Due to their bioinspired self-assembly and biocompatibility, protein-based aerogels have drawn growing interest in biomedical applications. With its excellent gelling and self-assembly properties, whey protein isolate (WPI) represents a promising source for the fabrication of biodegradable and homogeneous tunable aerogels. Gelation pH has a significant impact on the morphological homogeneity of protein biomaterials, which is essential for controlling tissue-implant interactions. In this study, WPI aerogels were produced without gelation-induced agents (followed by a supercritical CO2 drying process), and the effect of the gelation pH was investigated by varying its value from 2 to 11. Aerogels with a high fluid absorption capacity ( 760

The heat of water adsorption on large-pores mesoporous silica suitable for hemostatic applications has been assessed. The values were determined by means of microcalorimetry (as differential heat of adsorption, Q diff, at 318 K) and variable temperature IR (VTIR) spectroscopy through the thermodynamic analysis of spectroscopic data based on the van't Hoff equation (as standard enthalpy of adsorption, Delta H 0, in the temperature range 318-360 K). The results obtained by the two different techniques are in satisfactory agreement, leading to a value of the water heat of adsorption between 30 and 37 kJ/mol, ascribed to the interaction of water molecules with terminal silanols via one H-bond. The heat of water adsorption (below 44 kJ/mol) reveals that the surface of the large-pores mesoporous silica herein investigated may be considered mainly hydrophobic. For the first time, VTIR spectroscopy of water adsorption has been applied for the characterization of the surface hydrophilicity/hydrophobicity of a silica material.

In the original publication [...].

Among solid sorbents, silica is particularly interesting thanks to its stability and versatility. With this in mind, we developed a silica sorbent impregnated with amino groups to increase its ability to capture CO2. A commercial mesoporous silica (type SBA-15) was impregnated with a diamine (diaminohexane) by using supercritical CO2 as a green solvent. The so obtained sorbent was physico-chemically characterized and its adsorption behavior was investigated by means of volumetric isotherms at room temperature (and data were fitted by Langmuir models) and in situ Fourier Infrared Spectroscopy. The results prove that the impregnation with supercritical CO2 is effective and the resulting material is able to capture CO2. Although the CO2 capture capacity value of the impregnated material is comparable to that of the pristine one (0.89 mmol/g and 0.94 mmol/g, respectively, at 25 degrees C), the impregnated sorbent is significantly more efficient in capturing CO2 at low pressure. Chemisorption and, secondary, physisorption are observed. Both phenomena are reversible at room temperature, allowing an easy regeneration of the sorbent. The material, moreover, is stable also at higher temperature, proving to be compatible with thermal regeneration processes. Finally, Langmuir modeling indicates a dual-site behavior, with stronger adsorptions sites attributed to amines, and weaker sites attributed to silica.

Hemorrhages are still considered a common cause of death and despite the availability of different hemostatic agents it is still necessary to develop more effective hemostats for bleeding managements in emergency situations. Herein, large-pores mesoporous silica microspheres (MSM) were synthesized, and their surface was modified to enrich the hydroxyls population with the aim of achieving a material with enhanced water adsorption capacity and high hemostatic ability. The success of surface modification was investigated by Fourier Transform Infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA), which confirmed the increase in the amount of surface hydroxyl groups. A hemolysis assay as well as a clotting test were carried out to evaluate the hemocompatibility and hemostatic ability, respectively. It was found that the modified material presented the lowest hemolytic ratio and the lowest clotting time. The novelty of the paper is mainly due to the coupling of the hemostatic ability test with the adsorption microcalorimetry of water. In fact, being the water adsorption on the material surface a crucial factor in the hemostatic activity, microcalorimetry was used for the first time to study the adsorption of water and estimate its heat of adsorption. The data obtained showed that the modified MSM presents a surface able to adsorb a higher amount of water, compared to the pristine MSM, with a low molar heat of adsorption (about 35 kJ/mol), which renders the modified MSM presented in the present study an excellent candidate for producing novel hemostats.

Both cyclodextrin (CD) and porous silica possess interesting properties of adsorption and release. A silica–CD hybrid, therefore, could synergically merge the properties of the two components, giving rise to a material with appealing properties for both environmental and pharmaceutical applications. With this aim, in the present study, a first hybrid is obtained through one-pot sol–gel synthesis starting from CD and tetramethyl orthosilicate (TMOS) as a silica precursor. In particular, methyl-β-cyclodextrin (bMCD) is selected for this purpose. The obtained bMCD–silica hybrid is a dense material containing a considerable amount of bMCD (45 wt.%) in amorphous form and therefore represents a promising support. However, since a high specific surface area is desirable to increase the release/adsorption properties, an attempt is made to produce the hybrid material in the form of an aerogel. Both the synthesis of the gel and its drying in supercritical CO2 are optimized in order to reach this goal. All the obtained samples are characterized in terms of their physico-chemical properties (infra-red spectroscopy, thermogravimetry) and structure (X-ray diffraction, electron microscopy) in order to investigate their composition and the interaction between the organic component (bMCD) and the inorganic one (silica).

Chronic wounds represent silent epidemic affecting a large portion of the world population, especially the elders; in this context, the development of advanced bioactive dressings is imperative to accelerate wound healing process, while contrasting or preventing infections. The aim of the present work was to provide a deep characterization of the functional and biopharmaceutical properties of a sustainable thin and flexible films, composed of whey proteins alone (WPI) and added with nanostructured zinc oxide (WPZ) and intended for the management of chronic wounds. The potential of whey proteins-based films as wound dressings has been confirmed by their wettability, hydration properties, elastic behavior upon hydration, biodegradation propensity and, when added with nanostructured zinc oxide, antibacterial efficacy against both Gram-positive and Gram-negative pathogens, i.e. Staphylococcus aureus and Escherichia coli. In-vitro experiments, performed on normal human dermal fibroblasts, confirmed film cytocompatibility, also revealing the possible role of Zn2+ ions in promoting fibroblast proliferation. Finally, in-vivo studies on rat model confirmed film suitability to act as wound dressing, since able to ensure a regular healing process while providing effective protection from infections. In particular, both films WPI and WPZ are responsible for the formation in the wound bed of a continuous collagen layer similar to that of healthy skin.

Vitamin D (VD) suffers from low water solubility and strong degradation, which both decrease its bioavailability. This work aims at obtaining a silica-surfactant-VD hybrid material and verifying if this system can protect VD from degradation and enhance its solubility. This preliminary study aspires at tuning the mesostructure order of the hybrid system (by modifying the surfactant amount) with the scope of controlling, somewhat, its drug release capability. To this purpose, two silica-surfactant-VD systems with different long-range order were synthesized and characterized in terms of physico-chemical properties and release behavior in a model solution mimicking the topical environment. Results show that the hybrid materials are able to incorporate VD, protect it from degradation up to 17 months and release it in aqueous media. The mesostructure order and the interaction between VD, surfactant and silica seem to play a key role in tuning kinetics and the amount of released drug. While the less ordered structure incorporates less VD with faster and higher release percentage, the more ordered one incorporates more VD but, due to the stronger interactions with the carrier, requires a partial dissolution of the matrix to occur before releasing the drug, so inducing a lag-time and a smaller released quantity.

In this study, we assessed the quantity, strength, and acidity of zeolite composites comprising Silicalite-1 grown on ZSM-5 crystals using a combination of infrared (IR) and solid-state nuclear magnetic resonance (NMR) spectroscopy. The composites were created through the direct growth of Silicalite-1 crystals on ZSM-5 (P_ZSM-5), either with or without the organic structure-directing agent (OSDA) introduced into the ZSM-5 channels (samples: H_ZSM-5_Sil1 and TPA_ZSM-5_Sil1). The results revealed that Silicalite-1 grew differently when the ZSM-5 core was in the H+ form (empty pores) compared to when the OSDA was still present in the sample. This distinction was evident in the textural properties, with a decrease in the micropore surface area and an increase in the external surface area in the H_ZSM-5_Sil1 compared to the parent sample. The TPA_ZSM-5_Sil1 composite exhibited characteristics similar to the parent zeolite. These findings were further supported by 29Si NMR, which revealed a comparable local order for the parent (P_ZSM-5) and TPA_ZSM-5_Sil1 samples, along with a broadening of the Q4 peak for the H_ZSM-5_Sil1 composite. Additionally, the acid sites were preserved in the TPA_ZSM-5_Sil1 composite, while in the H+-form core, the concentration of Brønsted acid sites significantly decreased. This reduction in isolated Brønsted acid sites was further corroborated by 1H NMR.

Supercritical fluid technology is an innovative approach that has been extensively explored in various research fields, since it offers a way to limit or replace the use of organic solvents in numerous industrial processes [...]

Capture and storage of CO2 is a topic of great scientific and public interest. At present, the most diffused process for CO2 capture is wet scrubbing, where CO2 is absorbed by liquid amines. However, this system is highly energy-demanding due to the solvent regeneration step; moreover, liquid amines can quickly corrode the employed equipment. As an alternative, solid adsorbents present appealing properties, since they are easier to regenerate and manipulate. In this perspective, the functionalization of mesoporous silica (which offers the advantage of a high specific surface area) with different amines has been explored by using a green solvent, supercritical CO2 (scCO2), in place of the conventional organic ones. Therefore, two amines were loaded on a SBA-15 silica through scCO2 impregnation: the most-commonly-used (3-aminopropyl)triethoxysilane (APTES) and the higher-molecular-weight, 1,6-diaminohexane (DH). The resulting materials were physico-chemically characterized and their capacity of capturing CO2 was evaluated through volumetric tests (CO2 adsorption isotherms at 25 °C) while Fourier Infrared Spectroscopy was employed to characterize in-situ the surface species formed by CO2 adsorption at room temperature. Results show that the amines were successfully loaded on the silica support. Even when these molecules are not anchored through covalent bonds to the surface (as in the case of DH), they are, nevertheless, stable at temperatures compatible with those of the thermal regeneration of the support (120 °C). Interestingly, the so-obtained adsorbents result to be particularly effective in capturing CO2 at low partial pressure.

In this work we evaluate the amount, strength and acidity of defect sites in zeolite composites consisting of Silicalite-1 grown on ZSM-5 crystals by combining IR and solid-state NMR spectroscopy. The composites were prepared by direct growth of Silicalite-1 crystals on ZSM-5 either in the presence or in the absence of the organic structure directing agent (OSDA) (tetrapropylammonium cations, TPA) into the ZSM-5 channels. The results demonstrated that the local order and the concentration of acid sites are preserved in the composite when the OSDA was still present in the parent sample and the growth of Silicalite-1 on the sample occurred homogeneously while in the calcined ZSM-5 sample, the concentration of Brønsted acid sites is significantly lowered due to partial desilication of the parent sample.

The phenomenon of water pollution as a consequence of the release of herbicides and pesticides into the environment is an outgrowing problem that requires performing and regenerable adsorbent materials. This work presents the synthesis of a nanocrystalline silicon carbide aerogel and its application in removing glyphosate from polluted water. The aerogel was synthesized via Polymer-Derived Ceramic (PDC) route using allylhydridopolycarbosilane as polymeric precursor. By pyrolysis at 1500 degrees C in argon, the crystallization of beta-SiC nanocrystals was observed, while the aerogel preserved a high specific surface area of 215 m(2)center dot g(-1). The nanostructured aerogel was tested for glyphosate herbicide, showing a remarkable adsorption of 0.607 mg center dot g(-1), being the initial glyphosate concentration of 2 mg center dot L-1, and a removal of 93% of the pollutant in solution. Elovich kinetics adsorption and Langmuir isotherm models were found to be the most suitable to describe the mechanism of glyphosate capture via adsorption onto the aerogel surface.

Advanced antimicrobial biomaterials for wound healing applications are an active field of research for their potential in addressing severe and infected wounds and overcoming the threat of antimicrobial resistance. Beta-glucans have been used in the preparation of these materials for their bioactive properties, but very little progress has been made so far in producing biomedical devices entirely made of beta-glucans and in their integration with effective antimicrobial agents. In this work, a simple and eco-friendly method is used to produce flexible beta-glucan/nanostructured zinc oxide films, using glucans derived from the yeast Saccharomyces cerevisiae . The properties of the films are characterized through scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, infrared and UV–visible spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and water absorption tests. Finally, the antibacterial properties of the nanostructured zinc oxide and of the composite films are assessed against Staphylococcus epidermidis and Escherichia coli , showing a marked effectiveness against the former. Overall, this study demonstrates how a novel bionanocomposite can be obtained towards the development of advanced wound healing devices.

Chronic wounds are a major concern for global health, affecting millions of individuals worldwide. As their occurrence is correlated with age and age-related comorbidities, their incidence in the population is set to increase in the forthcoming years. This burden is further worsened by the rise of antimicrobial resistance (AMR), which causes wound infections that are increasingly hard to treat with current antibiotics. Antimicrobial bionanocomposites are an emerging class of materials that combine the biocompatibility and tissue-mimicking properties of biomacromolecules with the antimicrobial activity of metal or metal oxide nanoparticles. Among these nanostructured agents, zinc oxide (ZnO) is one of the most promising for its microbicidal effects and its anti-inflammatory properties, and as a source of essential zinc ions. This review analyses the most recent developments in the field of nano-ZnO–bionanocomposite (nZnO-BNC) materials—mainly in the form of films, but also hydrogel or electrospun bandages—from the different preparation techniques to their properties and antibacterial and wound-healing performances. The effect of nanostructured ZnO on the mechanical, water and gas barrier, swelling, optical, thermal, water affinity, and drug-release properties are examined and linked to the preparation methods. Antimicrobial assays over a wide range of bacterial strains are extensively surveyed, and wound-healing studies are finally considered to provide a comprehensive assessment framework. While early results are promising, a systematic and standardised testing procedure for the comparison of antibacterial properties is still lacking, partly because of a not-yet fully understood antimicrobial mechanism. This work, therefore, allowed, on one hand, the determination of the best strategies for the design, engineering, and application of n-ZnO-BNC, and, on the other hand, the identification of the current challenges and opportunities for future research.

Bleeding management is considered essential for saving life both in the military and civilian field. There is still a need to develop topical hemostats that can stop bleeding and be used easily in the trauma sites. The aim of this work is to develop a hemostat based on mesoporous silica particles with large pores for bleeding control. Mesoporous silica microspheres (MSM) with particle size of 1.5 - 5 mu m and pores diameter of 25 nm have been successfully synthesized and, for the first time, loaded with tranexamic acid (TXA) with a content of 4.7%w/w. The hemostatic activity of both the pure material and TXA-loaded material (TXA@MSM) was investigated. It was found that the blood clotting time was significantly shortened by both systems with respect to control. A hemolysis assay was performed to evaluate the hemolytic activity of MSM, and the result indicated that the material was blood compatible. A preliminary TXA in vitro release test was performed, showing the complete release of TXA from the carrier within one hour. Considering the above results, TXA@MSM can be considered a promising material for the development of new hemostats.

The increase in herbicide consumption, in particularly glyphosate, is causing considerable health and environmental concerns, due to its possible carcinogenic effects. Indeed, its widespread and intensive use promotes its diffusion in the surrounding environment. Additionally, the operator's exposure to the herbicide is not negligible.In this work the encapsulation of glyphosate into three selected, eco-friendly silica-and clay-based supports, namely SBA-15, montmorillonite (MMT) and Al pillared montmorillonite (Al-MMT) to promote both a punctual application and a prolonged release of glyphosate is innovatively presented.Preliminary, substrates were characterized pre and post encapsulation through XRD and nitrogen adsorption measurements, to assess the incorporation of the herbicide. Release studies were performed in aqueous matrices of different composition, namely ultrapure water, 0.02 M oxalic pH 3 (simulating acid rains) and 0.01 M CaCl2 solution (simulating soil salinity). Within all these media, Al-MMT exhibited a slow-releasing mechanism, with about 10-20% of glyphosate still retained on the support after 7 days, ascribed to complexation and electrostatic interactions.Three different kinetic models usually applied within controlled-releasing processes, i.e. zero order, pseudo first order and Korsmeyer-Peppas models, were used to describe glyphosate release from Al-MMT in CaCl2 solutions, with Korsmeyer-Peppas model providing the best fit to experimental data (R2 > 0.990). Finally, a water/ soil bench-scaled system was efficiently tested, confirming the successfully applicability of Al-MMT in the prolonged release of glyphosate in real systems.

Nanosized NiO, CeO2 and NiO-CeO2 mixed oxides with different Ni/Ce molar ratios were prepared by the soft template method. All the samples were characterized by different techniques as to their chemical composition, structure, morphology and texture. On the catalysts submitted to the same reduction pretreatment adopted for the activity tests the surface basic properties and specific metal surface area were also determined. NiO and CeO2 nanocrystals of about 4 nm in size were obtained, regardless of the Ni/Ce molar ratio. The Raman and X-ray photoelectron spectroscopy results proved the formation of defective sites at the NiO-CeO2 interface, where Ni species are in strong interaction with the support. The microcalorimetric and Fourier transform infrared analyses of the reduced samples highlighted that, unlike metallic nickel, CeO2 is able to effectively adsorb CO2, forming carbonates and hydrogen carbonates. After reduction in H2 at 400 °C for 1 h, the catalytic performance was studied in the CO and CO2 co-methanation reaction. Catalytic tests were performed at atmospheric pressure and 300 °C, using CO/CO2/H2 molar compositions of 1/1/7 or 1/1/5, and space velocities equal to 72000 or 450000 cm3·h−1·gcat−1. Whereas CO was almost completely hydrogenated in any investigated experimental conditions, CO2 conversion was strongly affected by both the CO/CO2/H2 ratio and the space velocity. The faster and definitely preferred CO hydrogenation was explained in the light of the different mechanisms of CO and CO2 methanation. On a selected sample, the influence of the reaction temperature and of a higher number of space velocity values, as well as the stability, were also studied. Provided that the Ni content is optimized, the NiCe system investigated was very promising, being highly active for the COx co-methanation reaction in a wide range of operating conditions and stable (up to 50 h) also when submitted to thermal stress.

( )Development of high-performance SnO2 anodes is hampered by its peculiar electrochemical behavior, characterized by two processes: conversion and alloying reactions. The conversion reaction being irreversible leads to specific capacities lower than theoretical, however rational design of nanosized SnO(2 )can mitigate this issue, though SnO2 low conductivity and electrode pulverization justify the need of carbon matrices. Some carbon structures proved to be strongly effective at laboratory-scale, but most are too expensive or complicated to obtain for scaling-up. Herein, we exploit the high concentration of oxide and carboxylic surface functional groups of C-NERGY (TM) Super C45 carbon black for one-pot synthesis of ultrafine SnO2 nanoparticles over the carbon surface. These functional groups accomplish the hydrolysis/oxidation of SnCl2, resulting in finely dispersed SnO2 nanoparticles (5 nm in average size) growth over C45. Presence of oxygen species on C45 surface, accessible to tin, prevent fast formation of Li2O, allowing to achieve high capacity and extreme electrode stability. The assembled cells with SnO2/C45 exhibit for more than 400 cycles the reversible capacity of 560 mA h g(-1) per pure SnO2(after subtracting C45 contribution) at 1C, demonstrating prolonged cycling operation thus providing an interesting opportunity for scalable production of stable and high-capacity battery anodes alternatively to graphite. (C) 2020 Elsevier Ltd. All rights reserved.

The use of toxic crosslinking agents and reagents in the fabrication of hydrogels is a frequent issue which is particularly concerning for biomedical or food packaging applications. In this study, novel antibacterial bionanocomposite films were obtained through a simple solvent casting technique without using any crosslinking substance. Films were made from a flexible and transparent whey protein matrix containing zinc oxide nanoparticles synthesised via a wet chemical precipitation route. The physicochemical and functional properties of the ZnO nanoparticles and of the composite films were characterised, and their antibacterial activity was tested against S. epidermidis and E. coli. The synthesised ZnO nanoparticles had an average size of about 30 nm and a specific surface area of 49.5 m2/g. The swelling ratio of the bionanocomposite films increased at basic pH, which is an appealing feature in relation to the absorption of chronic wound exudate. A n-ZnO concentration-dependent antibacterial effect was observed for composite films. In particular, marked antibacterial activity was observed against S. epidermidis. Overall, these findings suggest that this novel material can be a promising and sustainable alternative in the design of advanced solutions for wound dressing or food packaging.