Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

Abstract

Nanostructured zirconium dioxide (zirconia) films are very promising for catalysis and biotechnological applications: a precise control of the interfacial properties of the material at different length scales and, in particular, at the nanoscale, is therefore necessary. Here, we present the characterization of cluster-assembled zirconia films produced by supersonic cluster beam deposition possessing cubic structure at room temperature and controlled nanoscale morphology. We characterized the effect of thermal annealing in reducing and oxidizing conditions on the crystalline structure, grain dimensions, and topography. We highlight the mechanisms of film growth and phase transitions, which determine the observed interfacial morphological properties and their resilience against thermal treatments. Published by AIP Publishing. [http://dx

Adhesion force spectroscopy with nanostructured colloidal probes reveals nanotopography-dependent early mechanotransductive interactions at the cell membrane level

“…The surface profiles of nanostructured zirconia films are characterised by peaks and valleys (see Figure 4c), defining a complex random pattern of nanoscale features, whose dimensions and spatial distribution resemble those found in natural ECM topographies 5,6 . The specific surface area, the rms roughness, the average lateral dimensions of the largest morphological features (the correlation length ξ), as well as the interfacial porosity of the films typically increase with film thickness 59,60,89 . The interfacial open pores, delimited and defined by the surface asperities 44 , can accommodate proteins (including fibronectin) and nutrients 31,[89][90][91][92] ; asperities evolve in height, area, and surface charge density 81 .…”

“…in fibrillary collagen-dominated ECM, or instead rather disordered, as in basement membranes or brain ECM. However, on the local nanoscale level often irregularities, anisotropies and density gradients are present [1][2][3][4][5][6] .…”

“…The oxidation of the nanostructured film further proceeds upon exposure to air, up to an almost complete stoichiometry, although rich of local defects. The crystalline phase is cubic at room temperature62 .The root mean square (rms) roughness rq of the deposited film, defined as the standard deviation of surface height values, evolves with the film thickness h, according to the power law 59,60 ~ ℎ , where b = 0.35 approximately (details about the evolution of the roughness-thickness relation and on the mechanical stability of the nanostructured thin film can be found in the Supporting Information, Figures S1,2) 60,62 . Therefore, by controlling the thickness of the film deposited using a quartz microbalance placed inside the deposition chamber, it is possible to produce nanotopographical CPs with very high reproducibility.…”

Neuronal Cells Confinement by Micropatterned Cluster-Assembled Dots with Mechanotransductive Nanotopography

“…with disordered yet controlled topographical features based on the assembling of zirconia nanoparticles, produced in the gas phase and accelerated in a supersonic expansion, on flat substrates (23). This bottom-up assembling technique produces nanostructured films with a nanoscale topography accurately controlled in a reproducible manner (23), (24), (26), (27).…”

“…Primary neuronal cells can be cultured on these clusterassembled substrates where they display an accelerated maturation and build-up of a functional network of neurons and synapses (21). Furthermore, SCBD enables a facile scale-up of the surface area with a predefined reproducible nanotopography (23), (24), making this nanofabrication technique compatible with thorough molecular characterization of these cell networks, including omics approaches (20), (21), (22) and high-throughput applications (25).…”