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In this study, a silica matrix was utilized as a substrate for zinc oxide nanoparticles (ZnO NPs) to enhance their photocatalytic activity for the degradation of methylene blue (MB) dye. The recovery of the prepared material was also investigated. To compare the performance of the prepared material with ZnO NPs and bare silica, various analyses were conducted. ZnO NPs were synthesized via a coprecipitation method and characterized using Fourier-transform infrared spectra and X-ray diffraction (XRD). The XRD results revealed highly crystalline ZnO NPs with an average crystallite size of less than 100 nm. The presence of ZnO on the silica matrix was confirmed using scanning electron microscopy (SEM) and EDX analysis. The prepared ZnO NPs showed enhanced photocatalytic activity for the degradation of MB dye, and reasonable material recovery was also observed. The silica-coated ZnO NPs degraded MB dye by 97% in just 40 min and retained their photocatalytic activity for up to 20 cycles. In comparison, bare silica exhibited effective photodegradation but lost its photodegradation capacity after five cycles. ZnO NPs without silica coating took 5 h to degrade MB dye. The significant accomplishment in this study is the development of novel materials with high recoverability, simple preparation, and efficient photocatalytic activity. In the future, ZnO NPs supported on a silica matrix can be utilized for various applications.

This work presents the effect of monovalent (Ag+, Na+), divalent (Ca2+, Cd2+), and trivalent (La3+) metal ion doping and annealing temperature (500, 800, and 1200 °C) on the structure, morphology, and magnetic properties of MnFe2O4/SiO2 ceramic nanocomposites synthesized via sol–gel method. Fourier-transform infrared spectroscopy confirms the embedding of undoped and doped MnFe2O4 nanoparticles in the SiO2 matrix at all annealing temperatures. In all cases, the X-ray diffraction (XRD) confirms the formation of MnFe2O4. In the case of undoped, di-, and trivalent metal-ion-doped gels annealed at 1200 °C, three crystalline phases (cristobalite, quartz, and tridymite) belonging to the SiO2 matrix are observed. Doping with mono- and trivalent ions enhances the nanocomposite's structure by forming single-phase MnFe2O4 at low annealing temperatures (500 and 800 °C), while doping with divalent ions and high annealing temperature (1200 °C) results in additional crystalline phases. Atomic force microscopy (AFM) reveals spherical ferrite particles coated by an amorphous layer. The AFM images showed spherical particles formed due to the thermal treatment. The structural parameters calculated by XRD (crystallite size, crystallinity, lattice constant, unit cell volume, hopping length, density, and porosity) and AFM (particle size, powder surface area, and thickness of coating layer), as well as the magnetic parameters (saturation magnetization, remanent magnetization, coercivity, and anisotropy constant), are contingent on the doping ion and annealing temperature. By doping, the saturation magnetization and magnetocrystalline anisotropy decrease for gels annealed at 800 °C, but increase for gels annealed at 1200 °C, while the remanent magnetization and coercivity decrease by doping at both annealing temperatures (800 and 1200 °C). [ABSTRACT FROM AUTHOR]

Nanocrystalline Selenium was synthesized within a silica matrix using a sol-gel method with high-purity SeO2, ethyl alcohol, distilled water, and TEOS (Tetraethyl orthosilicate). This process encapsulated the selenium dioxide in the silica matrix, which was then reduced at about 100°C using an oil bath. Three reducing agents were employed: acetone vapor, and sodium borohydride (NaBH4) and hydrazine (N2H4) in liquid form. DSC-TGA analyses of the precursor mixture determined the crystallization temperature for selenium nanoparticle formation within the matrix to be around 100°C. Post-heating phase analysis via XRD revealed hexagonal structures, with crystallite sizes between 33 and 43 nm determined using Debye-Scherrer's formula. Morphological studies showed irregular polygonal shapes with rough surfaces, with particulate sizes under 0.2μ for acetone vapor, around 0.1μ for hydrazine, and slightly over 0.1μ for sodium borohydride. Time variations were explored to observe phase and crystallite size changes. FTIR analysis was conducted for bonding assessment, revealing M-O coordination. The composite's absorbance was examined through UV-VIS spectroscopy, and its morphological attributes were investigated using FESEM analysis, complemented by EDX to determine elemental composition. [ABSTRACT FROM AUTHOR]

CoFe2O4 is a promising functional material for various applications. The impact of doping with different cations (Ag+, Na+, Ca2+, Cd2+, and La3+) on the structural, thermal, kinetics, morphological, surface, and magnetic properties of CoFe2O4 nanoparticles synthesized via the sol-gel method and calcined at 400, 700 and 1000 °C is investigated. The thermal behavior of reactants during the synthesis process reveals the formation of metallic succinates up to 200 °C and their decomposition into metal oxides that further react and form the ferrites. The rate constant of succinates' decomposition into ferrites calculated using the isotherms at 150, 200, 250, and 300 °C decrease with increasing temperature and depend on the doping cation. By calcination at low temperatures, single-phase ferrites with low crystallinity were observed, while at 1000 °C, the well-crystallized ferrites were accompanied by crystalline phases of the silica matrix (cristobalite and quartz). The atomic force microscopy images reveal spherical ferrite particles covered by an amorphous phase, the particle size, powder surface area, and coating thickness contingent on the doping ion and calcination temperature. The structural parameters estimated via X-ray diffraction (crystallite size, relative crystallinity, lattice parameter, unit cell volume, hopping length, density) and the magnetic parameters (saturation magnetization, remanent magnetization, magnetic moment per formula unit, coercivity, and anisotropy constant) depend on the doping ion and calcination temperature. [ABSTRACT FROM AUTHOR]

In recent years, during industrial development, the expanding discharge of harmful metallic ions from different industrial wastes (such as arsenic, barium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, or zinc) into different water bodies has caused serious concern, with one of the problematic elements being represented by selenium (Se) ions. Selenium represents an essential microelement for human life and plays a vital role in human metabolism. In the human body, this element acts as a powerful antioxidant, being able to reduce the risk of the development of some cancers. Selenium is distributed in the environment in the form of selenate (SeO42–) and selenite (SeO32–), which are the result of natural/anthropogenic activities. Experimental data proved that both forms present some toxicity. In this context, in the last decade, only several studies regarding selenium's removal from aqueous solutions have been conducted. Therefore, in the present study, we aim to use the sol–gel synthesis method to prepare a nanocomposite adsorbent material starting from sodium fluoride, silica, and iron oxide matrices (SiO2/Fe(acac)3/NaF), and to further test it for selenite adsorption. After preparation, the adsorbent material was characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The mechanism associated with the selenium adsorption process has been established based on kinetic, thermodynamic, and equilibrium studies. Pseudo second order is the kinetic model that best describes the obtained experimental data. Also, from the intraparticle diffusion study, it was observed that with increasing temperature the value of the diffusion constant, Kdiff, also increases. Sips isotherm was found to best describe the experimental data obtained, the maximum adsorption capacity being ~6.00 mg Se(IV) per g of adsorbent material. From a thermodynamic point of view, parameters such as ΔG0, ΔH0, and ΔS0 were evaluated, proving that the process studied is a physical one. [ABSTRACT FROM AUTHOR]

(Co0.4Zn0.4Ni0.2Fe2O4)α(SiO2)(100−α) samples obtained by embedding Co0.4Zn0.4Ni0.2Fe2O4 nanoparticles in SiO2 in various proportions were synthesized by sol-gel process and characterized using thermal analysis, Fourier-transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, inductively coupled plasma optical emission spectrometry, and magnetic measurements. Poorly crystalline Co–Zn–Ni ferrite at low annealing temperatures (500 °C) and highly crystalline Co–Zn–Ni ferrite together with traces of crystalline Fe2SiO4 (800 °C) and SiO2 (tridymite and cristobalite) (1200 °C) were obtained. At 1200 °C, large spherical particles with size increasing with the ferrite content (36–120 nm) were obtained. Specific surface area increased with the SiO2 content and decreased with the annealing temperature above 500 °C. Magnetic properties were enhanced with the increase in ferrite content and annealing temperature. [ABSTRACT FROM AUTHOR]

Biomass chemical looping gasification has attracted wide attention in syngas production. However, the major obstacle is deactivation of oxygen carriers (OCs) caused by sintering, leading to low gasification efficiency. Developing sintering-resistant oxygen carriers is crucial for enhancing the competitiveness of BCLG. This study proposes an effective strategy of embedding NiFe 2 O 4 in silica matrix (NFSM) to fabricate highly dispersed OCs. The gasification performance and cycling stability of OCs for BCLG are systematically researched in a fixed-bed reactor. Based on the characterization analysis, NiFe 2 O 4 is successfully incorporated into the silica matrix. The well-dispersed active components in OCs create more oxygen vacancies and metal adsorption sites, resulting in higher redox activity. Experimental results verify that the optimal parameters for achieving the highest syngas yield (1254 mL/g) and biomass gasification efficiency (68 %) are 0.6 OCs/B, a temperature of 850 °C, and a water injection rate of 0.3 mL/min. After 10 redox cycles, NFSM demonstrates superior redox activity and excellent cycle stability, maintaining its gasification performance and microstructural integrity throughout all chemical looping gasification processes. The silica matrix-supported NiFe 2 O 4 can be a promising candidate for BCLG. This work provides a novel approach to develop and design future OCs of BCLG for alleviating sintering and deactivation phenomena. [Display omitted] • Silica matrix significantly improves the sintering resistance of NiFe 2 O 4. • High oxygen vacancy concentrations contribute to the enhanced catalytic activity. • The orthogonal tests of temperature and water injection rate are carried out. • NFSM possesses the desired redox activity and syngas yield. • NFSM exhibits excellent stability over multiple cycles. [ABSTRACT FROM AUTHOR]

The antibacterial activity of zinc oxide particles has received significant interest worldwide, especially through the implementation of technology to synthesize particles in the nanometer range. This study aimed to determine the antimicrobial efficacy of silica-based iron oxide matrix (SiO2FexOy) synthesized with various amounts of ZnO (SiO2FexOyZnO) against various pathogens. It is observed that, with the addition of ZnO to the system, the average size of the porosity of the material increases, showing increasingly effective antibacterial properties. Zinc-iron-silica oxide matrix composites were synthesized using the sol–gel method. The synthesized materials were investigated physicochemically to highlight their structural properties, through scanning electron microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), and Fourier-transform infrared spectroscopy (FT-IR). At the same time, surface area, pore size and total pore volume were determined for materials synthesized using the Brunauer–Emmett–Teller (BET) method. Although the material with 0.0001 g ZnO (600 m2/g) has the highest specific surface area, the best antimicrobial activity was obtained for the material with 1.0 g ZnO, when the average pore volume is the largest (~8 nm) for a specific surface of 306 m2/g. This indicates that the main role in the antibacterial effect has reactive oxygen species (ROS) generated by the ZnO that are located in the pores of the composite materials. The point of zero charge (pHpZc) is a very important parameter for the characterization of materials that indicate the acid-base behaviour. The pHpZc value varies between 4.9 and 6.3 and is influenced by the amount of ZnO with which the iron-silica oxide matrix is doped. From the antimicrobial studies carried out, it was found that for S. aureus the total antibacterial effect was obtained at the amount of 1.0 g ZnO. For Gram-negative bacteria, a total antibacterial effect was observed in S. flexneri (for the material with 0.1 g ZnO), followed by E. coli (for 1.0 g ZnO). For P. aeruginosa, the maximum inhibition rate obtained for the material with 1.0 g ZnO was approximately 49%. [ABSTRACT FROM AUTHOR]

Lithium ferrite nanoparticles dispersed in silica matrix [Li0.5Fe2.5O4]1–x[SiO2]x (x = 0, 50–90%) have been synthesized using ultrasonic assisted sol–gel method. Agglomeration due to higher surface energy and interparticle interactions is reduced due to dispersion in silica; which modifies the nanoparticle surface and revamp properties of the system. X–ray diffractometer (XRD) measurement reveals simple cubic spinel structure without any impurities. Dynamic magnetic field susceptibility studies show that reversible nature of magnetic domain walls dominates over the irreversible nature. Energy band gap (Eg) determined from UV–Visible (UV–Vis) spectroscopy shows an escalation (1.47 eV to 1.59 eV) for change in silica from 0% to 90%. An empirical formula for refractive index as μ = A(silica content)2+B(silica content)+C has been derived using theoretical fit. With increase in silica content, the refractive index, optical dielectric constant, dielectric susceptibility and oxygen packing density show decrements from 3.82 to 1.77, 8.1204 to 7.6825, 0.6465 to 0.6117 and 70.3157 to 60.974, respectively. The reflectivity, absorption coefficient, molar refractive index, molar electronic polarizability, reflection loss, polaron radius and optical basicity also show reduction. This is attributed to change in density and interparticle interaction due to change in silica content. Dielectric polarizability, transmission coefficient and metallization criterion show increment from 14.85 Å3 to 39.29 Å3, 0.5968 to 0.6086 and 0.2698 to 0.2808; respectively. Observed effects have been ascribed to higher strain, reduction in reflection loss and more non-metallic nature of the samples. Swift changes in parameters indicate their fine tuning through optimum magnitude of silica.

This work presents the effect of monovalent (Ag+, Na+), divalent (Ca2+, Cd2+), and trivalent (La3+) metal ion doping and annealing temperature (500, 800, and 1200 °C) on the structure, morphology, and magnetic properties of MnFe2O4/SiO2 ceramic nanocomposites synthesized via sol–gel method. Fourier-transform infrared spectroscopy confirms the embedding of undoped and doped MnFe2O4 nanoparticles in the SiO2 matrix at all annealing temperatures. In all cases, the X-ray diffraction (XRD) confirms the formation of MnFe2O4. In the case of undoped, di-, and trivalent metal-ion-doped gels annealed at 1200 °C, three crystalline phases (cristobalite, quartz, and tridymite) belonging to the SiO2 matrix are observed. Doping with mono- and trivalent ions enhances the nanocomposite’s structure by forming single-phase MnFe2O4 at low annealing temperatures (500 and 800 °C), while doping with divalent ions and high annealing temperature (1200 °C) results in additional crystalline phases. Atomic force microscopy (AFM) reveals spherical ferrite particles coated by an amorphous layer. The AFM images showed spherical particles formed due to the thermal treatment. The structural parameters calculated by XRD (crystallite size, crystallinity, lattice constant, unit cell volume, hopping length, density, and porosity) and AFM (particle size, powder surface area, and thickness of coating layer), as well as the magnetic parameters (saturation magnetization, remanent magnetization, coercivity, and anisotropy constant), are contingent on the doping ion and annealing temperature. By doping, the saturation magnetization and magnetocrystalline anisotropy decrease for gels annealed at 800 °C, but increase for gels annealed at 1200 °C, while the remanent magnetization and coercivity decrease by doping at both annealing temperatures (800 and 1200 °C).

This study aims to remove arsenic from an aqueous medium by adsorption on a nanocomposite material obtained by the sol–gel method starting from matrices of silica, iron oxide and NaF (SiO2/Fe(acac)3/NaF). Initially, the study focused on the synthesis and characterization of the material by physico–chemical methods such as: X-ray diffraction, FT-IR spectroscopy, Raman spectroscopy, atomic force microscopy, and magnetization. Textural properties were obtained using nitrogen adsorption/desorption measurements. The zero load point, pHpZc, was also determined by the method of bringing the studied system into equilibrium. In addition, this study also provides a comprehensive discussion of the mechanism of arsenic adsorption by conducting kinetic, thermodynamic and equilibrium studies. Studies have been performed to determine the effects of adsorbent dose, pH and initial concentration of arsenic solution, material/arsenic contact time and temperature on adsorption capacity and material efficiency. Three theoretical adsorption isotherms were used, namely Langmuir, Freundlich and Sips, to describe the experimental results. The Sips isotherm was found to best describe the experimental data obtained, the maximum adsorption capacity being ~575 µg As(III)/g. The adsorption process was best described by pseudo-second order kinetics. Studies have been performed at different pH values to establish not only the optimal pH at which the adsorption capacity is maximum, but also which is the predominantly adsorbed species. The effect of pH and desorption studies have shown that ion exchange and the physiosorption mechanism are implicated in the adsorption process. From a thermodynamic point of view, parameters such as ΔG°, ΔH° and ΔS° were evaluated to establish the mechanism of the adsorption process. Desorption studies have been performed to determine the efficiency of the material and it has been shown that the material can be used successfully to treat a real-world example of deep water with a high arsenic content. [ABSTRACT FROM AUTHOR]

Liquid‐infused surfaces are based upon the infusion of a liquid phase into a porous solid material to induce slippery and repellent character. In this context, porous SiOx plasma polymer films represent a relevant candidate for a robust nanoporous carrier layer. Intermittent low‐pressure plasma etching of O2/hexamethyldisiloxane‐derived coatings is investigated to enhance the intrinsic porosity inherent to residual hydrocarbons in the silica matrix. Simulations of the resulting Si–O ring network structure using reactive molecular dynamics indicate formation of interconnected voids with Si–OH functionalized pore walls allowing water penetration with almost Fickian diffusive behavior. The corresponding porosity of up to 18%, well agreeing with simulations, Fourier‐transform infrared spectroscopy, and ellipsometry measurements, was found to be suitable for the liquid infusion of polyethylene glycol molecules into about 80 nm thick SiOx films providing ongoing lubricating properties, thus revealing their suitability as liquid‐infused surfaces. [ABSTRACT FROM AUTHOR]

The application of rare earth (RE)-based phosphor materials faces a significant challenge in adopting strategies to bring down the cost without compromising their properties. The most straightforward approach is to minimize the use of RE elements. Herein, we demonstrate the use of SiO 2 as an economical solid nano-matrix for lanthanides-based phosphor nanomaterials. Gd 2 O 3 :Eu3+(x %) and Gd 2 O 3 :Eu3+(x %)/SiO 2 nanophosphor composites were prepared through a modified soft templating technique using cetyltrimethylammonium bromide (CTAB) as the surfactant. The photoluminescence properties were studied by excitation, emission, and luminescence decay investigations. Upon excitation in the O2−(2p)→Eu3+(4f6) LMCT state, these nanophosphors exhibited predominantly red emission from the 5D 0 →7F J transition (where J = 0–4) of the Eu3+ ion. Moreover, the synthesized low-cost Gd 2 O 3 Eu3+(5 %)/SiO 2 composites, with a small number of lanthanides, exhibited excellent photocatalytic degradation activity for organic dye (methylene blue) under visible light (λ ≥ 420 nm), showing promising potential for photocatalytic wastewater treatment. We report the use of SiO 2 as an economical solid nano-matrix for lanthanides-based Gd 2 O 3 :Eu3+(x %)/SiO 2 nanophosphor composites through a modified soft templating technique using cetyltrimethylammonium bromide (CTAB) as the conventional surfactant. [Display omitted] • Conventional surfactant CTAB micelle was modified with lanthanides counterions. • Low-cost nanophosphor composites synthesis was employed vial soft template. • The composites showed best ligand to metal energy transfer mechanism. • Rapid catalytic activity is demonstrated by down conversion Gd 2 O 3 :Eu3+/SiO 2 composite. [ABSTRACT FROM AUTHOR]

In recent years, during industrial development, the expanding discharge of harmful metallic ions from different industrial wastes (such as arsenic, barium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, or zinc) into different water bodies has caused serious concern, with one of the problematic elements being represented by selenium (Se) ions. Selenium represents an essential microelement for human life and plays a vital role in human metabolism. In the human body, this element acts as a powerful antioxidant, being able to reduce the risk of the development of some cancers. Selenium is distributed in the environment in the form of selenate (SeO42–) and selenite (SeO32–), which are the result of natural/anthropogenic activities. Experimental data proved that both forms present some toxicity. In this context, in the last decade, only several studies regarding selenium’s removal from aqueous solutions have been conducted. Therefore, in the present study, we aim to use the sol–gel synthesis method to prepare a nanocomposite adsorbent material starting from sodium fluoride, silica, and iron oxide matrices (SiO2/Fe(acac)3/NaF), and to further test it for selenite adsorption. After preparation, the adsorbent material was characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The mechanism associated with the selenium adsorption process has been established based on kinetic, thermodynamic, and equilibrium studies. Pseudo second order is the kinetic model that best describes the obtained experimental data. Also, from the intraparticle diffusion study, it was observed that with increasing temperature the value of the diffusion constant, Kdiff, also increases. Sips isotherm was found to best describe the experimental data obtained, the maximum adsorption capacity being ~6.00 mg Se(IV) per g of adsorbent material. From a thermodynamic point of view, parameters such as ΔG0, ΔH0, and ΔS0 were evaluated, proving that the process studied is a physical one.

In the present article, we synthesise the Sm(DBM) 3 phen (SmDP), silica nanoparticles (SiNP) and Sm(DBM) 3 phen functionalized SiNPs (SiNP_SmDP), which were prepared using the modified Stober method. SEM images revealed an average Si NPs diameter of ∼324 nm. The absorption spectra of the samples showed broad absorption bands in the UV-blue region. Photoluminescence spectra revealed the broadband emission of SiNP centred at 435 nm; and sharp emission peaks corresponding to SmDP due to Sm3+ ion at 567 nm, 609 nm, and 650 nm ascribed due to the transitions 4G 5/2 → 6H 5/2 , 4G 5/2 → 6H 7/2 , and 4G 5/2 → 6H 9/2 , respectively. The SiNP_SmDP's emission spectra consist of amalgam emission with broadband due to SiNP; and sharps peaks due to SmDP complex. Under 405 nm laser excitation, the opto-thermal properties of SiNP_SmDP were explored in the range 293K–313K temperature. CIE coordinate analysis illustrates how colour perception varies with temperature. The maximum sensitivities values are 0.00816 K−1, 1.6326%K−1 and 0.00974 K−1, 3.43743%K−1 corresponding to the transitions 4G 5/2 → 6H 5/2 : 4G 5/2 → 6H 7/2 and 4G 5/2 → 6H 5/2 : 4G 5/2 → 6H 9/2 of Sm3+ ions. Graphical abstract representing the emission of Silica nanoparticles (SiNP), Sm(DBM) 3 phen (SmDP) and SiNP:SmDP and temperature sensing properties of SiNP:SmDP. [Display omitted] • Synthesis of Silica nanoparticles, Sm(DBM) 3 Phen complex, and SiNP functionalized Sm(DBM) 3 Phen complex. • Study of excitation and temperature depdedent PL of composite. • Analysed the variation of emission spectra with temperature using CIE coordinates and FIR methods. • The maximum values of thermal absolute and relative sensitivities were estimated. [ABSTRACT FROM AUTHOR]

This paper presents the results of research on a luminescent dye bound in a silica matrix. The new developed dye from the group of azaheterocyclic compounds was used: 3-(p-hydroxyphenyl)-1-phenyl-1H-pyrazolo [3,4-b]quinoxaline. The structure and composition of the dye was examined by 1HNMR, 13CNMR, FTIR, and elemental analysis. Its absorption and photoluminescence characteristics were tested in solvents of different polarity in UV-Vis range. The films were prepared by sol–gel method and dip-coating technique. The dye was introduced into a sol in the course of a synthesis of the latter. DLS and FTIR measurements of sols were performed. Optical properties were investigated using UV-Vis spectrophotometry and monochromatic ellipsometry. The surface morphology of the layers was examined by atomic force microscopy. Our investigations showed that the dye bound in the silica matrix does not lose its photoluminescent properties. The emission band at λPL = 550 nm (λex = 365 nm) was recorded for the dye in the matrix. The layers are optically homogeneous with smooth surfaces. Dye doped silica films have RMS surface roughness of 2.17 nm over areas of 2 × 2 μm2. The idea of binding a photoluminescent dye in a silica matrix presented in the paper can be applied in the technology of luminescent solar concentrators. [ABSTRACT FROM AUTHOR]

In the present study, stabilizer caged fluorescent rhodamine B mesoporous silica particles with special shapes were prepared. The prepared particles have a pore volume of 1.92 cm3/g and a pore diameter of 12 nm. The abundant hydroxyl functional groups of mesoporous silica are responsible for the superior loading capacity of target molecular specie. The appearance of bands due to –COOH, –CH3, –CH2, –NH etc. indicated that the fluorescent rhodamine B could be encaged with the stabilizer inside the mesoporous channels. The performance of mesostructured origami silica matrix was evaluated by in vitro release experiments. From the in vitro release results, this material is suggested to have appropriate features for almost no release at pH = 1.2 and very slow release at neutral pH value. The same material could be best employed at pH 4.5 and at high pH values. It is concluded that mesostructured origami silica matrix is a smart nano-platform and can be utilized for high retention of cargo molecules.

Abstract Background The use of sequencing and genotyping platforms has undergone dramatic improvements, enabling the generation of a wealth of genomic information. Despite this progress, the availability of high-quality genomic DNA (gDNA) in sufficient concentrations is often a main limitation, especially for third-generation sequencing platforms. A variety of DNA extraction methods and commercial kits are available. However, many of these are costly and frequently give either low yield or low-quality DNA, inappropriate for next generation sequencing (NGS) platforms. Here, we describe a fast and inexpensive DNA extraction method (SILEX) applicable to a wide range of plant species and tissues. Results SILEX is a high-throughput DNA extraction protocol, based on the standard CTAB method with a DNA silica matrix recovery, which allows obtaining NGS-quality high molecular weight genomic plant DNA free of inhibitory compounds. SILEX was compared with a standard CTAB extraction protocol and a common commercial extraction kit in a variety of species, including recalcitrant ones, from different families. In comparison with the other methods, SILEX yielded DNA in higher concentrations and of higher quality. Manual extraction of 48 samples can be done in 96 min by one person at a cost of 0.12 €/sample of reagents and consumables. Hundreds of tomato gDNA samples obtained with either SILEX or the commercial kit were successfully genotyped with Single Primer Enrichment Technology (SPET) with the Illumina HiSeq 2500 platform. Furthermore, DNA extracted from Solanum elaeagnifolium using this protocol was assessed by Pulsed-field gel electrophoresis (PFGE), obtaining a suitable size ranges for most sequencing platforms that required high-molecular-weight DNA such as Nanopore or PacBio. Conclusions A high-throughput, fast and inexpensive DNA extraction protocol was developed and validated for a wide variety of plants and tissues. SILEX offers an easy, scalable, efficient and inexpensive way to extract DNA for various next-generation sequencing applications including SPET and Nanopore among others.

(Co0.4Zn0.4Ni0.2Fe2O4)α(SiO2)(100−α) samples obtained by embedding Co0.4Zn0.4Ni0.2Fe2O4 nanoparticles in SiO2 in various proportions were synthesized by sol-gel process and characterized using thermal analysis, Fourier-transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, inductively coupled plasma optical emission spectrometry, and magnetic measurements. Poorly crystalline Co–Zn–Ni ferrite at low annealing temperatures (500 °C) and highly crystalline Co–Zn–Ni ferrite together with traces of crystalline Fe2SiO4 (800 °C) and SiO2 (tridymite and cristobalite) (1200 °C) were obtained. At 1200 °C, large spherical particles with size increasing with the ferrite content (36–120 nm) were obtained. Specific surface area increased with the SiO2 content and decreased with the annealing temperature above 500 °C. Magnetic properties were enhanced with the increase in ferrite content and annealing temperature.

The antibacterial activity of zinc oxide particles has received significant interest worldwide, especially through the implementation of technology to synthesize particles in the nanometer range. This study aimed to determine the antimicrobial efficacy of silica-based iron oxide matrix (SiO2FexOy) synthesized with various amounts of ZnO (SiO2FexOyZnO) against various pathogens. It is observed that, with the addition of ZnO to the system, the average size of the porosity of the material increases, showing increasingly effective antibacterial properties. Zinc-iron-silica oxide matrix composites were synthesized using the sol–gel method. The synthesized materials were investigated physicochemically to highlight their structural properties, through scanning electron microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), and Fourier-transform infrared spectroscopy (FT-IR). At the same time, surface area, pore size and total pore volume were determined for materials synthesized using the Brunauer–Emmett–Teller (BET) method. Although the material with 0.0001 g ZnO (600 m2/g) has the highest specific surface area, the best antimicrobial activity was obtained for the material with 1.0 g ZnO, when the average pore volume is the largest (~8 nm) for a specific surface of 306 m2/g. This indicates that the main role in the antibacterial effect has reactive oxygen species (ROS) generated by the ZnO that are located in the pores of the composite materials. The point of zero charge (pHpZc) is a very important parameter for the characterization of materials that indicate the acid-base behaviour. The pHpZc value varies between 4.9 and 6.3 and is influenced by the amount of ZnO with which the iron-silica oxide matrix is doped. From the antimicrobial studies carried out, it was found that for S. aureus the total antibacterial effect was obtained at the amount of 1.0 g ZnO. For Gram-negative bacteria, a total antibacterial effect was observed in S. flexneri (for the material with 0.1 g ZnO), followed by E. coli (for 1.0 g ZnO). For P. aeruginosa, the maximum inhibition rate obtained for the material with 1.0 g ZnO was approximately 49%.

Resveratrol (RES) is a naturally occurring product with numerous biological activities. Despite its potential benefits, its use is limited due to its low aqueous stability and solubility in its native form. The porous sol–gel silica materials which are able to entrap different organic molecules represent new studied release carriers. The aim of this work was to generate a solid matrix to encapsulate RES ensuring protection, increased solubility and release in solutions. A non-toxic ingredient, namely β-cyclodextrin (β-CD), able to form inclusion complexes (ICs) with RES has been used. Ecological formulations have been processed by entrapping the RES containing ICs in silica matrices obtained from a silica colloidal sol by the aqueous route of the sol–gel method. Characterization methods (DSC, FTIR, UV–Vis, fluorescence studies, SEM) have evidenced the presence of RES–β-CD inclusion complex in the silica powder, RES stability in the matrix and its release in aqueous and organic solutions, and the morphology of the carrier. An evaluation of the antioxidant activity of RES in the present formulation was performed by the chemiluminescence assay and RES release profile in aqueous solutions was obtained by HPLC–MS. The resulted materials can find applications in different domains. [ABSTRACT FROM AUTHOR]

In the present study, stabilizer caged fluorescent rhodamine B mesoporous silica particles with special shapes were prepared. The prepared particles have a pore volume of 1.92 cm3/g and a pore diameter of 12 nm. The abundant hydroxyl functional groups of mesoporous silica are responsible for the superior loading capacity of target molecular specie. The appearance of bands due to –COOH, –CH3, –CH2, –NH etc. indicated that the fluorescent rhodamine B could be encaged with the stabilizer inside the mesoporous channels. The performance of mesostructured origami silica matrix was evaluated by in vitro release experiments. From the in vitro release results, this material is suggested to have appropriate features for almost no release at pH = 1.2 and very slow release at neutral pH value. The same material could be best employed at pH 4.5 and at high pH values. It is concluded that mesostructured origami silica matrix is a smart nano-platform and can be utilized for high retention of cargo molecules. [ABSTRACT FROM AUTHOR]

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This paper presents the results of research on a luminescent dye bound in a silica matrix. The new developed dye from the group of azaheterocyclic compounds was used: 3-(p-hydroxyphenyl)-1-phenyl-1H-pyrazolo [3,4-b]quinoxaline. The structure and composition of the dye was examined by 1HNMR, 13CNMR, FTIR, and elemental analysis. Its absorption and photoluminescence characteristics were tested in solvents of different polarity in UV-Vis range. The films were prepared by sol–gel method and dip-coating technique. The dye was introduced into a sol in the course of a synthesis of the latter. DLS and FTIR measurements of sols were performed. Optical properties were investigated using UV-Vis spectrophotometry and monochromatic ellipsometry. The surface morphology of the layers was examined by atomic force microscopy. Our investigations showed that the dye bound in the silica matrix does not lose its photoluminescent properties. The emission band at λPL = 550 nm (λex = 365 nm) was recorded for the dye in the matrix. The layers are optically homogeneous with smooth surfaces. Dye doped silica films have RMS surface roughness of 2.17 nm over areas of 2 × 2 μm2. The idea of binding a photoluminescent dye in a silica matrix presented in the paper can be applied in the technology of luminescent solar concentrators.

Background: The use of sequencing and genotyping platforms has undergone dramatic improvements, enabling the generation of a wealth of genomic information. Despite this progress, the availability of high-quality genomic DNA (gDNA) in sufficient concentrations is often a main limitation, especially for third-generation sequencing platforms. A variety of DNA extraction methods and commercial kits are available. However, many of these are costly and frequently give either low yield or low-quality DNA, inappropriate for next generation sequencing (NGS) platforms. Here, we describe a fast and inexpensive DNA extraction method (SILEX) applicable to a wide range of plant species and tissues. Results: SILEX is a high-throughput DNA extraction protocol, based on the standard CTAB method with a DNA silica matrix recovery, which allows obtaining NGS-quality high molecular weight genomic plant DNA free of inhibitory compounds. SILEX was compared with a standard CTAB extraction protocol and a common commercial extraction kit in a variety of species, including recalcitrant ones, from different families. In comparison with the other methods, SILEX yielded DNA in higher concentrations and of higher quality. Manual extraction of 48 samples can be done in 96 min by one person at a cost of 0.12 €/sample of reagents and consumables. Hundreds of tomato gDNA samples obtained with either SILEX or the commercial kit were successfully genotyped with Single Primer Enrichment Technology (SPET) with the Illumina HiSeq 2500 platform. Furthermore, DNA extracted from Solanum elaeagnifolium using this protocol was assessed by Pulsed-field gel electrophoresis (PFGE), obtaining a suitable size ranges for most sequencing platforms that required high-molecular-weight DNA such as Nanopore or PacBio. Conclusions: A high-throughput, fast and inexpensive DNA extraction protocol was developed and validated for a wide variety of plants and tissues. SILEX offers an easy, scalable, efficient and inexpensive way to extract DNA for various next-generation sequencing applications including SPET and Nanopore among others. [ABSTRACT FROM AUTHOR]

The effect of SiO2 embedding on the obtaining of single-phase ferrites, as well as on the structure, morphology and magnetic properties of (Zn0.6Mn0.4Fe2O4)δ(SiO2)100−δ (δ = 0–100%) nanoparticles (NPs) synthesized by sol-gel method was assessed. The phase composition and crystallite size were investigated by X-ray diffraction (XRD), the chemical transformations were monitored by Fourier transform infrared (FT-IR) spectroscopy, while the morphology of the NPs by transmission electron microscopy (TEM). The average crystallite size was 5.3–27.0 nm at 400 °C, 13.7–31.1 nm at 700 °C and 33.4–49.1 nm at 1100 °C. The evolution of the saturation magnetization, coercivity and magnetic anisotropy as a function of the crystallite sizes were studied by vibrating sample magnetometry (VSM) technique. As expected, the SiO2 matrix shows diamagnetic behavior accompanied by the accidentally contribution of a small percent of ferromagnetic impurities. The Zn0.6Mn0.4Fe2O4 embedded in SiO2 exhibits superparamagnetic-like behavior, whereas the unembedded Zn0.6Mn0.4Fe2O4 behaves like a high-quality ferrimagnet. The preparation route has a significant effect on the particle sizes, which strongly influences the magnetic behavior of the NPs.

This study reports the preparation and characterization of CuCr2O4/SiO2 and Cu2Cr2O4/SiO2 nanocomposites. In order to obtain 50 mass% CuCr2O4/SiO2 and Cu2Cr2O4/SiO2 nanocomposites, we have used a method based on the thermal decomposition of the precursors Cu(II) and Cr(III) carboxylate type complexes inside the SiO2 matrix. The precursors were formed inside the gels during the redox reaction between Cu(II) and Cr(III) metal nitrates and 1,3-propanediol (1,3PD). As a result of the gels heating, the precursors decomposed at ~ 300 °C leading to the amorphous metal oxides CuO and Cr2O3+x. Cr2O3+x turned to crystalline α-Cr2O3 (crystalline) at 400 °C which subsequently interacted with CuO. Well crystallized Cu2Cr2O4 was obtained at 1000 °C as a result of the interaction between CuCr2O4 and residual CuO formed at 800 °C. In both samples the oxides were homogenously distributed within the amorphous silica matrix. The nanocomposite samples CuCr2O4/SiO2 and Cu2Cr2O4/SiO2 obtained at different annealing temperatures were characterized by thermal analysis, FT-IR spectrometry and powder x-ray diffraction. The results showed that the silica matrix plays a crucial role for the preparation of the desired chromite nanoparticles. [ABSTRACT FROM AUTHOR]

• Acyclovir-silica composites were prepared using sol-gel technology (66). • Interactions in the composites were studied by UV/VIS and FTIR spectroscopy (75). • Effects of synthesis pH and silica modification on the interactions were elucidated (83). Encapsulation of drugs is promising strategy to improve their pharmacological and consumer properties. The functional properties of the encapsulated drug depend on interactions between the drug and capsule material. Antiviral drug acyclovir (ACV) was encapsulated in silica matrixes using sol-gel technology. The effects of synthesis pH and the silica matrix functionalization by organic groups on the drug – silica matrix interaction were studied. The interactions were investigated using UV/VIS spectroscopy and Fourier-transform infrared (FTIR) spectroscopy. The nature of the interactions in the obtained composites was discussed. It was found that the drug self-association in some composites can be provoked by electrostatic repulsion between the drug and the silica matrix. [ABSTRACT FROM AUTHOR]

Abstract: An in situ shape-stabilized phase change material (ssPCM) from polyethylene glycol (PEG) has been produced by sol-gel method. The inorganic matrix was in situ formed from tetraethyl orthosilicate (TEOS), controlling the condensation rate in a second alkaline step using NaOH. ssPCMs having a latent heat up to 113.8 J/g were synthetized using a sol with a molar ratio H2O:EtOH:H2SO4:PEG1000:TEOS of 2:0.34:0.021:0.50:1 and an equivalent ratio NaOH/H2SO4 of 1.15 for promoting the gel step. The presence of high-density hydrogen bonds between silanol groups and the ether oxygen atoms of PEG and the existence of latent heat allowed to confirm that the PEG worked in two ways. It either forms the PEG-SiO2 matrix or adsorbs onto the surface of the previous polymeric matrix, losing or conserving its latent heat, respectively. The addition of NaOH allowed to change the functionality of the silicon matrix which strongly affected the water content, the thermal stability, and the amount of active PEG in the ssPCMs, leading to an optimal neutralization condition when an equivalent ratio NaOH/H2SO4 of 1.15 was used. The obtained ssPCM has an appropriate range of operative temperatures, a high latent heat in the range of common thermoregulating materials, and a proper thermal reliability.An in situ shape-stabilized phase change material from polyethylene glycol has been produced by sol-gel method, studying the effect of the condensation step on its final properties. Sol-gel method was used for the in situ production of a ssPCM from PEG and SiO2.The sol condensation rate was controlled by adding NaOH in the neutralization step.PEG works either by forming the PEG-SiO2 matrix or adsorbing onto this solid as PCM.The SiO2 functionality was established by the neutralization degree.The competition between PEG and SiO- by SiOH groups led to obtain an optimal ssPCM. [ABSTRACT FROM AUTHOR]

Abstract Owing to the pH sensing applications, a mixture of four pH dyes (phenol red, bromophenol blue, creosol red, and phenolphthalein) is encapsulated in mesoporous silica aerogel by sol-gel method. FE-SEM analysis shows that dyes have great influence on the morphology of silica matrix. After encapsulation, silica aerogel matrix has low surface roughness ∼ 1.76 nm, ultra-thin layer 8.26 nm, high surface area of 433 m2/g, high optical transparency 77%, low refractive index ∼1.37 at 550 nm and thermally stable. The sensor response is optimized at pH 1–12 with the high value of pKa ∼8.35 at 565 nm without any leaching traces. The fast response time 0.71s in acidic medium (pH 1) and 0.36 s in basic medium (pH 12) is observed. From experimental findings, it can be concluded that fusion of sol-gel and nano-technologies can thus open a new way to synthesize thermally stable, high quality nano-porous optical material for sensing applications at dynamic pH range. Graphical abstract Image 1 Highlights • Indicator dyes encapsulated mesoporous silica aerogel matrix is synthesized by sol-gel method for pH sensing. • Microscopic analysis shows that indicator dyes has great influence on the morphology of host silica matrix aerogel. • BET analysis confirmed that silica matrix has a high surface area of ∼433 m2/g after dyes encapsulation. • Thermally stable matrix has optical transparency 77 % and low refractive index ~ 1.37 at 550 nm after encapsulation. • The sensor response is optimized at pH 12 with pKa ~ 8.35 value at 565 nm. The fast response time 0.36 s is reported. [ABSTRACT FROM AUTHOR]

Chemical looping hydrogen production (CLHP) is widely regarded as a clean and efficient route for high purity hydrogen production. However, a huge barrier is how to avoid serious deactivation caused by sintering and agglomeration of oxygen carriers. A novel fabrication process of highly dispersing NiFe 2 O 4 into silica matrix is proposed. The oxygen carriers of NiFe 2 O 4 completely dispersed over silica matrix (NFSM) are successfully synthesized. The characterizations, hydrogen production capacity and cycle redox performance of oxygen carriers are further investigated. The results illustrate that NiFe 2 O 4 active components are homogeneously dispersed on the silica matrix without any impurities. NFSM demonstrates the highest reactivity with CO as well as the greatest hydrogen production of 296 mL/g due to the strong confinement effect of silica matrix and good particle dispersion. The porous silica matrix offers large amounts of channels for the lattice oxygen transport and effectively prevents Fe and Ni cations outward migration to particle surface, which actually inhibits the larger clusters and sintering. NFSM can keep stable hydrogen production of approximately 290 mL/g during the cyclic experiments. Briefly, the innovation method of embedding active component into well-established silica matrix supports contributes to the enhanced anti-sintering properties and redox stability of oxygen carriers. [Display omitted] • A novel fabrication method which homogeneously disperse NiFe 2 O 4 active components over silica matrix is proposed. • The confinement effect of silica matrix may play a significant role in promoting resistance to sintering. • Well-established silica networks effectively maintain the morphological structure of NiFe 2 O 4. • An unhampered diffusion of gases and better cycle stability are observed. • The NFSM oxygen carrier possesses splendid resistance to carbon deposition. [ABSTRACT FROM AUTHOR]

The effects of laser irradiation on γ-Fe2O3 4 ± 1 nm diameter maghemite nanocrystals synthesized by co-precipitation and dispersed into an amorphous silica matrix by sol-gel methods have been investigated as function of iron oxide mass fraction. The structural properties of γ-Fe2O3 phase were carefully examined by X-ray diffraction and transmission electron microscopy. It has been shown that γ-Fe2O3 nanocrystals are isolated from each other and uniformly dispersed in silica matrix. The phase stability of maghemite nanocrystals was examined in situ under laser irradiation by Raman spectroscopy and compared with that resulting from heat treatment by X-ray diffraction. It was concluded that ε-Fe2O3 is an intermediate phase between γ-Fe2O3 and α-Fe2O3 and a series of distinct Raman vibrational bands were identified with the ε-Fe2O3 phase. The structural transformation of γ-Fe2O3 into α-Fe2O3 occurs either directly or via ε-Fe2O3, depending on the rate of nanocrystal agglomeration, the concentration of iron oxide in the nanocomposite and the properties of silica matrix. A phase diagram is established as a function of laser power density and concentration.

The aim of this work is the synthesis of antibacterial biomedical implants using sol–gel method. Different percentages (6, 12, 24, 50 wt%) of polyethylene glycol (PEG) or poly(ε‐caprolactone) (PCL) are embedded in the silica matrix; subsequently, high amounts of chlorogenic acid (CGA 20 wt%) are added to SiO2/PEG and SiO2/PCL sol. Fourier transform infrared spectroscopy is used to evaluate the interactions among different organic and inorganic phases in the hybrid materials. Furthermore, in order to study the potential antibacterial properties of the materials, two different bacterial strains are used and the diameter of zone of inhibition is observed. CGA is a natural product that is present in coffee beans, as well as tea leaves, grapes, and apples. This natural molecule is added to sol–gel materials due to its many health‐promoting properties. [ABSTRACT FROM AUTHOR]

Graphical abstract Gold and silver nanoparticle catalyzed reductive dehalogenation of halo acetic acids are investigated both experimentally and theoretically. Highlights • Gold and Silver nanoparticle entrapped in silica matrices have been synthesized. • Reductive dehalogenation of halo acetic acids proceeds via different mechanisms. • Reduction depends on the nature of nanoparticle and the rate of addition of NaBH 4. • DFT calculation and isotopic labeling experiments support the mechanism. Abstract This study investigated the reductive de-halogenations of toxic Br 3 CCO 2 −, Br 2 CHCO 2 −, BrCH 2 CO 2 −, CH 3 CHBrCO 2 −, CH 2 BrCH 2 CO 2 −, CH 2 BrCHBrCO 2 −, Cl 3 CCO 2 −, Cl 2 CHCO 2 - and ClCH 2 CO 2 − by sodium borohydride catalyzed by sol-gel silica entrapped Au0 and Ag0 nanoparticles. The results indicate that the mechanism of reduction of Br 3 CCO 2 − differs from that of Cl 3 CCO 2 −. Calculated by DFT, the source of this difference lies in the larger bond strength of C Cl compared to that of C Br and the weaker M0 C bond strength in Au0-CBr 2 CO 2 − compared to those of Au0-CCl 2 CO 2 − and Au0-CH 2 CO 2 −. Furthermore, the de-halogenation mechanisms catalyzed by Ag0-NPs differ from those catalyzed by Au0-NPs. The latter observation is attributed to the different Ag C and Au C bond strengths and to the different over-potentials for H 2 release of these M0-NPs. In addition, product composition depends on the rate of BH 4 − addition. Proton labeling experiments prove that nearly all the hydrogen atoms in the products originated from the water solvent and not from the BH 4 −. The detailed mechanistic conclusions that can be drawn from these results differ considerably from those commonly accepted for de-halogenation processes. [ABSTRACT FROM AUTHOR]

Highlights • Thermally stable CR immobilization silica matrix is synthesized by sol–gel method for sensing applications. • Microscopic analysis revealed the porous surface with average surface roughness ∼1.98 nm and ultra-thin ∼12 nm thickness. • Synthesized matrix has high surface area of 458 m2/g, high transparency ∼82 % and low refractive index 1.36. • The calculated sensitivity ∼90 (a.u.)/pH at 434 nm and fast response time ∼0.5 s–0.2 s is reported. • Experimental findings shows that the coated matrix has potential for opto-chemical sensing devices. Abstract This research work is concerned with the synthesis of cetyl trimethylammonium bromide (CTAB) assisted silica nanomatrix and creosol red (CR) immobilization in silica nanomatrix. The synthesized nanomatrices are systematically characterized by FESEM/EDS analysis, AFM, FTIR, TGA, BET and UV–vis spectroscopy. FESEM analysis suggests the porous structure network of CTAB assisted silica occupied by CR species after immobilization. Silicon and oxygen signals along with CTAB and CR species by EDS spectra confirm a strong interaction with each other. AFM analysis exhibited the crack-free smooth surface with low average surface roughness ∼2.25 nm which decreased down to ∼1.98 nm. The thickness ∼12 nm is calculated after CR immobilization. FTIR spectroscopy confirmed the presence of silica molecules and CR species bonding after immobilization in silica matrix. BET analysis confirmed the mesoporosity of synthesized matrices with surface area of 458 m2/g, after immobilization. TGA and UV–vis analysis show that thermally stable CR immobilized matrix is 82% transparent and has low refractive index ∼1.38. The proposed sensing device has linear sensitivity ∼90 (a.u.)/pH unit with coefficient of determination (R2) ∼0.98 within pH 1–9. Fast response has been observed at 0.2 s in pH 9 with color change behavior and 98% repeatability identify that the coated matrix has potential in opto-chemical sensing device. [ABSTRACT FROM AUTHOR]

In this work, the self-cleaning and photocatalytic properties of mesoporous TiO2/AuNRs-SiO2 composites (namely UCA-TiO2Au) prepared by a simple and low-cost technique were investigated toward application in building materials. Mesoporous photocatalytic nanocomposites coating the surface of stone and other building materials are a very promising approach to address relevant questions connected with the increasing atmospheric pollution. We tested three types of preformed TiO2/AuNRs nanostructures in order to evaluate the effect of AuNRs on the photocatalytic activity of resulting coatings deposited on the surface of a popular building limestone. The resulting nanocomposites provide crack-free surface coatings on limestone, effective adhesion, improve the stone mechanical properties and impart hydrophobic and self-cleaning properties. Photocatalytic characterization involved the degradation of a target compound (Methylene blue; MB) under direct exposure to simulated solar light using TiO2 P25 Evonik (TiO2 P25) as a reference material. Moreover, these coatings upon irradiation by simulated solar light were successfully employed for the photocatalytic oxidation of carbon soot. The experimental results revealed that UCA-TiO2Au samples are the best performing coating in both MB bleaching and soot degradation. [ABSTRACT FROM AUTHOR]

In this work, we report on the theoretical study of one-dimensional magnetophotonic crystals (MPC) comprising of periodic dielectric structure Si/SiO and of silica matrix doped with cobalt-ferrite (CoFe 2 O 4 ) magnetic nanoparticles as the only magnetic defect layer. Such structure can be prepared by sol-gel dip coating method that controls the thickness of each layer with nanometer level, hence, can overcome the problem of integration of the magneto-optical (MO) devices. We have studied the influence of the volume fraction (concentration of magnetic nanoparticles VF%) on the optical (reflectance, transmittance and absorption) and MO (Kerr rotation) responses in reflection-type one-dimensional MPCs. During investigation of the influence of magnetic nanoparticle’s concentration, we found that giant Kerr rotations (even ≈135° for VF = 39%) can be obtained accompanied by large reflectance and low amounts for transmittance and absorption. We report on the demonstration of large MO quality factor and figure of merit in cobalt-ferrite magnetic nanoparticles in the infrared regime. Given the large Kerr rotation, high reflectance accompanied by low absorption and nearly zero transmittance of the 1D MPC containing cobalt-ferrite magnetic nanoparticles, large MO Q factor and figure of merit are obtained. [ABSTRACT FROM AUTHOR]

The biocompatible silica precursor tetrakis(2-hydroxyethyl)orthosilicate with ethylene glycol residues was used instead of the common alcohol-containing tetraethoxysilane for the first time to prepare a biorecognition element by entrapping the marine microalga Porphyridium purpureum into a silica matrix by a one-stage sol-gel procedure at conditions (pH, ionic strength, and temperature) appropriate for living cells. We show that the microalga immobilized in this way fully maintains its viability and functionality. We furthermore show that the silica matrix had a stabilizing effect, providing microalgal survival and functionality at increased temperature. The high optical transparency of the silica matrix allowed us to study the optical properties of Porphyridium purpureum thoroughly. When irradiated by a laser, intense fluorescence of chlorophyll- a and phycoerythrin of the photosynthetic system was observed. The characteristics of this fluorescence differed notably from that observed with P. purpureum in suspension before immobilization; possible reasons for this and an underlying mechanism are discussed. [ABSTRACT FROM AUTHOR]