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Layered (2D) perovskites are an emerging attractive 2D system with enhanced stability to ambient conditions as opposed to their highly unstable three dimensional bulk counterpart. Their uniquely tuneable optical and electrical properties are underpinning a surge of interest in 2D‐photovoltaics. So far, the development of nano‐scale integrated opto‐electronic 2D perovskite devices remains nearly unexplored since they have generally been found to be incompatible with standard top‐down semiconductor nano‐fabrication technologies. Here, following the synthesis of solvent‐stable 2D‐fluorinated phenethylammonium lead iodide perovskite (F‐PEA)2PbI4 (F‐PEAI), planar photodetectors entirely fabricated in atmosphere is demonstrated, exhibiting figures of merit rivalling those of commercial silicon photodiodes. A record large room temperature detectivity (>5 × 1017 Jones), a fast time photoresponse (rise time 1.5 ns), an extraordinarily large linear dynamic range (228 dB), as well as a photo‐responsivity of ≈ 1100 AW−1 are demonstrated for devices on a range of substrates including flexible wearable media without the need for any planarization or any atomically thin dielectric, in stark contrast to other 2D semiconductors. Finally, the suitability of nano‐scale 2D F‐PEAI photodetector arrays with sub‐wavelength pixel size of just 100 nm of use for high definition imaging is demonstrated. [ABSTRACT FROM AUTHOR]

In this work, we present three donor–acceptor thermally activated delayed fluorescence (TADF) molecules comprising a 2,3,5,6-tetrafluorobenzonitrile acceptor with various electron donor units: phenoxazine (Phx-BzN), phenothiazine (Pht-BzN), and carbazole (Cz-BzN). These molecules have been studied using steady-state and time-resolved photophysical techniques in solution, film in polymer host and in crystal state. While Cz-BzN displays TADF in solution and polymethyl methacrylate (PMMA) films, Phx-BzN and Pht-BzN are non-emissive in solution and somewhat emissive in polymer films. More interestingly, while Pht-BzN remains virtually non-emissive in all studied solvents, it exhibits strong photoluminescence and TADF in crystal state, attributed to Crystallization Induced Emission (CIE). Interestingly, by applying ultrasound to an amorphous Pht-BzN water suspension we were also able to induce a reorganization of the molecules obtaining a microcrystal suspension. This can represents a new strategy to develop luminescent organic microcrystalline materials. We demonstrate through computational studies that the CIE properties arise due to intermolecular interactions in the crystal structure that result in locking the ground state molecular geometry and blocking relaxation in the excited state. As a result, the oscillator strength in the crystal form is enhanced leading to a highly luminescent behaviour, while in solution it equals nearly zero due to the molecule adopting a perfectly orthogonal D–A orientation in the excited state. [ABSTRACT FROM AUTHOR]

Chitin, a ubiquitous biopolymer, holds paramount scientific and economic significance. Historically, it has been primarily isolated from marine crustaceans. However, the surge in demand for chitin and the burgeoning interest in biopolymers have necessitated the exploration of alternative sources. Among these methods, the mulberry silkworm (Bombyx mori) has emerged as a particularly intriguing prospect. To isolate chitin from Bombyx mori, a chemical extraction methodology was employed. This process involved a series of meticulously orchestrated steps, including Folch extraction, demineralization, deproteinization, and decolorization. The resultant chitin was subjected to comprehensive analysis utilizing techniques such as attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR), 13C nuclear magnetic resonance (NMR) spectroscopy, and wide-angle X-ray scattering (WAXS). The obtained results allow us to conclude that the Bombyx mori represents an attractive alternative source of α-chitin. [ABSTRACT FROM AUTHOR]

We introduce an innovative theoretical framework tailored for the analysis of Pair Distribution Function (PDF) data derived from Small-Angle X-ray Scattering (SAXS) measurements of core-shell micelles. The new approach involves the exploitation of the first derivative of the PDF and the derivation of analytical equations to solve the core-shell micelle structure under the hypothesis of a spheroidal shape. These analytical equations enable us to determine the micelle's aggregation number, degree of ellipticity, and contrast in electron density between the core-shell and shell-buffer regions after having determined the whole micelle size and its shell size from the analysis of the first derivative of the PDF. We have formulated an overdetermined system of analytical equations based on the unknowns that characterize the micelle structure. This allows us to establish a Figure of Merit, which is utilized to identify the most reliable solution within the system of equations. [ABSTRACT FROM AUTHOR]

Acrylonitrile‐butadiene‐styrene (ABS) based composites with a high content of tungsten and bismuth oxide were developed using an innovative process to obtain lead‐free x‐ray shielding materials. ABS was chosen for its good mechanical properties and its widespread availability as a recycled material. The composites underwent flexural tests, Shore D hardness tests, thermogravimetric and morphological analysis, and their x‐ray attenuation properties were determined through numerical simulations and experimental measurements. Despite their high filler content (up to 75 wt%), the composites showed good filler dispersion within the polymeric matrix and maintained their mechanical properties. Across the investigated energy range (50–150 kV), the lead equivalence for x‐ray shielding was achieved with composite plates containing 75 wt% of tungsten and bismuth oxide, at thickness values corresponding to a weight increase of only 29% and 36%, respectively, in comparison to lead. These findings pave the way for a new generation of lead‐free x‐ray shielding materials. Moreover, their mechanical properties, including flexibility for potential application in wearable personal protective equipment, can be tailored by adjusting the filler content. Highlights: High filler content lead‐free ABS composites with WO3 and Bi2O3 were developed.They show good polymer/filler interfacial adhesion and flexural properties.Numerical simulations of their x‐ray shielding properties were performed.Experimental tests with polychromatic sources confirmed good x‐ray attenuation.Results pave the way for the development of new lead‐free x‐ray shielding systems. [ABSTRACT FROM AUTHOR]

Flexible perovskite solar cells are lightweight, bendable, and applicable to curved surfaces. Polyethylene terephthalate (PET) has become the substrate of choice compared to other plastic substrates like polyethylene naphthalate. PET is not only stable but also much cheaper to manufacture, an important factor for photovoltaics (PV). Herein, highly efficient devices on PET are demonstrated using a dual low‐temperature (≤100 °C) approach, first by anion mixing (replacing I with Br) of the lead‐containing perovskite composition, increasing bandgap (42% improvement), and then by interfacial engineering with tetrabutylammonium bromide (TBAB) (a further 26% improvement), reaching efficiencies of 28.9% at 200 lx and a record 32.5% at 1000 lx. The TBA+ cation intercalates into the structure, substituting formamidinium cations at the perovskite/TBAB interface, inducing the formation of large‐sized, lower dimensional structures over the 3D perovskite matrix. The resulting PV cell has 1.4 times higher carrier lifetime, one order of magnitude lower leakage currents, and 3 times lower defect densities, suppressing recombination. Importantly, stability (ISOS‐D1 protocol) improves by more than double with treatment. Highly efficient and stable cells on PET films enable seamless integration with wearable, portable, smart building, and Internet of Things electronic devices, expanding the reach of indoor applications. [ABSTRACT FROM AUTHOR]

Type I collagen physiological scaffold for tissue regeneration is considered one of the widely used biomaterials for tissue engineering and medical applications. It is hierarchically organized: five laterally staggered molecules are packed within fibrils, arranged into fascicles and bundles. The structural organization is correlated to the direction and intensity of the forces which can be loaded onto the tissue. For a tissue-specific regeneration, the required macro- and microstructure of a suitable biomaterial has been largely investigated. Conversely, the function of multiscale structural integrity has been much less explored but is crucial for scaffold design and application. In this work, collagen was extracted from different animal sources with protocols that alter its structure. Collagen of tendon shreds excised from cattle, horse, sheep and pig was structurally investigated by wide- and small-angle X-ray scattering techniques, at both molecular and supramolecular scales, and thermo-mechanically with thermal and load-bearing tests. Tendons were selected because of their resistance to chemical degradation and mechanical stresses. The multiscale structural integrity of tendons' collagen was studied in relation to the animal source, anatomic location and source for collagen extraction. [ABSTRACT FROM AUTHOR]

High-dimensionality Ruddlesden-Popper (RP) perovskites, with general formula R2An-1BnX3nþ1 and high n values (n =5), are regarded as viable materials for photovoltaics because they feature higher stability if compared to the 3D perovskite, i.e., ABX3, still maintaining good charge absorption and transport properties. When integrated into the actual solar cells, however, scattered, sometimes contradictory results are reported among different deposition procedures and different cations, especially for higher n resulting in not uniformmorphology and mixed composition. Herein, high-dimensionality RP perovskites with n = 1, 4, 10, 20, and 40 values are systematically investigated considering the interplay between the formation of 2D domains, their distribution along the active layer, the active layer thickness, and the solar cells' performance. Given the complexity of the investigated system, combined advanced structural/morphological analyses are performed to explain solar cells' performance, finding that the 2D phase segregates at the interface with the top electrode, acting as a barrier for charge extraction, overall decreasing the shortcircuit current (Jsc). Reducing the relative amount of bulky alkylammonium cation with respect to the methylammonium, the 2D perovskite overlayer is intentionally decreased leading to a recovery of the Jsc values, corroborating the hypothesis. [ABSTRACT FROM AUTHOR]

In the last two decades, fisheries and fish industries by-products have started to be recovered for the extraction of type I collagen because of issues related to the extraction of traditional mammalian tissues. In this work, special attention has been paid to by-products from fish bred in aquaponic plants. The valorization of aquaponic fish wastes as sources of biopolymers would make the derived materials eco-friendlier and attractive in terms of profitability and cost effectiveness. Among fish species, Nile Tilapia is the second-most farmed species in the world and its skin is commonly chosen as a collagen extraction source. However, to the best of our knowledge, no studies have been carried out to investigate, in depth, the age-related differences in fish skin with the final aim of selecting the most advantageous fish size for collagen extraction. In this work, the impact of age on the structural and compositional properties of Tilapia skin was evaluated with the aim of selecting the condition that best lends itself to the extraction of type I collagen for biomedical applications, based on the known fact that the properties of the original tissue have a significant impact on those of the final product. Performed analysis showed statistically significant age-related differences. In particular, an increase in skin thickness (+110 µm) and of wavy-like collagen fiber bundle diameter (+3 µm) besides their organization variation was observed with age. Additionally, a preferred collagen molecule orientation along two specific directions was revealed, with a higher fiber orientation degree according to age. Thermal analysis registered a shift of the endothermic peak (+1.7 °C) and an increase in the enthalpy (+3.3 J/g), while mechanical properties were found to be anisotropic, with an age-dependent brittle behavior. Water (+13%) and ash (+0.6%) contents were found to be directly proportional with age, as opposed to protein (−8%) and lipid (−10%) contents. The amino acid composition revealed a decrease in the valine, leucine, isoleucine, and threonine content and an increase in proline and hydroxyproline. Lastly, fatty acids C14:0, C15:0, C16:1, C18:2n6c, C18:3n6, C18:0, C20:3n3, and C23:0 were revealed to be upregulated, while C18:1n9c was downregulated with age. [ABSTRACT FROM AUTHOR]

In this work we have studied in situ the formation and growth of calcium phosphate (CaP) nanoparticles (NPs) in the presence of three calcium-binding carboxylate molecules having different affinities for Ca2+ ions: citrate (Cit), hydroxycitrate (CitOH), and glutarate (Glr). The formation of CaP NPs at several reaction temperatures ranging from 25 °C to 80 °C was monitored in situ through simultaneous Small and Wide X-ray Scattering (SAXS/WAXS) using synchrotron light. SAXS was used to investigate the first stages of NP formation where a crystalline order is not yet formed. In this regard we have developed a new bivariate mesh data analysis method for identifying the SAXS curves associated with the most relevant timeframes for performing curve modeling. WAXS was used to study the formation of crystalline phases and their evolution over time. The combined SAXS/WAXS data allowed us to track NP nucleation, their size and morphology, and their evolution up to mature hydroxyapatite (HA) nanocrystals. We have assessed that in the first stages of reaction (80 seconds) amorphous, elongated primary NPs nucleate whose size and morphology depend on the temperature and type of carboxylate molecule. The temperature controls the release of Ca2+ ions from carboxylate molecules, and thus induces the formation of a higher amount of amorphous particles and increases their size and aspect ratio. As the reaction time progresses, amorphous particles evolve into crystalline ones, whose kinetics of crystal growth are controlled by temperature and carboxylate ions. Stronger Ca-binding carboxylates (CitOH > Cit > Glr) have a more pronounced inhibiting effect on HA crystallization, retarding the formation and growth of crystalline domains, while a rise of temperature promotes crystallization. This work allowed us to shed more light on the formation of HA in the presence of growth-controlling molecules, as well as present the potential of combined SAXS/WAXS for studying the formation of highly relevant NPs for different applications. [ABSTRACT FROM AUTHOR]

Generated by a hierarchical and multiscale self-assembling phenomenon, peptide-based hydrogels (HGs) are soft materials useful for a variety of applications. Short and ultra-short peptides are intriguing building blocks for hydrogel fabrication. These matrices can also be obtained by mixing low-molecular-weight peptides with other chemical entities (e.g., polymers, other peptides). The combination of two or more constituents opens the door to the development of hybrid systems with tunable mechanical properties and unexpected biofunctionalities or morphologies. For this scope, the formulation, the multiscale analysis, and the supramolecular characterization of novel hybrid peptide-polymer hydrogels are herein described. The proposed matrices contain the Fmoc-FF (Nα-fluorenylmethyloxycarbonyl diphenylalanine) hydrogelator at a concentration of 0.5 wt% (5.0 mg/mL) and a diacrylate α-/ω-substituted polyethylene-glycol derivative (PEGDA). Two PEGDA derivatives, PEGDA 1 and PEGDA2 (mean molecular weights of 575 and 250 Da, respectively), are mixed with Fmoc-FF at different ratios (Fmoc-FF/PEGDA at 1/1, 1/2, 1/5, 1/10 mol/mol). All the multicomponent hybrid peptide-polymer hydrogels are scrutinized with a large panel of analytical techniques (including proton relaxometry, FTIR, WAXS, rheometry, and scanning electronic microscopy). The matrices were found to be able to generate mechanical responses in the 2–8 kPa range, producing a panel of tunable materials with the same chemical composition. The release of a model drug (Naphthol Yellow S) is reported too. The tunable features, the different topologies, and the versatility of the proposed materials open the door to the development of tools for different applicative areas, including diagnostics, liquid biopsies and responsive materials. The incorporation of a diacrylate function also suggests the possible development of interpenetrating networks upon cross-linking reactions. All the collected data allow a mutual comparison between the different matrices, thus confirming the significance of the hybrid peptide/polymer-based methodology as a strategy for the design of innovative materials. [ABSTRACT FROM AUTHOR]

Colloidal chemistry grants access to a wealth of materials through simple and mild reactions. However, even few elements can combine in a variety of stoichiometries and structures, potentially resulting in impurities or even wrong products. Similar issues have been long addressed in organic chemistry by using reaction-directing groups, that are added to a substrate to promote a specific product and are later removed. Inspired by such approach, we demonstrate the use of CsPbCl3 perovskite nanocrystals to drive the phase-selective synthesis of two yet unexplored lead sulfochlorides: Pb3S2Cl2 and Pb4S3Cl2. When homogeneously nucleated in solution, lead sulfochlorides form Pb3S2Cl2 nanocrystals. Conversely, the presence of CsPbCl3 triggers the formation of Pb4S3Cl2/CsPbCl3 epitaxial heterostructures. The phase selectivity is guaranteed by the continuity of the cationic subnetwork across the interface, a condition not met in a hypothetical Pb3S2Cl2/CsPbCl3 heterostructure. The perovskite domain is then etched, delivering phase-pure Pb4S3Cl2 nanocrystals that could not be synthesized directly. Phase-selective approaches, such using reaction-directing groups, are often seen in traditional organic chemistry and catalysis. Here authors use perovskite nanocrystals as disposable templates to drive the phase-selective synthesis of two colloidal nanomaterials, the lead sulfohalides Pb3S2Cl2 and Pb4S3Cl2. [ABSTRACT FROM AUTHOR]

In 2021, Wide-angle X-ray Scattering (WAXS) was applied to a sample of the Turin Shroud as a new method for dating ancient linen threads by inspecting their structural degradation. The major result of the research was to estimate the natural aging of the linen of the Shroud, through which it was found to be compatible with the hypothesis of a 2000-year-old relic, and not a medieval fabric. The present work regards the theoretical natural aging of the linen versus different alleged historical–geographical paths of the Shroud through cities where the presence of icons of Jesus Christ is attested. The theoretical results of the natural aging of the Shroud, calculated for the year 2021, agree extremely well with the experimental results for at least one alleged path. The results also show that if the Shroud were medieval and kept in Europe for 7 centuries, natural aging that is one order of magnitude less than that measured by WAXS would have resulted. Today, the Shroud is kept in a reliquary with a controlled atmosphere, at 19~20 °C temperature, and 50% relative humidity. These values are shown to be unsuitable for maintaining the depolymerization of the cellulose at a level that is sufficiently low enough to preserve the image visible on the Shroud for a long time. [ABSTRACT FROM AUTHOR]

Colloidal chemistry grants access to a wealth of materials through simple and mild reactions. However, even few elements can combine in a variety of stoichiometries and structures, potentially resulting in impurities or even wrong products. Similar issues have been long addressed in organic chemistry by using reaction-directing groups, that are added to a substrate to promote a specific product and are later removed. Inspired by such approach, we demonstrate the use of CsPbCl3 perovskite nanocrystals to drive the phase-selective synthesis of two yet unexplored lead sulfochlorides: Pb3S2Cl2 and Pb4S3Cl2. When homogeneously nucleated in solution, lead sulfochlorides form Pb3S2Cl2 nanocrystals. Conversely, the presence of CsPbCl3 triggers the formation of Pb4S3Cl2/CsPbCl3 epitaxial heterostructures. The phase selectivity is guaranteed by the continuity of the cationic subnetwork across the interface, a condition not met in a hypothetical Pb3S2Cl2/CsPbCl3 heterostructure. The perovskite domain is then etched, delivering phase-pure Pb4S3Cl2 nanocrystals that could not be synthesized directly. Phase-selective approaches, such using reaction-directing groups, are often seen in traditional organic chemistry and catalysis. Here authors use perovskite nanocrystals as disposable templates to drive the phase-selective synthesis of two colloidal nanomaterials, the lead sulfohalides Pb3S2Cl2 and Pb4S3Cl2. [ABSTRACT FROM AUTHOR]

On a sample of the Turin Shroud (TS), we applied a new method for dating ancient linen threads by inspecting their structural degradation by means of Wide-Angle X-ray Scattering (WAXS). The X-ray dating method was applied to a sample of the TS consisting of a thread taken in proximity of the 1988/radiocarbon area (corner of the TS corresponding to the feet area of the frontal image, near the so-called Raes sample). The size of the linen sample was about 0.5 mm × 1 mm. We obtained one-dimensional integrated WAXS data profiles for the TS sample, which were fully compatible with the analogous measurements obtained on a linen sample whose dating, according to historical records, is 55–74 AD, Siege of Masada (Israel). The degree of natural aging of the cellulose that constitutes the linen of the investigated sample, obtained by X-ray analysis, showed that the TS fabric is much older than the seven centuries proposed by the 1988 radiocarbon dating. The experimental results are compatible with the hypothesis that the TS is a 2000-year-old relic, as supposed by Christian tradition, under the condition that it was kept at suitable levels of average secular temperature—20.0–22.5 °C—and correlated relative humidity—75–55%—for 13 centuries of unknown history, in addition to the seven centuries of known history in Europe. To make the present result compatible with that of the 1988 radiocarbon test, the TS should have been conserved during its hypothetical seven centuries of life at a secular room temperature very close to the maximum values registered on the earth. [ABSTRACT FROM AUTHOR]

Here we present a colloidal approach to synthesize bismuth chalcohalide nanocrystals (BiEX NCs, in which E=S, Se and X=Cl, Br, I). Our method yields orthorhombic elongated BiEX NCs, with BiSCl crystallizing in a previously unknown polymorph. The BiEX NCs display a composition‐dependent band gap spanning the visible spectral range and absorption coefficients exceeding 105 cm−1. The BiEX NCs show chemical stability at standard laboratory conditions and form colloidal inks in different solvents. These features enable the solution processing of the NCs into robust solid films yielding stable photoelectrochemical current densities under solar‐simulated irradiation. Overall, our versatile synthetic protocol may prove valuable in accessing colloidal metal chalcohalide nanomaterials at large and contributes to establish metal chalcohalides as a promising complement to metal chalcogenides and halides for applied nanotechnology. [ABSTRACT FROM AUTHOR]

Here we present a colloidal approach to synthesize bismuth chalcohalide nanocrystals (BiEX NCs, in which E=S, Se and X=Cl, Br, I). Our method yields orthorhombic elongated BiEX NCs, with BiSCl crystallizing in a previously unknown polymorph. The BiEX NCs display a composition‐dependent band gap spanning the visible spectral range and absorption coefficients exceeding 105 cm−1. The BiEX NCs show chemical stability at standard laboratory conditions and form colloidal inks in different solvents. These features enable the solution processing of the NCs into robust solid films yielding stable photoelectrochemical current densities under solar‐simulated irradiation. Overall, our versatile synthetic protocol may prove valuable in accessing colloidal metal chalcohalide nanomaterials at large and contributes to establish metal chalcohalides as a promising complement to metal chalcogenides and halides for applied nanotechnology. [ABSTRACT FROM AUTHOR]

Collagen is one of the most widely used biomaterials in health-related sectors. The industrial production of collagen mostly relies on its extraction from mammals, but several issues limited its use. In the last two decades, marine organisms attracted interest as safe, abundant, and alternative source for collagen extraction. In particular, the possibility to valorize the huge quantity of fish industry waste and byproducts as collagen source reinforced perception of fish collagen as eco-friendlier and particularly attractive in terms of profitability and cost-effectiveness. Especially fish byproducts from eco-sustainable aquaponics production allow for fish biomass with additional added value and controlled properties over time. Among fish species, Oreochromis niloticus is one of the most widely bred fish in large-scale aquaculture and aquaponics systems. In this work, type I collagen was extracted from aquaponics-raised Tilapia skin and characterized from a chemical, physical, mechanical, and biological point of view in comparison with a commercially available analog. Performed analysis confirmed that the proprietary process optimized for type I collagen extraction allowed to isolate pure native collagen and to preserve its native conformational structure. Preliminary cellular studies performed with mouse fibroblasts indicated its optimal biocompatibility. All data confirmed the eligibility of the extracted Tilapia-derived native type I collagen as a biomaterial for healthcare applications. [ABSTRACT FROM AUTHOR]

During the last decades, the demand for processes developed according to the Circular Economy Principles has increased, searching for an alternative life for wastes. For this purpose, a one-pot green approach is exploited during this work to synthesize gold nanoparticles (AuNPs) by using grape pomace waste from Vitis vinifera. A raw aqueous extract of grape seeds, skin, and stems is used for AuNPs synthesis. UV-Vis, XPS, SEM, and ATR-FTIR spectroscopies demonstrate the main role of the extract's polyphenolic components in stabilizing nanoparticles. XRD, DLS, and Zeta Potential analyses were used to characterize AuNPs. Moreover, the ionic strength, pH, and temperature role was investigated through the Surface Plasmon Resonance (SPR) band observation to assess AuNPs' stability and photostability. For foreseeing the as-synthesized AuNPs' potential use in cosmetic and biomedical fields as multifunctional platforms, their antioxidant, and skin-lightening properties were tested, together with their sunscreen ability. A preliminary in-vitro evaluation is reported about the AuNPs' cytoprotective effects against H2O2 oxidative stress-induced in normal human dermal fibroblasts. Briefly, the possibility of reusing the grape pomace waste after the AuNPs synthesis as an adsorbent for the efficient removal of emergent contaminants is preliminarily discussed in the paper, further valorizing the use of waste according to a bio circular approach. [ABSTRACT FROM AUTHOR]

Type I collagen is the main component of the extracellular matrix that acts as the physical and biochemical support of tissues. Thanks to its characteristics, collagen is widely employed as a biomaterial for implantable device fabrication and as antiaging food supplementation. Because of the BSE transmission in the 1990s, aquatic animals have become a more suitable extraction source than warm-blooded animals. Moreover, as recently demonstrated, a supplementing diet with fish collagen can increase the body's collagen biosynthesis. In this context, Tilapia feeding was supplemented with hydrolyzed collagen in order to enhance the yield of extracted collagen. Tilapia skin was investigated with wide and small angle scattering techniques, analyzing the collagen structure from the submolecular to the nanoscale and correlated with Differential Scanning Calorimetry (DSC) measurements. Our studies demonstrated that the supplementation appears to have an effect at the nanoscale in which fibrils appear more randomly oriented than in fish fed with no supplemented feed. Conversely, no effect of a collagen-rich diet was observed at the submolecular scale. [ABSTRACT FROM AUTHOR]

Recently, we have reported the preparation of a silk fibroin‐supported Palladium catalyst (Pd/SF) and its use in the Suzuki‐Miyaura cross‐coupling of aryl iodides. Since its synthetic applicability and structural features are still far from being fully explored, a deeper investigation is reported here. Pd/SF is tested as a catalyst for the Suzuki‐Miyaura and Ullmann coupling reactions of aryl chlorides, in H2O/EtOH solvent mixture under atmospheric conditions. Starting from the analysis of the products of the Pd/SF promoted Ullmann reactions of poly‐haloarenes, we can hypothesize the existence of catalytic pockets where monoatomic palladium species can form stable complexes with SF. To shed light on this hypothesis, Pd/SF is characterized by Wide‐Angle X‐ray Scattering (WAXS) analysis, which supports the supposition of catalytic pockets. Finally, using a computational model developed by Molecular Mechanic Energy Minimization we have estimated the dimension of the catalytic pocket of Pd/SF (about 15 Å), in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Peptide‐based hydrogels, originated by multiscale self‐assembling phenomenon, have been proposed as multivalent tools in different technological areas. Structural studies and molecular dynamics simulations pointed out the capability of completely aromatic peptides to gelificate if hydrophilic and hydrophobic forces are opportunely balanced. Here, the effect produced by the introduction of a Cys residue in the heteroaromatic sequence of (FY)3 and in its PEGylated variant was evaluated. The physicochemical characterization indicates that both FYFCFYF and PEG8‐FYFCFYF are able to self‐assemble in supramolecular nanostructures whose basic cross‐β motif resembles the one detected in the ancestor (FY)3 assemblies. However, gelification occurs only for FYFCFYF at a concentration of 1.5 wt%. After cross‐linking of cysteine residues, the hydrogel undergoes to an improvement of the rigidity compared to the parent (FY)3 assemblies as suggested by the storage modulus (G') that increases from 970 to 3360 Pa. The mechanical properties of FYFCFYF are compatible with its potential application in bone tissue regeneration. Moreover, the avalaibility of a Cys residue in the middle of the peptide sequence could allow the hydrogel derivatization with targeting moieties or with biologically relevant molecules. [ABSTRACT FROM AUTHOR]

Motivated by the technological relevance of tungsten oxide nanostructures as valuable materials for energy saving technology, electrochemical and electrochromic characteristics of greener processed nanostructured W18O49-based electrodes are discussed in this work. For the purpose, microwave-assisted water-dispersible W18O49 nanorods have been synthesized and processed into nanostructured electrodes. An airbrushing technique has been adopted as a cost-effective large-area scalable methodology to deposit the W18O49 nanorods onto conductive glass. This approach preserves the morphological and crystallographic habit of native nanorods and allows highly homogeneous transparent coating where good electronic coupling between nanowires is ensured by a mild thermal treatment (250 °C, 30 min). Morphological and structural characteristics of active material were investigated from the synthesis to the nanocrystal deposition process by transmission and scanning electron microscopy, x-ray diffraction, atomic force microscopy and Raman spectroscopy. The as-obtained nanostructured film exhibited good reversible electrochemical features through several intercalation–deintercalation cycles. The electrochromic properties were evaluated on the basis of spectro-electrochemical measurements and showed significant optical contrast in the near-infrared region and high coloration efficiency at 550 nm. [ABSTRACT FROM AUTHOR]

Aromatic polypeptides have recently drawn the interest of the research community for their capability to self-assemble into a variety of functional nanostructures. Due to their interesting mechanical, electrical and optical properties, these nanostructures have been proposed as innovative materials in different biomedical, biotechnological and industrial fields. Recently, several efforts have been employed in the development of these innovative materials as nanoscale fluorescence (FL) imaging probes. In this context, we describe the synthesis and the functional properties of a novel fluorescent tyrosine (Tyr, Y)-based nanospheres, obtained by heating at 200 °C a solution of the PEGylated tetra-peptide PEG6-Y4. At room temperature, this peptide self-assembles into not fluorescent low ordered water-soluble fibrillary aggregates. After heating, the aggregation of different polyphenolic species generates Y4-based nanospheres able to emit FL into blue, green and red spectral regions, both in solution and at the solid state. The aggregation features of PEG6-Y4 before and after heating were studied using a set of complementary techniques (Fluorescence, CD, FT-IR, Small and Wide-Angle X-ray Scattering and SEM). After a deep investigation of their optoelectronic properties, these nanospheres could be exploited as promising tools for precise biomedicine in advanced nanomedical technologies (local bioimaging, light diagnostics, therapy, optogenetics and health monitoring). [ABSTRACT FROM AUTHOR]

Ion migration is associated with hysteresis observed in halide perovskite-based solar cells and light-emitting diodes, however, it is crucial for their effective performance in memory devices. In the halide perovskites field, a direct link between the average/local structure and the preferred ion migration hopping pathway has yet to be established. Herein, we utilize the solvent acidolysis crystallization technique to grow various halide-deficient methylammonium copper halide crystals where perovskite-type layers are found. Through synchrotron X-ray powder diffraction (XRPD) and pair distribution function (PDF) analyses, we identify the halogen vacancy site in the copper halide octahedra, the octahedra tilting, and the thermal vibrations of the atoms around their average positions. We correlate the variations in these parameters to the hysteresis observed in the current–voltage curves and subsequently to the ON/OFF ratios of proof-of-concept memory devices fabricated using inert Pt electrodes. Furthermore, our best ON/OFF ratio of ∼10 from our Pb-free devices compares well to the results obtained from two-dimensional Pb-based devices utilizing inert electrodes. [ABSTRACT FROM AUTHOR]

Silk fibroin (SF) obtained from Bombyx mori cocoon is a very promising biopolymer. It can be processed from aqueous solutions to obtain many versatile scaffolds useful in optoelectronics, photonics, and biomedicine. Aqueous solutions are prepared by dissolving degummed fibroin with chaotropic agents and then purifying by dialysis. This work presents, for the first time, a solubilization protocol, involving CeCl3·7H2O as chaotropic salt in water and ethanol, that allows to regenerate SF under a fibrous form, unlike the standard Ajisawa's method, which uses CaCl2 and allows to obtain aqueous gels. All the experimental analyses performed (SEM, XPS, WAXS, ATR‐FTIR, NMR) suggest that the fiber recovered preserves most of the morphological and structural features of the pristine SF and is doped with Ce(III) ions, that interact mainly with the oxygen atoms of CO moieties and side‐chains of amino acids. Ce(III) doped SF could be the base for new luminescent materials. [ABSTRACT FROM AUTHOR]

This work describes the application of X‐ray ptychography for the inspection of complex assemblies of highly anisotropic nanocrystals embedded in a thick polymer matrix. More specifically, this case deals with CdSe/CdS octapods, with pod length L = 39 ± 2 nm and pod diameter D = 12 ± 2 nm, dispersed in free‐standing thick films (24 ± 4 µm) of polymethyl methacrylate and polystyrene, with different molecular weights. Ptychography is the only imaging method available to date that can be used to study architectures made by these types of nanocrystals in thick polymeric films, as any other alternative direct method, such as scanning/transmission electron microscopy, can be definitively ruled out as a result of the large thickness of the free‐standing films. The electron density maps of the investigated samples are reconstructed by combining iterative difference map algorithms and a maximum likelihood optimization algorithm. In addition, post image processing techniques are applied to both reduce noise and provide a better visualization of the material morphological details. Through this process, at a final resolution of 27 nm, the reconstructed maps allow us to visualize the intricate network of octapods inside the polymeric matrices. [ABSTRACT FROM AUTHOR]

Anthracene derivative compounds are currently investigated because of their unique physical properties (e.g. bright luminescence and emission tunability), which make them ideal candidates for advanced optoelectronic devices. Intermolecular interactions are the basis of the tunability of the optical and electronic properties of these compounds, whose prediction and exploitation benefit from knowledge of the crystal structure and the packing architecture. Polymorphism can occur due to the weak intermolecular interactions, requiring detailed structural analysis to clarify the origin of observed material property modifications. Here, two silylethyne‐substituted anthracene compounds are characterized by single‐crystal synchrotron X‐ray diffraction, identifying a new polymorph in the process. Additionally, laser confocal microscopy and fluorescence lifetime imaging microscopy confirm the results obtained by the X‐ray diffraction characterization, i.e. shifting the substituents towards the external benzene rings of the anthracene unit favours π–π interactions, impacting on both the morphology and the microscopic optical properties of the crystals. The compounds with more isolated anthracene units feature shorter lifetime and emission spectra, more similar to those of isolated molecules. The crystallographic study, supported by the optical investigation, sheds light on the influence of non‐covalent interactions on the crystal packing and luminescence properties of anthracene derivatives, providing a further step towards their efficient use as building blocks in active components of light sources and photonic networks. [ABSTRACT FROM AUTHOR]

All‐inorganic lead‐halide perovskite nanocrystals continue to attract the attention of the scientific community due to their optical potential. In this work, we demonstrate that synthetic approaches based on the modulation of the ligand‐to‐metal ratio in hot‐injection methods can provide direct access to a variety of colloidal nanocrystal morphologies without resorting to post‐synthetic transformations. The shape tailoring observed for iodine‐based perovskite nanocrystals suggests that nanowires can evolve through the oriented attachment of nanocubes in the presence of high ligand‐to‐metal ratios. Conversely, mixed‐halide perovskite nanoplatelets are generated in low‐surfactant regimes, due to the peculiar reactivity of halo‐plumbate species generated before cesium injection, which favors an anisotropic growth of the nanoparticles. These results contribute to deepen the knowledge on the shape evolution of perovskite nanoparticles, thus opening the way to the development of new synthetic approaches. [ABSTRACT FROM AUTHOR]

Studies carried out in recent decades have revealed that the ability to self‐assemble is a widespread property among biomolecules. Small nucleic acid moieties or very short peptides are able to generate intricate assemblies endowed with remarkable structural and spectroscopic properties. Herein, the structural/spectroscopic characterization of aggregates formed by nucleobases and peptide nucleic acid (PNA)–peptide conjugates are reported. At high concentration, all studied nucleobases form aggregates characterized by previously unreported fluorescence properties. The conjugation of these bases, as PNA derivatives, to the dipeptide Phe–Phe leads to the formation of novel hybrid assemblies, which are characterized by an amyloid‐like association of the monomers. Although these compounds share the same basic cross‐β motif, the nature and number of PNA units have an important impact on both the level of structural order and the intrinsic fluorescence of the self‐assembled nanostructure. [ABSTRACT FROM AUTHOR]

In situ X‐ray diffraction experiments offer a unique opportunity to investigate structural dynamics at atomic resolution, by collecting several patterns in an appropriate time sequence (data matrix) while varying the applied stimulus (e.g. temperature changes). Individual measurements can be processed independently by refinement procedures that are based on prior knowledge of the average structure of each crystal phase present in the sample. If the refinement converges, parameters of the average structural model can be assessed and studied as a function of the stimulus variations. An alternative approach consists in applying a multivariate analysis to the data matrix as a whole. Methods such as principal component analysis (PCA) and phase‐sensitive detection perform fast, blind and model‐independent calculations that can be used for on‐site analysis to identify trends in data actually related to the applied stimulus. Both classical and multivariate approaches are here applied to the in situ X‐ray diffraction pair distribution function (PDF) setup on two samples of the hybrid perovskite methylammonium (MA) lead iodide obtained by different synthetic routes, subjected to temperature variations. The PDF refinement allows assessing the occurrence of temperature‐induced rotations of the PbI6 octahedra and variations in the relative amount of MAPbI3 and intermediate PbI2–MAI–DMSO (dimethyl sulfoxide) crystal phases. A change in the orientation of the methylammonium molecule with temperature is also characterized. Results of the multivariate analysis tools, which include a newly introduced space‐dependent variant of PCA, are described, interpreted and validated against simulated data, and their specificity and relation to refinement results are highlighted. The interaction between nearby octahedra is identified as the driving force for the tetragonal‐to‐cubic phase transition, and three fundamental trends in data having different temperature behaviours are unveiled: (i) irreversible weight‐fraction variations of the MAPbI3 and PbI2–MAI–DMSO phases; (ii) reversible structural changes related to the MAPbI3 crystalline phase and its lattice distortion in the ab plane, having the same frequency as the temperature variations; (iii) reversible lattice distortion along the c axis, occurring at twice the frequency of the temperature changes. [ABSTRACT FROM AUTHOR]

Developing effective strategies to increase the chemical stability and to fine‐tune the physico‐chemical properties of melanin biopolymers by rational control of π‐electron conjugation is an important goal in materials science for biomedical and technological applications. Herein we report that poly‐1,8‐dihydroxynaphthalene (pDHN), a non‐nitrogenous, catechol‐free fungal melanin mimic, displays a high degree of structural integrity (from MALDI‐MS and CP/MAS 13C NMR analysis), a strong radical scavenging capacity (DPPH and FRAP assays), and an unusually intense EPR signal (g=2.0030). Morphological and spectral characterization of pDHN, along with deassembly experiments in ionic liquids, indicated amorphous aggregates of small globular structures with an estimated stacking distance of 3.9 Å and broadband absorption throughout the visible range. These results indicate that DHN‐based melanins exhibit a high structural integrity and enhanced antioxidant and free‐radical properties of potentially greater biomedical and technological relevance than for typical indole‐based eumelanins. [ABSTRACT FROM AUTHOR]

Nucleophosmin 1 (NPM1) is a nucleus‐cytoplasm shuttling protein ubiquitously expressed and highly conserved. It is involved in many cellular processes and its gene is mutated in ~ 50–60% of Acute Myeloid Leukemia (AML) patients. These mutations cause its cytoplasmic mislocation and accumulation (referred to as NPM1c+) and open the door to rational targeted therapy for AML diseases with mutated NPM1. Currently, there is limited knowledge on the mechanism of action of NPM1c+ and on structural determinants of the leukemogenic potential of AML mutations. Numerous previous studies outlined an unexpected amyloid‐like aggregation tendency of several regions located in the C‐terminal domain that, in wild‐type form, fold as a three‐helical‐bundle. Here, using a combination of different techniques including Thioflavin T fluorescence, congo red absorbance, CD spectroscopy, Scanning Electron Microscopy (SEM) and wide‐angle X‐ray scattering on a series of peptides bearing mutations, we evidence that the amyloidogenicity of NPM1 mutants is directly linked to AML. Noticeably, AML point mutations strongly affect the amyloid cytotoxic effects in neuroblastoma cells and the morphologies of deriving fibrils. This study paves the way to deepen our understanding of AML‐associated NPM1 mutants, and could help to break new ground for the identification of novel drugs targeting NPM1c+ for treatment of AML. [ABSTRACT FROM AUTHOR]

The surface chemistry of colloidal cesium lead bromide (CsPbBr3) nanocrystals is decisive in determining the stability and the final morphology of this class of materials, characterized by ionic structure and a high defect tolerance factor. Here, the high sensitivity of purified colloidal nanocubes of CsPbBr3 to diverse environmental condition (solvent dilution, ageing, ligands post synthetic treatment) in ambient atmosphere is investigated by means of a comprehensive morphological (electron microscopy), structural (θ/2θ X-ray diffraction (XRD) and grazing incidence wide angle scattering (GIWAXS)), and spectroscopic chemical (1H nuclear magnetic resonance (NMR), nuclear Overhauser effect spectroscopy (NOESY), absorption and emission spectroscopy) characterization. The aging and solvent dilution contribute to modify the nanocrystal morphology, due to a modification of the ligand dynamic. Moreover, we establish the ability of aliphatic carboxylic acids and alkyl amines ligands to induce, even in a post preparative process at room temperature, structural, morphological and spectroscopic variations. Upon post synthesis alkyl amine addition, in particular of oleyl amine and octyl amine, the highly green emitting CsPbBr3 nanocubes effectively turn into one-dimensional (1D) thin tetragonal nanowires or lead halide deficient rhombohedral zero-dimensional (0D) Cs4PbBr6 structures with a complete loss of fluorescence. The addition of an alkyl carboxylic acid, as oleic and nonanoic acid, produces the transformation of nanocubes into still emitting orthorombic two-dimensional (2D) nanoplates. The acid/base equilibrium between the native and added ligands, the adsorbed/free ligands dynamic in solution and the ligand solubility in non-polar solvent contribute to render CsPbBr3 particularly sensitive to environmental and processing conditions and, therefore prone to undergo to structural, morphological and, hence spectroscopic, transformations. [ABSTRACT FROM AUTHOR]