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Excessive exposure to solar radiation causes skin reddening, and sunburn, may accelerate photoaging processes, and lead to neoplastic changes. Therefore, it is recommended to apply cosmetic formulations containing UV protection filters. In recent years, doubts have arisen regarding the safety of certain chemical sunscreen agents that can penetrate the deeper layers of the skin, undergo photodegradation, generate allergies, and affect the endocrine system. The aim of this study was to develop a strategy to limit the permeation of avobenzone from emulsions. Wrinkled mesoporous silicas modified with zinc oxide and/or aminosilane were synthesized, characterized, and next applied as the carriers for the selected UV filter – avobenzone. The introduction of organic groups and ZnO did not disturb the wrinkled morphology of materials, but it changed the textural parameters due to the blocking of micropores. The modification of the wrinkled mesoporous silica had a positive effect on reducing avobenzone rate of desorption. The smallest amount of avobenzone was released from wrinkled mesoporous silica modified with zinc oxide. The release of avobenzone from nanocarriers followed the Korsmeyer-Peppas model, while the diffusion from emulsion was based on the Higuchi model. It was proved that the introduction of avobenzone to functionalized wrinkled mesoporous silica materials reduced the diffusion process of avobenzone from cosmetic emulsions. Nanoporous carriers may help solve the problems related to transepidermal penetration and the potential impact of UV filters on the endocrine system. [Display omitted] • Wrinkled mesoporous silica samples modified with ZnO and aminosilane were obtained. • The materials were applied as avobenzone carriers and introduced to water-in-oil emulsions. • Zinc oxide, amine functional groups, and porosity of silica governed UV filter release. • The modification of the wrinkled mesoporous silica reduced release rate of avobenzone. • The SPF value of emulsion with hybrid system was 25% higher than for free Avo formulation. [ABSTRACT FROM AUTHOR]

Abstract Mesoporous carbon was functionalized with amino groups and the acid-base properties of its surface were analyzed. Next multiple light scattering was applied to determine the stability of these materials. It was shown that the lower amount of amino groups were on the surface of mesoporous carbons the more stable was the dispersion in water. The enhancement in dispersion stability of the sample containing the highest amount of basic groups on the surface was achieved after the addition of surfactant. The results of these studies proved that multiple light scattering could be successfully applied as a new tool to characterize nanomaterials immersed in different solvents. Graphical abstract Unlabelled Image Highlights • Amino groups were grafted on the surface of mesoporous carbons. • Functionalization of carbons significantly affected their surface properties. • Multiple light scattering was applied to assess the stability dispersion of the materials. • The lowest stability was observed for carbon modified with tetraethylenepentamine. • Addition of surfactant could improve the dispersion stability of mesoporous carbons. [ABSTRACT FROM AUTHOR]

In this study, 3-aminopropyltriethoxysilane (APTES) was grafted on the surface of oxidized mesoporous carbon of cubic structure. The process of modification was carried out at 40 °C for 8 h with increasing amount of aminosilane (1.2, 3, 6 mL). The new hybrid materials were characterized by FT-IR spectroscopy, low temperature nitrogen sorption, scanning electron microscopy, elemental analysis, thermogravimetric methods, Boehm titration, laser diffraction, dynamic and multiple light scattering. Functionalization of carbon with aminosilane significantly affected its structural, textural and surface properties. The chemical interaction of aminosilane with the oxidized carbon material was confirmed by FT-IR spectra. Thermogravimetric analysis of the functionalized mesoporous carbons exhibited three peaks at temperatures in the range 60–650 °C that correspond to the degradation of chemically grafted aminosilane on the materials surface. Multiple light scattering was applied to assess the stability of the materials in water, toluene and Tween 80 non-ionic surfactant solutions. In polar solvent all aminosilane-grafted mesoporous carbons were more stable than the unmodified material. In toluene and surfactant solution the sample modified with the lowest amount of APTES showed the highest stability. Additionally, it was proved that the more acidic groups were on the surface of mesoporous carbons the more stable was the dispersion in surfactant solution. [ABSTRACT FROM AUTHOR]

In this study the mesoporous silicas SBA-15 and SBA-16 were functionalized with 3-aminopropyltriethoxysilane (APTES). The materials obtained were characterized by infrared spectroscopy, X-ray diffraction, low-temperature nitrogen sorption, laser diffraction, elemental analysis, zeta potential measurements, scanning and transmission electron microscopy. The introduction of amine groups changes the textural parameters of mesoporous materials. Antipyrine was selected as a model drug to be loaded on the modified mesoporous silica and released in the medium of the simulated gastric fluid and phosphate buffer with a pH of 7.2. The antipyrine adsorption process was more effective onto the pure silica than onto amino-functionalized samples. Furthermore, it was proved that SBA-16 with cubic structure was a better drug vehicle than SBA-15 with hexagonal structure. The release behaviour of antipyrine was highly dependent on the surface properties of mesoporous materials. The presence of amine groups on the surface of silica was found to increase the amount and rate of antipyrine release regardless of the pH conditions. [ABSTRACT FROM AUTHOR]

Mesoporous carbons obtained by soft and hard template methods were oxidized by ammonium persulfate under different conditions. The functional groups present on the surface of carbon materials were identified by FT-IR and thermogravimetric studies. Longer time of oxidation process was favorable for generation of higher density of carboxylic, phenolic and etheric groups. The stability of pristine and functionalized mesoporous carbons dispersed in water was analyzed by multiple light scattering and laser diffraction methods. Additionally, the zeta potential of mesoporous carbons suspensions was measured. Particle–particle interactions, particle size and their density determined the sedimentation behavior of materials in aqueous solution. Non-modified C KIT-6 and C SBA-15 exhibited higher transmission level than the oxidized materials. Higher transmission intensity is related to more intense sedimentation. The results indicate that the dispersion of functionalized C KIT-6 and C SBA-15 in a liquid phase is much more stable than that of non-modified mesoporous carbon materials. In contrast, for the carbon samples obtained by the soft template method, the modification did not produce significant changes in the intensity of back-scattered light. [ABSTRACT FROM AUTHOR]

Highlight: [•] Mesoporous carbons CMK-3 and CMK-8 were prepared by hard template method. [•] Adsorption of l-phenylalanine was studied from solutions with different pH. [•] Electrostatic, hydrophobic, steric interactions are important in l-Phe adsorption. [•] Sorption capacities decrease in the following order: CMK-8>CMK-3>KIT-6>SBA-15. [•] Adsorption of l-Phe leads to a decrease in surface area and pore volume of carbons. [Copyright &y& Elsevier]

Abstract: Mesoporous silica materials, such as SBA-3, SBA-15, SBA-16 and KIT-6 were synthesized using tetraethyl orthosilicate as the silica source and different surfactants as templates. The products were characterised by a number of techniques, including low-temperature nitrogen sorption, X-ray diffraction and transmission electron microscopy. Results of the studies confirmed the ordered mesoporous structures of all silica samples obtained. Adsorption of l-phenylalanine on various mesoporous adsorbents was studied from solutions with different pH (5.6–9.4). Maximum sorption capacity was observed at pH 5.6, which is close to the isoelectric point of l-phenylalanine (pI = 5.48). Above this pH value, the amount of adsorbed amino acid decreased. In the range of equilibrium concentration (pH 5.6), the adsorption capacities of ordered silica samples decreased in the following order: KIT-6 (420 μmol g−1) > SBA-15 (389 μmol g−1) > SBA-16 (357 μmol g−1) > SBA-3 (219 μmol g−1). The lowest sorption capacity towards l-phenylalanine was found for SBA-3 despite the fact that it showed the largest surface area, which can be explained assuming that part of the pores in SBA-3 can be inaccessible to l-phenylalanine molecules. Large pore size of KIT-6 and SBA-15 permitted the amino acid molecule to enter into the pores of these mesoporous molecular sieves. [Copyright &y& Elsevier]

Highlights: [•] SBA-15, SBA-16, KIT-6 materials were prepared by hydrothermal method. [•] Ordered mesoporous silicas are promising as adsorbents of l-phenylalanine. [•] Adsorption of l-phenylalanine was studied from solutions with different pH. [•] Sorption capacities decrease in the following order: KIT-6>SBA-15>SBA-16. [•] L-Phe release rate exhibited the pH sensitivity. [Copyright &y& Elsevier]

The adsorption of amino acids such as l-phenylalanine and l-histidine was carried out on a series of mesoporous carbons obtained with the use ordered silicas KIT-6, SBA-16, SBA-15 as templates and furfuryl alcohol as carbon precursor. Small angle XRD analysis confirmed the ordered mesoporous structures of all materials obtained. They were also characterised by well-developed surface areas and high pore volumes. Adsorption behaviour of amino acids on ordered mesoporous carbons was investigated in potassium phosphate buffer solutions with adjustable l-phenylalanine and l-histidine concentration, ion strength, and pH. The highest sorption capacity towards the amino acids were observed at pH close to the isoelectric point of l-phenylalanine (pI = 5.48) and l-histidine (pI = 7.59). Electrostatic, hydrophobic and steric interactions had very strong effect on the adsorption of amino acids on mesoporous carbons. The amount of l-phenylalanine and l-histidine adsorbed decreased in the following sequence: C > C > C that was strongly related to their structure, surface areas and average pore diameters. [ABSTRACT FROM AUTHOR]

Recently, great attention has been paid to hydroxychloroquine which after promising in vitro studies has been proposed to treat the severe acute respiratory syndrome caused by SARS-CoV-2. The clinical trials have shown that hydroxychloroquine was not as effective as was expected and additionally, several side effects were observed in patients cured with this medicament. In order to reduce them, it is suggested to deliver hydroxychloroquine in a controlled manner. Therefore, in this study non-modified (SBA-15, SBA-16) and modified with copper and aminosilane mesoporous silica materials were applied as novel nanocarriers for hydroxychloroquine. First, pristine and functionalized samples were synthesized and characterized by X-ray diffraction, low-temperature nitrogen sorption, transmission electron microscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, laser diffraction. Then the influence of physicochemical parameters of materials obtained on the adsorption and release processes of hydroxychloroquine was analyzed. The mechanism of hydroxychloroquine binding to non-modified silicas was based on the formation of hydrogen bonds, while in the case of copper and aminosilane functionalized materials the complexes with drug molecules were generated. The release behavior of hydroxychloroquine from silica samples obtained was determined by different factors including pH conditions, textural parameters, surface charge, and presence of surface functional groups. The greatest differences in hydroxychloroquine release profiles between materials were observed at pH 7.2. The amount of drug desorbed from silica decreased in the following order: functionalized SBA-15 (84%) > functionalized SBA-16 (79%) > SBA-15 (59%) > SBA-16 (33%). It proved that a higher amount of drug was released from materials of hexagonal structure. [Display omitted] • Novel mesoporous silica carriers for hydroxychloroquine antiviral drug were prepared. • Modification of silica with copper and aminosilane determined their sorption properties. • The complexes between copper and drug molecules on the surface of silica were generated. • The greatest differences in hydroxychloroquine release profiles were observed at pH 7.2. • The higher amount of drug was released from silica materials of hexagonal structure. [ABSTRACT FROM AUTHOR]

The oxidized ordered mesoporous carbons of cubic and hexagonal structure obtained by two templating methods (soft and hard) were applied for the first time as delivery systems for paracetamol—the most common antipyretic and analgesic drug in the world. The process of carbon oxidation was performed using an acidic ammonium persulfate solution at 60 °C for 6 h. The functionalization was found to reduce the specific surface area and pore volume of carbon materials, but it also led to an increasing number of acidic oxygen-containing functional groups. The most important element and the novelty of the presented study was the evaluation of adsorption and release ability of carbon carriers towards paracetamol. It was revealed that the sorption capacity and the drug release rate were mainly affected by the materials' textural parameters and the total amount of surface functional groups, notably different in pristine and oxidized samples. The adsorption of paracetamol on the surface of ordered mesoporous carbons occurred according to different mechanisms: donor–acceptor complexes and hydrogen bond formation. The adsorption kinetics was assessed using pseudo-first- and pseudo-second-order models. The regression results indicated that the adsorption kinetics was more accurately represented by the pseudo-second-order model. Paracetamol was adsorbed onto the carbon materials studied following the Langmuir type isotherm. The presence of oxygen-containing functional groups on the surface of ordered mesoporous carbons enhanced the amount of paracetamol adsorbed and its release rate. The optimal drug loading capacity and expected release pattern exhibited oxidized ordered mesoporous carbon with a hexagonal structure obtained by the hard template method. [ABSTRACT FROM AUTHOR]

Ibuprofen (IBU) was chosen as a model drug to investigate the drug delivery rate. Mesoporous MCM-41 has been charged with ibuprofen (MCM-41_IBU). Calcium alginate was applied to encapsulate free drug and the mesoporous material. The system with double barrier demonstrated a slower release of IBU than free ibuprofen-loaded alginate beads and MCM-41_IBU. The IBU release from alginate matrix can be controlled by adjusting the free IBU/MCM-41_IBU ratio. [ABSTRACT FROM AUTHOR]