Calcium phosphate (CaP) nanoparticles are promising and well-studied nanocarriers for drug and antigen delivery due to their biocompatibility, biodegradability, and tunable properties. However, their scalable and reproducible synthesis with tunable biological response remains a challenge. Flame spray pyrolysis (FSP) offers a single-step, scalable approach for producing nanoparticles with tunable composition, crystallinity, and size. In this study, we utilized this versatile method to synthesize amorphous CaP nanoparticles with varying SiO2 content (16, 36, 62 wt%) and investigated how SiO2 incorporation affects their structural, colloidal and functional properties. Structural analysis (X-Ray Diffraction, Fourier Transform-Infrared Spectroscopy, and electron microscopy with elemental mapping) confirmed successful SiO2 incorporation up to 16 wt% with no SiO2 segregation while maintaining the amorphous nature of CaP. Dissolution studies demonstrated a pH-dependent release profile, supporting their potential for controlled biological drug (ovalbumin) delivery in acidic environments. SiO2 addition drastically reduced the nanoparticle hydrodynamic size, as well as the surface charge, which in turn impacted ovalbumin loading, delivery, and dendritic cell (DC) activation. Pure CaP nanoparticles exhibited the highest drug loading (-400 mu g/mg) and significantly enhanced ovalbumin delivery to DCs (-2.2 fold), leading to robust antigen processing and upregulation of co-stimulatory markers (CD86, CD80, CD40) and major histocompatibility complex (MHC) class II molecules. In contrast, SiO2 containing formulations improved colloidal stability and reduced immune activation, indicating their potential as non-immunogenic stealth nanocarriers for delivery applications. Overall, this study highlights the versatility of flame-made amorphous CaP-SiO2 nanoparticles for tailored immunomodulation and drug delivery applications.

A suite of acquisition applications related to the 4D-STEM technique is presented as a software package written within the Digital Micrograph environment, which is a widely used software platform in worldwide electron microscopy laboratories. The 4D-STEM technique allows the acquisition of diffraction patterns at each electron probe position in a scanning transmission electron microscope map. This suite includes 4D-STEM acquisition, ptychography, EELS/EDS spectrum imaging, tomography and basic virtual visualization and alignment methods on 4D data including incoherent differential phase contrast analysis. By integrating electron tomography with 4D-STEM and EELS SI, St4DeM enables the acquisition and analysis of 7-dimensional data.

Due to their high potential energy storage magnetite (Fe3O4) nanoparticles have become appealing for anode materials in lithium-ion batteries. However, the details of the lithiation process are still not completely understood. Here, we investigate chem- ical lithiation in 70 nm cubic shaped magnetite nanoparticles with varying degree of lithiation x = 0, 0.5, 1, 1.5. The induced changes on the structural and magnetic properties were investigated by using X-ray techniques along with electron microscopy and magnetic measurements. The results indicate that a structural transformation from spinel to rock salt phase occurs above a critical limit for the lithium concentra- tion (xc), which is determined to be between 0.5< xc≤1 for Fe3–δO4. Magnetization measurements clearly shows the formation of the LiFeO2 phase with its distinct anti- ferromagnetic behaviour below its Need temperature. Upon lithiation, magnetization measurements reveal exchange bias in the hysteresis loops with an asymmetry, which can be attributed to the formation of mosaic-like LiFeO2 subdomains. The combined characterization techniques enabled us to unambiguously identify the phases and their distribution involved in the lithiation process. Correlating magnetic and structural properties opens the path to increase the understanding of the processes involved in a variety of non-magnetic applications of magnetic materials.

Implant infections are a major challenge for the healthcare system. Biofilm formation and increasing antibiotic resistance of common bacteria cause implant infections, leading to an urgent need for alternative antibacterial agents. In this study, the antibiofilm behaviour of a coating consisting of a silver (Ag)/gold (Au) nanoalloy is investigated. This alloy is crucial to reduce uncontrolled potentially toxic Ag+ ion release. In neutral pH environments this release is minimal, but the Ag+ ion release increases in acidic microenvironments caused by bacterial biofilms. We perform a detailed physicochemical characterization of the nanoalloys and compare their Ag+ ion release with that of pure Ag nanoparticles. Despite a lower released Ag+ ion concentration at pH 7.4, the antibiofilm activity against Escherichia coli (a bacterium known to produce acidic pH environments) is comparable to a pure nanosilver sample with a similar Ag-content. Finally, biocompatibility studies with mouse pre-osteoblasts reveal a decreased cytotoxicity for the alloy coatings and nanoparticles.

Lithium-rich, cobalt-free oxides are promising potential positive electrode materials for lithium-ion batteries because of their high energy density, lower cost, and reduced environmental and ethical concerns. However, their commercial breakthrough is hindered because of their subpar electrochemical stability. This work studies the effect of aluminum doping on Li1.26Ni0.15Mn0.61O2 as a lithium-rich, cobalt-free layered oxide. Al doping suppresses voltage fade and improves the capacity retention from 46% for Li1.26Ni0.15Mn0.61O2 to 67% for Li1.26Ni0.15Mn0.56Al0.05O2 after 250 cycles at 0.2 C. The undoped material has a monoclinic Li2MnO3-type structure with spinel on the particle edges. In contrast, Al-doped materials (Li1.26Ni0.15Mn0.61-xAlxO2) consist of a more stable rhombohedral phase at the particle edges, with a monoclinic phase core. For this core-shell structure, the formation of Mn3+ is suppressed along with the material's decomposition to a disordered spinel, and the amount of the rhombohedral phase content increases during galvanostatic cycling. Whereas previous studies generally provided qualitative insight into the degradation mechanisms during electrochemical cycling, this work provides quantitative information on the stabilizing effect of the rhombohedral shell in the doped sample. As such, this study provides fundamental insight into the mechanisms through which Al doping increases the electrochemical stability of lithium-rich cobalt-free layered oxides. This study investigates the impact of aluminum doping on Li1.26Ni0.15Mn0.61O2, a lithium-rich, cobalt-free layered oxide. The undoped material has a monoclinic structure, while the Al-doped materials contain a more stable rhombohedral phase at the particle edges. This work quantitatively elucidates the stabilizing effect of the rhombohedral shell, shedding light on mechanisms that enhance the electrochemical stability of lithium-rich layered oxides. image

Magnetic hyperthermia holds significant therapeutic potential, yet its clinical adoption faces challenges. One obstacle is the large-scale synthesis of high-quality superparamagnetic iron oxide nanoparticles (SPIONs) required for inducing hyperthermia. Robust and scalable manufacturing would ensure control over the key quality attributes of SPIONs, and facilitate clinical translation and regulatory approval. Therefore, we implemented a risk-based pharmaceutical quality by design (QbD) approach for SPION production using flame spray pyrolysis (FSP), a scalable technique with excellent batch-to-batch consistency. A design of experiments method enabled precise size control during manufacturing. Subsequent modeling linked the SPION size (6-30 nm) and composition to intrinsic loss power (ILP), a measure of hyperthermia performance. FSP successfully fine-tuned the SPION composition with dopants (Zn, Mn, Mg), at various concentrations. Hyperthermia performance showed a strong nonlinear relationship with SPION size and composition. Moreover, the ILP demonstrated a stronger correlation to coercivity and remanence than to the saturation magnetization of SPIONs. The optimal operating space identified the midsized (15-18 nm) Mn0.25Fe2.75O4 as the most promising nanoparticle for hyperthermia. The production of these nanoparticles on a pilot scale showed the feasibility of large-scale manufacturing, and cytotoxicity investigations in multiple cell lines confirmed their biocompatibility. In vitro hyperthermia studies with Caco-2 cells revealed that Mn0.25Fe2.75O4 nanoparticles induced 80% greater cell death than undoped SPIONs. The systematic QbD approach developed here incorporates process robustness, scalability, and predictability, thus, supporting the clinical translation of high-performance SPIONs for magnetic hyperthermia.

Silicon powder kerf loss from diamond wire sawing in the photovoltaic wafering industry is a highly appealing source material for use in lithium-ion battery negative electrodes. Here, it is demonstrated for the first time that the kerf particles from three independent sources contain ~50 % amorphous silicon. The crystalline phase is in the shape of nano-scale crystalline inclusions in an amorphous matrix. From literature on wafering technology looking at wafer quality, the origin and mechanisms responsible for the amorphous content in the kerf loss powder are explained. In order to better understand for which applications the material could be a valuable raw material, the amorphicity and other relevant features are thoroughly investigated by a large amount of experimental methods. Furthermore, the kerf powder was crystallized and compared to the partly amorphous sample by operando X-ray powder diffraction experiments during battery cycling, demonstrating that the powders are relevant for further investigation and development for battery applications.

Ruthenium containing molecular electrocatalyst onto pyridine modified, fluorine-doped carbon cloth represents an efficient, bifunctional, and regenerable electrode for water electrolysis at pH 7.

The need to acquire multiple angle-resolved electron energy loss spectra (EELS) is one of the several critical challenges associated with electron magnetic circular dichroism (EMCD) experiments. If the experiments are performed by scanning a nanometer to atomic-sized electron probe on a specific region of a sample, the precision of the local magnetic information extracted from such data highly depends on the accuracy of the spatial registration between multiple scans. For an EMCD experiment in a 3-beam orientation, this means that the same specimen area must be scanned four times while keeping all the experimental conditions same. This is a non-trivial task as there is a high chance of morphological and chemical modification as well as non-systematic local orientation variations of the crystal between the different scans due to beam damage, contamination and spatial drift. In this work, we employ a custom-made quadruple aperture to acquire the four EELS spectra needed for the EMCD analysis in a single electron beam scan, thus removing the above-mentioned complexities. We demonstrate a quantitative EMCD result for a beam convergence angle corresponding to sub-nm probe size and compare the EMCD results for different detector geometries.

Pesticide residues in food products cause human health concerns through food contamination, thereby necessitating their rapid and facile detection. Although surface-enhanced Raman scattering (SERS) technique can rapidly and reliably detect pesticide residues, its application in food safety diagnostics is restricted by its high expense, low scalability, and low reproducibility of the necessary sensors. Herein, we present a low-cost, largescale, and highly reproducible nanofabrication route for SERS nano-sensors, based on the thermophoresisassisted direct deposition of plasmonic core-shell structured Ag-SiO2 nanoparticles produced in the gas phase, on temperature-controlled inexpensive glass substrates. The high-performance SERS substrates were fabricated at a laboratory production rate of 100 samples/hour, demonstrating the scalability and cost-effectiveness of our aerosol manufacturing strategy. Our highly sensitive SERS substrates rapidly and quantitatively detected pesticide residues in fresh orange, indicating their practical applicability for food safety diagnostics.

Electron magnetic circular dichroism (EMCD) is a powerful technique for estimating element-specific magnetic moments of materials on nanoscale with the potential to reach atomic resolution in transmission electron microscopes. However, the fundamentally weak EMCD signal strength complicates quantification of magnetic moments, as this requires very high precision, especially in the denominator of the sum rules. Here, we employ a statistical resampling technique known as bootstrapping to an experimental EMCD dataset to produce an empirical estimate of the noise-dependent error distribution resulting from application of EMCD sum rules to bcc iron in a 3-beam orientation. We observe clear experimental evidence that noisy EMCD signals preferentially bias the estimation of magnetic moments, further supporting this with error distributions produced by Monte-Carlo simulations. Finally, we propose guidelines for the recognition and minimization of this bias in the estimation of magnetic moments.

Bacterial biofilms on medical devices may result in infections with significant societal burden. One drug-free strategy against biofilms is photocatalysis, in which a semiconducting coating is applied on the medical device and irradiated with light to generate reactive oxygen species providing an on-demand disinfection approach. However, most photocatalytic materials are active in the harmful UV range rendering them unsuitable for biomedical applications. Furthermore, the main manufacturing bottleneck today for antibiofilm coatings is their poor durability. To address these challenges, here we produced silver/titanium-suboxide nanoparticles that are photocatalytically active in the visible-light range. Moreover, we directly deposited the nanoparticles as porous coatings on substrates in situ during their aerosol synthesis. To enhance their durability, we infused the fabricated porous coatings with a polymer solution barely covering the photocatalytic particle film, resulting in the formation of polymer nanocomposite coatings. The optimized polymer nanocomposite films exhibit several cycles of triggered, on-demand biofilm eradication activity under short visible light illumination of 15-90 min with no significant intrinsic cytotoxicity to mammalian cells. The developed films can be considered as a suitable coating material for medical devices, such as catheters, ventilators, wound meshes, and others, that may require repeated disinfection during use.

Despite significant potential as energy storage materials for electric vehicles due to their combination of high energy density per unit cost and reduced environmental and ethical concerns, Co‐free lithium ion batteries based on layered Mn oxides presently lack the longevity and stability of their Co‐containing counterparts. Here, a reduction in this performance gap is demonstrated via chemical doping, with Li 1.1 Ni 0.35 Mn 0.54 Al 0.01 O 2 achieving an initial discharge capacity of 159 mAhg −1 at C/3 rate and a corresponding capacity retention of 94.3% after 150 cycles. The nanoscale origins of this improvement are subsequently explored through a combination of advanced diffraction, spectroscopy, and electron microscopy techniques, finding that optimized doping profiles lead to an improved structural and chemical compatibility between the two constituent sub‐phases that characterize the layered Mn oxide system, resulting in the formation of unobstructed lithium ion pathways between them. A structural stabilization effect of the host compound is also directly observed near the surface using aberration corrected scanning transmission electron microscopy and integrated differential phase contrast imaging.

We have investigated the chemical lithiation in 70 nm cubic-shaped magnetite nanoparticles with varying degree of lithiation x = 0, 0.5, 1, 1.5. The induced changes on structure and magnetic properties were investigated with X-ray scattering techniques along with electron microscopy and magnetic measurements. The results indicate that a structural transformation from spinel to rock salt phase occurs above a critical limit for the lithium concentration (xc), which is determined to be between 0.5< xc≤1 for Fe3–δO4. Magnetization measurements confirm the formation of the LiFeO2 phase with its distinct antiferromagnetic behaviour. Upon lithiation, exchange bias measurements reveal a shift in the hysteresis loops with an asymmetry, which can be attributed to the formation of mosaic-like LiFeO2 subdomains and cationic disorder. The combined structural, spectral-imaging and magnetization characterization techniques enabled us to identify the phases and their distribution during in the lithiation process.

TiO2-II is a high pressure form of titania with a density about 2% larger than that of rutile. In contrast to the common polymorphs anatase, brookite and rutile its electronic structure and optical properties are poorly characterized. Here we report on a comparative electron-energy-loss-spectroscopy (EELS) study for which high resolution valence-loss and core-loss EELS data were acquired from nanocrystalline (<75 nm sized) titania particles with an energy resolution of about 0.2 eV. Electronic structure features revealed from titanium L3,2 and oxygen K electron energy loss near-edge structures show a strong similarity of TiO2-II with both rutile and brookite, which is attributed to similarities in the connectivity of octahedral TiO6 units with neighboring ones. From combined valence-loss EELS and UV-VIS diffuse reflectance spectroscopy data the band gap of TiO2-II was determined to be indirect and with a magnitude of-3.18 eV, which is very similar to anatase (indirect,-3.2 eV), and distinctly different from rutile (direct,-3.05 eV) and brookite (direct,-3.45 eV).

Near-infrared (NIR) photothermal therapy by microneedles (MNs) exhibits high potential against skin diseases. However, high costs, photobleaching of organic agents, low long-term stability, and potential nanotoxicity limit the clinical translation of photothermal MNs. Here, photothermal MNs are developed by utilizing Au nanoaggregates made by flame aerosol technology and incorporated in water-insoluble polymer matrix to reduce intradermal nanoparticle (NP) deposition. The individual Au interparticle distance and plasmonic coupling within the nanoaggregates are controlled by the addition of a spacer during their synthesis rendering the Au nanoaggregates highly efficient NIR photothermal agents. In situ aerosol deposition of Au nanoaggregates on MN molds results in the fabrication of photothermal MNs with thin plasmonic layers. The photothermal performance of these MN arrays is compared to ones made by three methods utilizing NP dispersions, and it is found that similar temperatures are reached with 28-fold lower Au mass due to reduced light scattering losses of the thin layers. Finally, all developed photothermal MN arrays here cause clinically relevant hyperthermia at benign laser intensities while reducing intradermal NP deposition 127-fold compared to conventional MNs made with water-soluble polymers. Such rational design of photothermal MNs requiring low laser intensities and minimal NP intradermal accumulation sets the basis for their safe clinical translation.

The instability of the molecular electrodes under oxidative/reductive conditions and insufficient understanding of the metal oxide-based systems have slowed down the progress of H2-based fuels. Efficient regeneration of the electrode’s performance after prolonged use is another unavoidable bottle-neck of this research. This study presents the development of an efficient, and reusable electrode suitable for use as both anode and cathode in electrochemical cells for H2 production. Pyridyl units with flexible arms (-CH2-CH2-) were used to anchor a highly active ruthenium electrocatalyst [RuII(mcbp)(H2O)2] (1) [mcbp2− = 2,6-bis(1-methyl-4-(carboxylate)benzimidazol-2-yl)pyridine] onto fluorine-doped carbon cloth. This resulted in RuPFCC, a high-performing electrode for oxygen evolution [OE, overpotential of ̴ 215 mV] as well as hydrogen evolution reaction (HER, overpotential of ̴ 330 mV) at pH 7. Current density of ̴ 8 mA/cm2 at 1.65 V (vs NHE) and ̴ -6 mA/cm2 at -1.25 V (vs NHE) with only 0.04 w% loading of ruthenium was obtained. OER turnover of > 7.4 × 103 at 1.4 V in 48 h and HER turnover of > 3.6 × 103 at -1.2 V in 3 h were calculated. The activity of the OE anode after 48 h use could be electrochemically regenerated to ̴ 98% of its original activity while using it as a HE cathode (i.e., while evolving hydrogen) for 6 h. This work provides efficient strategies for developing ultra-stable molecular electrodes with exciting electrochemical regeneration, that can be used in electrochemical cells.

AbstractSurface‐enhanced Raman scattering (SERS) is a powerful sensing technique. However, the employment of SERS sensors in practical applications is hindered by high fabrication costs from processes with limited scalability, poor batch‐to‐batch reproducibility, substrate stability, and uniformity. Here, highly scalable and reproducible flame aerosol technology is employed to rapidly self‐assemble uniform SERS sensing films. Plasmonic Ag nanoparticles are deposited on substrates as nanoaggregates with fine control of their interparticle distance. The interparticle distance is tuned by adding a dielectric spacer during nanoparticle synthesis that separates the individual Ag nanoparticles within each nanoaggregate. The dielectric spacer thickness dictates the plasmonic coupling extinction of the deposited nanoaggregates and finely tunes the Raman hotspots. By systematically studying the optical and morphological properties of the developed SERS surfaces, structure–performance relationships are established and the optimal hot‐spots occur for interparticle distance of 1 to 1.5 nm among the individual Ag nanoparticles, as also validated by computational modeling, are identified for the highest signal enhancement of a molecular Raman reporter. Finally, the superior stability and batch‐to‐batch reproducibility of the developed SERS sensors are demonstrated and their potential with a proof‐of‐concept practical application in food‐safety diagnostics for pesticide detection on fruit surfaces is explored.

Co-free Li-rich layered oxides are gaining interest as feasible positiveelectrode materials in lithium-ion batteries (LIBs) in terms of energy density, costreduction, and alleviating safety concerns. Unfortunately, their commercialization ishindered by severe structural degradation that occurs during electrochemical operation.The study at hand demonstrates advanced structural engineering of a Li-rich Co-freeoxide with composition Li1.1Ni0.35Mn0.55O2by spray pyrolysis and subsequentcalcination of an aqueous precursor, creating a segregated structure of two distinctlayered phases with space groupsR3??m(rhombohedral) andC2/m(monoclinic). Thisparticular structure was investigated with powder neutron diffraction, high-resolutionanalytical transmission electron microscopy imaging, and electron energy loss spectroscopic characterization. This complex structurecontributes to the high electrochemical stability and good rate capability observed for this compound (160 mAh/g at C/3 and 100mAh/g at 1C).These results provide new insights into the feasibility of developing and commercializing cobalt-free positiveelectrode materials for LIBs