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 μg/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.

Due to their high potential energy storage, magnetite (Fe₃O₄) nanoparticles have become appealing as anode materials in lithium-ion batteries. However, the details of the lithiation process are still not completely understood. Here, we investigate chemical lithiation in 70 nm cubic-shaped magnetite nanoparticles with varying degrees of lithiation, x = 0, 0.5, 1, and 1.5. The induced changes in the structural and magnetic properties were investigated 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 concentration (x_c), which is determined to be between 0.5< x_c ≤ 1 for Fe_3−δO₄. Diffraction and magnetization measurements clearly show the formation of the antiferromagnetic LiFeO₂ phase. Upon lithiation, magnetization measurements reveal an 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 distributions involved in the lithiation process. Correlating magnetic and structural properties opens the path to increasing the understanding of the processes involved in a variety of nonmagnetic applications of magnetic materials.

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.

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) Mn_0.25Fe_2.75O₄ 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 Mn_0.25Fe_2.75O₄ 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.

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 Li_1.26Ni_0.15Mn_0.61O₂ as a lithium-rich, cobalt-free layered oxide. Al doping suppresses voltage fade and improves the capacity retention from 46% for Li_1.26Ni_0.15Mn_0.61O₂ to 67% for Li_1.26Ni_0.15Mn_0.56Al_0.05O₂ 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 (Li_1.26Ni_0.15Mn_0.61-xAl_xO₂) 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.

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.

The instability of 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 bottleneck of this research. This work represents the first example of a bifunctional and electrochemically regenerable molecular electrode which can be used for the unperturbed production of H₂ from water. Pyridyl linkers with flexible arms (–CH₂–CH₂–) on modified fluorine-doped carbon cloth (FCC) were used to anchor a highly active ruthenium electrocatalyst [Ru^II(mcbp)(H₂O)₂] (1) [mcbp²⁻ = 2,6-bis(1-methyl-4-(carboxylate)benzimidazol-2-yl)pyridine]. The pyridine unit of the linker replaces one of the water molecules of 1, which resulted in RuPFCC (ruthenium electrocatalyst anchored on –CH₂–CH₂–pyridine modified FCC), a high-performing electrode for oxygen evolution reaction [OER, overpotential of ∼215 mV] as well as hydrogen evolution reaction (HER, overpotential of ∼330 mV) at pH 7. A current density of ∼8 mA cm⁻² at 2.06 V (vs. RHE) and ∼−6 mA cm⁻² at −0.84 V (vs. RHE) with only 0.04 wt% loading of ruthenium was obtained. OER turnover of >7.4 × 10³ at 1.81 V in 48 h and HER turnover of >3.6 × 10³ at −0.79 V in 3 h were calculated. The activity of the OER anode after 48 h use could be electrochemically regenerated to ∼98% of its original activity while it serves as a HE cathode (evolving hydrogen) for 8 h. This electrode design can also be used for developing ultra-stable molecular electrodes with exciting electrochemical regeneration features, for other proton-dependent electrochemical processes.

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, large-scale, and highly reproducible nanofabrication route for SERS nano-sensors, based on the thermophoresis-assisted 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.

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).

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_1.1Ni_0.35Mn_0.54Al_0.01O₂ 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.