)

Thanks to the low cost, free dendritic hazards, and high volumetric capacity, magnesium (Mg)-ion batteries have attracted increasing attention as alternative energy storage devices to lithium-ion batteries. Despite the successful development of electrode materials, the real-life application potential of Mg-ion full battery systems (MIFBSs) is largely hindered by the lack of suitable electrode couples and hence low diffusion kinetics, which induce low specific capacity, poor rate performance, and low working voltage. Herein, we report an aqueous rechargeable MIFBS by employing copper hexacyanoferrate (CuHCF) as the cathode and 3,4,9,10-perylene-tetracarboxylic acid diimide (PTCDI) as the anode in 1 moL L -1 MgCl 2 electrolyte. The combination of PTCDI//CuHCF allows efficient redox and convenient intercalation/deintercalation of Mg 2+ at the electrodes while facilitating a fast transfer of Mg 2+ between the two electrodes. As a result, the system delivers a high capacity of ∼120.3 mAh g -1 at a current density of 0.5 A g -1 after 200 operation cycles with a broadened voltage range (0-1.95 V) and maintains a capacity of ∼97.8 mAh g -1 at 2.0 A g -1 after 1000 cycles. Even at a high current density of 5.0 A g -1 , the battery provides a steady capacity of ∼81.4 mAh g -1 over 5000 cycles. Moreover, after being applied at 11.0 A g -1 , the system can deliver a capacity of ∼126.5 mAh g -1 at 0.5 A g -1 . This work emphasizes the great promise of developing suitable electrode couples for aqueous MIFBSs to achieve high capacity and high rate.