Layered double hydroxides (LDHs) are an emergent class of biocompatible inorganic lamellar nanomaterials that have attracted significant research interest owing to their high surface-to-volume ratio, the capability to accumulate specific molecules, and the timely release to targets. Their unique properties have been employed for applications in organic catalysis, photocatalysis, sensors, drug delivery, and cell biology. Given the widespread contemporary interest in these topics, time-to-time it urges to review the recent progresses. This review aims to summarize the most recent cutting-edge reports appearing in the last years. It firstly focuses on the application of LDHs as catalysts in relevant chemical reactions and as photocatalysts for organic molecule degradation, water splitting reaction, CO₂ conversion, and reduction. Subsequently, the emerging role of these materials in biological applications is discussed, specifically focusing on their use as biosensors, DNA, RNA, and drug delivery, finally elucidating their suitability as contrast agents and for cellular differentiation. Concluding remarks and future prospects deal with future applications of LDHs, encouraging researches in better understanding the fundamental mechanisms involved in catalytic and photocatalytic processes, and the molecular pathways that are activated by the interaction of LDHs with cells in terms of both uptake mechanisms and nanotoxicology effects.

We performed in situ angle-resolved photoemission spectroscopy measurements on ${\text{La}}_{2/3}{\text{Sr}}_{1/3}{\text{MnO}}_3$ thin and ultrathin films deposited onto ${\text{SrTiO}}_3$ substrates in order to determine their electronic band structure. We directly identified, in ultrathin films, an enhancement of the occupation of the out-of-plane $\text{Mn}3d{e}_g$ $\left(3z^2-r^2\right)$ band at the expense of the in-plane $3d{e}_g$ $\left(x^2-y^2\right)$ band. Such a disproportionate change in orbital occupation is interpreted as the origin of the strong depression of the magnetotransport properties at the interface between manganite films and substrates.

Two types of (Zn, Al) layered double hydroxide were prepared by a hydrothermal process at room temperature using Zn salt precursors on Al foils. The examined LDHs differ for the hosted anions in the interlamellar space, namely Cl ⁻ and NO ₃ ⁻ . Scanning electron microscopy, X‐ray photoelectron spectroscopy and ultraviolet photoemission spectroscopy have been used to characterize four types of the samples, representative of the two hosted anions (Cl ⁻ and NO ₃ ⁻ ) and two times of growth (6 and 24 h). X‐ray photoelectron spectroscopy results permitted to describe the interactions between inorganic anions hosted in the interlamellar space and the metallic cations on the brucite layer. They also allowed giving a tentative explanation of the different morphologies observed by scanning electron microscopy. Copyright © 2016 The Authors Surface and Interface Analysis Published by John Wiley & Sons Ltd.

Resonant sensors with nanostructured surfaces have long been considered as an emergent platform for high-sensitivity transduction because of the potentially very large sensing areas. Nevertheless, until now only complex, time-consuming, expensive and sub-optimal fabrication procedures have been described; in fact, especially with reference to in-liquid applications, very few devices have been reported. Here, we first demonstrate that, by immersing standard, ultra-low-cost quartz resonators with un-polished silver electrodes in a conventional zinc nitrate/HMTA equimolar nutrient solution, the gentle contamination from the metallic package allows direct growth on the electrodes of arrays of high-density (up to 10 μm−2) and well-separated (no fusion at the roots) ZnO nanowires without any seed layer or thermal annealing. The combination of high-density and good separation is ideal for increasing the sensing area; moreover, this uniquely simple, single-step process is suitable for conventional, ultra-low-cost and high-frequency quartzes, and results in devices that are already packaged and ready to use. As an additional advantage, the process parameters can be effectively optimized by measuring the quartz admittance before and after growth. As a preliminary test, we show that the sensitivity to the liquid properties of high-frequency (i.e. high sensitivity) quartzes can be further increased by nearly one order of magnitude and thus show the highest ever reported frequency shifts of an admittance resonance in response to immersion in both ethanol and water.