Francesco Scattarella

We describe a state-of-the-art X-ray scattering laboratory, within the Research Infrastructure ITACA.SB (Potentiating the Italian Capacity for Structural Biology Services in Instruct-ERIC), designed for multi-scale structural characterization of biological specimens and advanced materials with small- and wide-angle X-ray scattering (SAXS/WAXS) techniques: WAXS to probe atomic and molecular organization, and SAXS to characterize morphological and structural features at the nanoscale. The system enables (i) the concurrent acquisition of SAXS/WAXS data, (ii) the execution of scanning SAXS/WAXS microscopy, and (iii) the collection of ultra-small-angle X-ray scattering, batch BioSAXS and size-exclusion chromatography SAXS data. To demonstrate the system's versatility, we investigated the hierarchical complexity of both biological specimens and synthetic/natural fibers. We also report on analysis of well known proteins and micelles.

Bioinspired silica deposition with biomolecular templates offers a sustainable route to producing advanced inorganic materials. The templating agent is usually a polycation. Recent experimental evidence links the templating capability of polycationic polymers to self‐assembly, coacervation, or liquid–liquid phase separation processes that precede silica deposition. However, when a polycationic protein is used, there is no evidence of liquid–liquid phase separation and the behavior of folded proteins during the hydrolysis of silicon alkoxides (TMOS/TEOS) remains poorly understood. In this study, we investigate the stability and dispersity of lysozyme in the presence of the alkoxide hydrolysis byproducts (methanol and ethanol) and a nonreactive tetrahedral mimic of orthosilicic acid (pentaerythritol). Using Small‐Angle X‐ray Scattering (SAXS) and Nuclear Magnetic Resonance (NMR) spectroscopy, we demonstrate that lysozyme retains its fold and monomeric state in the presence of these species, with no evidence of aggregation or unfolding. Furthermore, we show that unlike disordered peptides, lysozyme does not require anions for structural organization, even if some self‐interaction in the presence of phosphate or other anions is found to occur. These findings support the previously proposed mechanistic model in which the folded protein provides a robust, preorganized electrostatic scaffold for silica deposition, independent of solvent‐induced phase transitions.

We propose a Shannon sampling based approach for the analysis of laboratory and synchrotron small-angle X-ray scattering (SAXS) data. This method avoids calculation of the pair distance distribution function P ( r ), which is typically used as an alternative to the model-dependent fitting of SAXS data for determining the size and shape of the scattering object. Using this new approach it is also possible to skip any model-dependent fit of the SAXS data. The method has been tested on SAXS data collected from Polysorbate 20, D-α-tocopheryl polyethylene glycol 1000 succinate spheroidal core–shell micelles and relevant well known proteins (lysozyme, apoferritin, carbonic anhydrase 2) of different molecular weights. The results confirm the potential of the approach, even for laboratory scattering data and in the presence of polydispersity. The method allows the reliable derivation of maximum size, mass, volume, polar/equatorial asymmetry, hydration fraction, shell thickness and core/shell electron-density differences for core–shell structures, directly in the q domain, working on SAXS data measured from dilute samples for which interparticle structure factors are negligible.

Disorder is an intrinsic feature of all solids, from crystals of atoms to superlattices of colloidal nanoparticles. Unlike atomic crystals, in nanocrystal superlattices, a single misplaced particle can affect the positions of neighbors over long distances, leading to cumulative disorder. This elusive form of collective particle displacement leaves clear signatures in diffraction, but little is known about how it accumulates and propagates throughout the superlattice. Here we rationalize the propagation and accumulation of disorder in a series of CsPbBr₃ nanocrystal superlattices by using synchrotron grazing incidence small- and wide-angle X-ray scattering. CsPbBr₃ nanocrystals of colloidal softness S in the range of 0.3-0.7 were obtained by preparing particles with different sizes and ligand mixtures consisting of oleic acid and primary amines of variable lengths. Most diffraction patterns showed clear signatures of anisotropic disorder, with multilayer diffraction characteristics of high structural coherence visible only for the {100} axial directions and lost in all other directions. As the softness decreased, the superlattices transitioned to a more ordered regime where small-angle diffraction peaks became resolution-limited, and superlattice multilayer diffraction appeared for the (110) diagonal reflections. To rationalize these anisotropies in structural coherence and their dependence on superlattice softness, we propose a sinusoidal displacement model where longitudinal and transverse displacements modulate nanocrystal positions. The model explains experimental observations and advances the understanding of disorder in mesocrystalline systems as they approach the limits of structural perfection.

The controlled assembly of nanocrystals (NCs) in 3D systems is an intriguing strategy to engineer innovative materials with advanced functionalities. Herein, undoped and manganese‐doped cesium lead mixed halide perovskite NCs are organized into ordered superstructures. The synthesis of CsPbCl _x Br _3–x NCs is carried out under mild conditions, achieving nanocubes with tunable composition emission and high quantum yields. Incorporating Mn(II) as a dopant induces the appearance of a red emission band and introduces a morphological diversity at the nanoscale. Well‐faceted micrometer‐sized supercrystals (SCs) on substrates without external templates are fabricated by a slow destabilization approach, based on capillary‐driven assembly in an antisolvent vapor environment. Through comprehensive structural and spectroscopic characterization, remarkable differences between doped and undoped systems are reveled in terms of their assembly behavior, morphology, and optical properties. Confocal microscopy, combined with fluorescence lifetime imaging microscopy, uncovers the unexpected spatial arrangement of emission within these superstructures, while diffraction analysis identifies distinct domains in co‐crystallized supercuboids. These findings provide crucial insights into how dopant incorporation influences the assembly processes and the collective optical behavior in perovskite SCs, establishing a foundation for designing functional NC architectures with tailored properties for next‐generation optoelectronic applications.

SUNBIM (supramolecular and submolecular nano- and biomaterials X-ray imaging) is a computer suite of integrated programs which, through a user-friendly graphical interface, is able to perform a number of functions for (grazing-incidence) small- and wide-angle X-ray scattering [(GI)SAXS and (GI)WAXS] data analysis. The software combines in the same package both originally developed algorithms and reliable methods documented in the literature. Recently, new tools have been added to the original program that are particularly devoted to data reduction. The release presented in this work, named SUNBIM 4.0, features a new interface to perform deeper data reduction for multi-scan SAXS/WAXS, including dark-current subtraction, background evaluation and subtraction, and normalization of scattering intensity against local sample thickness derived from absorption contrast maps. In SUNBIM 4.0, these functionalities have been made accessible for data sets in .edf, a data format commonly used by many next-generation X-ray detectors, thanks to a new guided procedure for converting entire multi-scan data sets into a format readable by the software. A new functionality in the single data analysis section has been implemented, consisting of a semi-automatic background subtraction from the 1D profile of the azimuthal integration, corrected for a flat-panel detector geometry, to enhance peak visibility at large scattering angles (WAXS/GIWAXS). This new SUNBIM release will include a Microsoft Windows installer, as in the previous version, and will also be available for Mac OSX. We are confident that the new features will enable a more accurate and comprehensive analysis of (GI)SAXS/(GI)WAXS data, addressing the issues and limitations of the previous release while also enhancing the extraction of structural information contained within the data.

The structure of whey protein concentrate-based films was altered by interactions among components and nanoreinforcement geometry. Structural changes influenced the films' physical properties, with nanotubes being the most effective reinforcement.

In this work, regenerated cellulose textile fibers, Ioncell-F, dry-wet spun with different draw ratios, have been investigated by scanning wide-angle X-ray scattering (WAXS) using a mesoscopic X-ray beam. The fibers were found to be homogeneous on the 500 nm length scale. Analysis of the azimuthal angular dependence of a crystalline Bragg spot intensity revealed a radial dependence of the degree of orientation of crystallites that was found to increase with the distance from the center of the fiber. We attribute this to radial velocity gradients during the extrusion of the spin dope and the early stage of drawing. On the other hand, the fiber crystallinity was found to be essentially homogeneous over the fiber cross section.

We will show that photon correlations can be employed to overcome the typical limitations of conventional plenoptic imaging devices, thus leading to quantum-enhanced plenoptic imaging. In particular, we will show an unprecedented combination of resolution and depth of field combined with refocusing capability and depth extension. We will show experimental results obtained in different application scenarios, ranging from microscopy to photography-like protocols. Significant advances in acquisition speed will also be discussed, as achieved by both hardware (e.g., use of SPAD arrays, as opposed to common CMOS and CCD cameras) and software (e.g., compressive sensing, quantum tomography) solutions.

Correlation plenoptic imaging (CPI) is an optical imaging technique based on intensity correlation measurement, which enables detecting, within fundamental physical limits, both the spatial distribution and the direction of light in a scene. This provides the possibility to perform tasks such as three-dimensional reconstruction and refocusing of different planes. Compared with standard plenoptic imaging devices, based on direct intensity measurement, CPI overcomes the problem of the strong trade-off between spatial and directional resolution. Here, we study the resolution limit in a recent development of the technique, called correlation plenoptic imaging between arbitrary planes (CPI-AP). The analysis, based on Gaussian test objects, highlights the main properties of the technique, as compared with standard imaging, and provides an analytical guideline to identify the limits at which an object can be considered resolved.