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Nanoencapsulated phase change materials (nePCMs) are nowadays under research for thermal energy storage purposes. NePCMs are composed of a phase change core surrounded by a shell that confines the core when molten. One of the main concerns of nePCMs when subjected to thermal processes is the mechanical failure of the passivation shell initially present in commercial metallic nanoparticles. In order to overcome this issue, multi-coated nePCMs, based on the synthesis of an additional coating by atomic layer deposition, appear to be as a candidate solution. With the objective of studying the influence of the composition and thickness of the additional nePCM shells on their probability of failure, a numerical tool combining a thermomechanical finite element model with phase change and Monte Carlo algorithms is developed. This tool also allows including the uncertainty of material and geometrical properties into the numerical analysis to account for their influence in the mechanical performance of nePCMs. In the present work, the mechanical reliability of SiO2 and Al2O3 coatings on Sn@SnOx nanoparticles is assessed by considering both deterministic and probabilistic failure criteria and Al2O3 coatings appear to have a better mechanical performance than their SiO2 counterparts.

Oral delivery of peptides requires formulations with high concentrations of permeation enhancer (PE) to promote absorption, and often necessitates fasting time between dosing and food ingestion. Improved formulations promoting a more rapid absorption would increase convenience of use but requires a faster onset of action. We have developed a salcaprozate-based ionic liquid (IL) formulation, namely choline salcaprozate (CHONAC), for oral delivery of a glucagon-like peptide-1 (GLP-1) analogue via gastric absorption. In vitro studies confirmed the higher amount of PE accommodated in the same volume of dosage form as well as faster release of the active pharmaceutical ingredient (API) and PE compared to the tablet reference. Storage stability of the CHONAC formulation was demonstrated for up to 3 weeks at 4 °C. The peptide absorption efficacy of the IL formulation was first evaluated in vivo in rats and anesthetized dogs, showing a faster absorption compared to the reference formulations. In awake dogs, while the CHONAC formulation still enabled earlier API absorption, its overall exposure was inferior to the tablet reference. This was attributed mostly to the gastric physiology, causing formulation dilution in the presence of additional fluid as well as fast transit of liquids into the duodenum, where peptides liable to proteolytic degradation such as the one used in this study showed a negligible absorption, potentially also due to a lower permeation-enhancing capability of CHONAC in the duodenal region. Exploring these issues, an in vivo study in anesthetized dogs involving repeated dosing of a liquid salcaprozate-based formulation in the stomach revealed the potential to sustain peptide absorption throughout the dosing period with a constant absorption rate. In conclusion, combining the advantages of high PE amounts and fast onset of action provided by the IL formulation, and ensuring a prolonged interaction of peptide and PE at a relevant concentration with the stomach epithelium, are necessary to enhance oral peptide bioavailability via gastric delivery., (Copyright © 2024. Published by Elsevier B.V.)

Understanding the spontaneous organization of atoms on well-defined surfaces promises to enable control over the shape and size of supported nanostructures. Atomic layer deposition (ALD) boasts atomic-scale control in the synthesis of thin films and nanoparticles. Yet, the possibility to control the shape of ALD-grown nanostructures remains mostly unexplored. Here, we report on the bottom-up formation of both linear and V-shaped anatase TiO 2 nanorods (NRs) on graphene nanoplatelets during TiCl 4 /H 2 O ALD carried out at 300 °C. NRs as large as 200 nm form after only five ALD cycles, indicating that diffusional processes rather than layer-by-layer growth are behind the NR formation. In particular, high-resolution transmission electron microscopy reveals that the TiO 2 NRs and graphene nanoplatelets are in rotational alignment as a result of lattice matching. Crucially, we also show that individual nanocrystals can undergo in-plane oriented attachment., Competing Interests: The authors declare no competing financial interest.

A fundamental understanding of the interplay between ligand-removal kinetics and metal aggregation during the formation of platinum nanoparticles (NPs) in atomic layer deposition of Pt on TiO 2 nanopowder using trimethyl(methylcyclo-pentadienyl)platinum(IV) as the precursor and O 2 as the coreactant is presented. The growth follows a pathway from single atoms to NPs as a function of the oxygen exposure (P O2 × time). The growth kinetics is modeled by accounting for the autocatalytic combustion of the precursor ligands via a variant of the Finke-Watzky two-step model. Even at relatively high oxygen exposures (<120 mbar s) little to no Pt is deposited after the first cycle and most of the Pt is atomically dispersed. Increasing the oxygen exposure above 120 mbar s results in a rapid increase in the Pt loading, which saturates at exposures >> 120 mbar s. The deposition of more Pt leads to the formation of NPs that can be as large as 6 nm. Crucially, high P O2 (≥5 mbar) hinders metal aggregation, thus leading to narrow particle size distributions. The results show that ALD of Pt NPs is reproducible across small and large surface areas if the precursor ligands are removed at high P O2 ., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)