Self-assembly preparation of Zn2+ -immobilized silica hybrid monolith and application in solid-phase micro-extraction of ß-agonists.

Exploiting adsorbents with highly efficient extraction performance is of great promise for extracting small organic molecules from biological samples. In this work, a novel Zn2+ -immobilized chitosan@silica hybrid monolith was prepared through a simple self-assembly Zn2+ -immobilization process. Exploited as an adsorbent in solid-phase micro-extraction for extracting trace ß-agonists, the monolith exhibited high extraction efficiencies for salbutamol, clenbuterol, and ractopamine with the enrichment factors approaching 120, 85, and 52, respectively. These could be attributed to the effective interaction between Zn2+ ions and the target molecule via coordination or other intermolecular interactions. Under optimized extraction operations, a sensitive determination was successfully developed coupling with high-performance liquid chromatography-ultraviolet detection. The linear range was 0.17-58.8, 0.12-68.5, and 0.18-65.5 ng/ml for salbutamol, clenbuterol, and ractopamine. The limits of detection of the ß-agonists were from 0.04 to 0.07 ng/ml, and the limits of quantification were from 0.12 to 0.18 ng/ml. The recoveries of spiking in mutton samples were observed in the range of 85.9%-95.7%, with relative standard deviations <8.0% (n = 3). Application tests demonstrated this newly developed determination was practical, accurate, and convenient for detecting trace content ß-agonists in meat.

Hybrid Materials Based on Silica Matrices Impregnated with Pt-Porphyrin or PtNPs Destined for CO2 Gas Detection or for Wastewaters Color Removal.

Multifunctional hybrid materials with applications in gas sensing or dye removal from wastewaters were obtained by incorporation into silica matrices of either Pt(II)-5,10,15,20-tetra-(4-allyloxy-phenyl)-porphyrin (PtTAOPP) or platinum nanoparticles (PtNPs) alone or accompanied by 5,10,15,20-tetra-(4-allyloxy-phenyl)-porphyrin (TAOPP). The tetraethylorthosilicate (TEOS)-based silica matrices were obtained by using the sol-gel method performed in two step acid-base catalysis. Optical, structural and morphological properties of the hybrid materials were determined and compared by UV-vis, fluorescence and FT-IR spectroscopy techniques, by atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM) and by Brunauer-Emmett-Teller (BET) analysis. PtTAOPP-silica hybrid was the most efficient material both for CO2 adsorption (0.025 mol/g) and for methylene blue adsorption (7.26 mg/g) from wastewaters. These results were expected due to both the ink-bottle mesopores having large necks that exist in this hybrid material and to the presence of the porphyrin moiety that facilitates chemical interactions with either CO2 gas or the dye molecule. Kinetic studies concerning the mechanism of dye adsorption demonstrated a second order kinetic model, thus it might be attributed to both physical and chemical processes.

A Dual Ligand Sol⁻Gel Organic-Silica Hybrid Monolithic Capillary for In-Tube SPME-MS/MS to Determine Amino Acids in Plasma Samples.

This work describes the direct coupling of the in-tube solid-phase microextraction (in-tube SPME) technique to a tandem mass spectrometry system (MS/MS) to determine amino acids (AA) and neurotransmitters (NT) (alanine, serine, isoleucine, leucine, aspartic acid, glutamic acid, lysine, methionine, tyrosine, and tryptophan) in plasma samples from schizophrenic patients. An innovative organic-silica hybrid monolithic capillary with bifunctional groups (amino and cyano) was developed and evaluated as an extraction device for in-tube SPME. The morphological and structural aspects of the monolithic phase were evaluated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), nitrogen sorption experiments, X-ray diffraction (XRD) analyses, and adsorption experiments. In-tube SPME-MS/MS conditions were established to remove matrix, enrich analytes (monolithic capillary) and improve the sensitivity of the MS/MS system. The proposed method was linear from 45 to 360 ng mL-1 for alanine, from 15 to 300 ng mL-1 for leucine and isoleucine, from 12 to 102 ng mL-1 for methionine, from 10 to 102 ng mL-1 for tyrosine, from 9 to 96 ng mL-1 for tryptophan, from 12 to 210 ng mL-1 for serine, from 12 to 90 ng mL-1 for glutamic acid, from 12 to 102 ng mL-1 for lysine, and from 6 to 36 ng mL-1 for aspartic acid. The precision of intra-assays and inter-assays presented CV values ranged from 1.6% to 14.0%. The accuracy of intra-assays and inter-assays presented RSE values from -11.0% to 13.8%, with the exception of the lower limit of quantification (LLOQ) values. The in-tube SPME-MS/MS method was successfully applied to determine the target AA and NT in plasma samples from schizophrenic patients.

Preparation of a hybrid monolithic stationary phase with allylsulfonate for the rapid and simultaneous separation of cations in capillary ion chromatography.

A hybrid monolithic column with sulfonate functionality was successfully prepared for the simultaneous separation of common inorganic cations in ion-exchange chromatographic mode through a simple and easy single-step preparation method. The strong cation-exchange moieties were provided directly from allylsulfonate, which worked as an organic monomer in the single-step reaction. Inorganic cations (Li(+), Na(+), K(+), NH4(+), Cs(+), Rb(+), Mg(2+), Ca(2+), and Sr(2+)) were separated satisfactorily by using CuSO4 as the eluent with indirect UV detection. The allysulfonate hybrid monolith showed a better performance in terms of speed and pressure drop than the capillary packed column. The number of theoretical plates achieved was 19,017 plates/m (in the case of NH4(+) as the analyte). The relative standard deviations (n = 6) of both retention time and peak height were less than 1.96% for all the analyte cations. The allysulfonate hybrid monolithic column was successfully applied for the rapid and simultaneous separation of inorganic cations in groundwater and the effluent of onsite domestic wastewater treatment system.

Histidine-modified organic-silica hybrid monolithic column for mixed-mode per aqueous and ion-exchange capillary electrochromatography.

A novel organic-silica hybrid monolith was prepared through the binding of histidine onto the surface of monolithic matrix for mixed-mode per aqueous and ion-exchange capillary electrochromatography. The imidazolium and amino groups on the surface of the monolithic stationary phase were used to generate an anodic electro-osmotic flow as well as to provide electrostatic interaction sites for the charged compounds at low pH. Typical per aqueous chromatographic behavior was observed in water-rich mobile phases. Various polar and hydrophilic analytes were selected to evaluate the characteristics and chromatographic performance of the obtained monolith. Under per aqueous conditions, the mixed-mode mechanism of hydrophobic and ion-exchange interactions was observed and the resultant monolithic column proved to be very versatile for the efficient separations of these polar and hydrophilic compounds (including amides, nucleosides and nucleotide bases, benzoic acid derivatives, and amino acids) in highly aqueous mobile phases. The successful applications suggested that the histidine-modified organic-silica hybrid monolithic column could offer a wide range of retention behaviors and flexible selectivities toward polar and hydrophilic compounds.

Organic-silica hybrid monolithic sorbents for sample preparation techniques: A review on advances in synthesis, characterization, and applications.

Organic-silica hybrid monolithic materials have attracted considerable attention as potential stationary phases in separation science. These materials combine the advantages of organic polymer and silica-based monoliths, including easy preparation, lower back pressure, high permeability, excellent mechanical strength, thermal stability, and tunable surface chemistry with high surface area and selectivity. The outstanding chromatographic efficiency as stationary phase of hybrid monolithic capillary columns for capillary liquid chromatography and capillary electrochromatography has been reported in many papers. Organic-silica hybrid monolithic materials have also been extensively used in the field of sample preparation. Owing to their surface functionalities, these porous sorbents offer unique selectivity for pre-concentration of different analytes in the most complex matrixes by fast dynamic transport. These sorbents not only improve the analytical method sensitivity, but also introduce novelties in terms of extraction devices and instrument coupling strategies. The current review covers the period spanning from 2017 to 2023 and describes the properties of organic-inorganic hybrid monolithic materials, the present status of this technology and summarizes recent developments in their use as innovative sorbents for microextraction sample preparation techniques (solid phase microextraction with pipette tip, offline in-tube SPME, in-tube SPME online with LC, and in-tube SPME directly coupled with mass spectrometry). Aspects such as the synthesis methods (sol-gel process, one-pot approach, and polyhedral oligomeric silsesquioxanes-based procedure), characterization techniques, and strategies to improve extraction efficiency in various applications in different areas (environmental, food, bioanalysis, and proteomics) are also discussed.

Density and porosity analyses of porous hybrid microparticles containing gas in closed pores using centrifugal liquid sedimentation-dynamic light scattering combined analytical method.

Porous hybrid microparticles are characterized by their densities and porosities. Consequently, the evaluation for density and porosity of porous hybrid microparticles in liquids is crucial for predicting the transport of particles in the atmosphere, human body, and industrial processes. However, direct measurement of the density and porosity of porous hybrid microparticles in liquids remains a challenge. In this study, we investigated the centrifugal sedimentation of polystyrene-silica hybrid microparticles with and without gas-containing closed pores. A centrifugal liquid sedimentation-dynamic light scattering combined analytical method was employed to determine the apparent densities of hybrid microparticles with and without gas-containing closed pores. The porosity of the hybrid microparticles with gas-containing closed pores was elucidated based on the inner buoyancy, which is a centrifugal force generated by the presence of low-density gas inside numerous closed pores. Further, the inner gas buoyancy was analyzed to estimate the particle porosity in liquids. The results obtained in this study confirmed the feasibility of utilizing the proposed method to determine the apparent density and porosity of porous hybrid microparticles in liquids.

Optimized Sulfonated Poly(Ether Ether Ketone) Membranes for In-House Produced Small-Sized Vanadium Redox Flow Battery Set-Up.

The ionic exchange membranes represent a core component of redox flow batteries. Their features strongly affect the performance, durability, cost, and efficiency of these energy systems. Herein, the operating conditions of a lab-scale single-cell vanadium flow battery (VRFB) were optimized in terms of membrane physicochemical features and electrolyte composition, as a way to translate such conditions into a large-scale five-cell VRFB stack system. The effects of the sulfonation degree (SD) and the presence of a filler on the performances of sulfonated poly(ether ether ketone) (SPEEK) ion-selective membranes were investigated, using the commercial perfluorosulfonic-acid Nafion 115 membrane as a reference. Furthermore, the effect of a chloride-based electrolyte was evaluated by comparing it to the commonly used standard sulfuric acid electrolyte. Among the investigated membranes, the readily available SPEEK50-0 (SD = 50%; filler = 0%) resulted in it being permeable and selective to vanadium. Improved coulombic efficiency (93.4%) compared to that of Nafion 115 (88.9%) was achieved when SPEEK50-0, in combination with an optimized chloride-based electrolyte, was employed in a single-cell VRFB at a current density of 20 mA·cm-2. The optimized conditions were successfully applied for the construction of a five-cell VRFB stack system, exhibiting a satisfactory coulombic efficiency of 94.5%.

BMP2-Mediated Silica Deposition: An Effective Strategy for Bone Mineralization.

The combined use of an osteogenic factor, such as bone morphogenetic protein 2 (BMP2), with a bone scaffold was quite functional for the reconstruction of bone defects. Although many studies using BMP2 have been done, there is still a need to develop an efficient way to apply BMP2 in the bone scaffold. Here, we reported an interesting fact that BMP2 has a silica deposition ability in the presence of silicic acid and proposed that such an ability of BMP2 can effectively immobilize and transport itself by a kind of coprecipitation of BMP2 with a silica matrix. The presence of BMP2 in the resulting silica was proved by SEM and EDS and was visualized by FITC-labeled BMP2. The delivery efficacy of BMP2 of silica-entrapped BMP2 on osteoblast differentiation and mineralization using MC3T3 E1 preosteoblast cells was evaluated in vitro. The coprecipitated BMP2 with silica exhibited osteogenesis at a low concentration that was insufficient to give an osteoinductive signal as the free form. Expectedly, the silica-entrapped BMP2 exhibited thermal stability over free BMP2. When applied to bone graft substitution, e.g., hydroxyapatite granules (HA), silica-entrapped BMP 2 laden HA (BMP2@Si/HA) showed sustained BMP2 release, whereas free BMP2 adsorbed HA by a simple dipping method (BMP2/HA) displayed a burst release of BMP2 at an initial time. In the rat critical-size calvarial defect model, BMP2@Si/HA showed better bone regeneration than BMP2/HA by about 10%. The BMP2/silica hybrid deposited on a carrier surface via BMP2-mediated silica precipitation demonstrated an increase in the loading efficiency, a decrease in the burst release of BMP2, and an increase in bone regeneration. Taken together, the coprecipitated BMP2 with a silica matrix has the advantages of not only being able to immobilize BMP2 efficiently without compromising its function but also serving as a stable carrier for BMP2 delivery.

Optical fiber relative humidity sensor based on a FBG with a di-ureasil coating.

In this work we proposed a relative humidity (RH) sensor based on a Bragg grating written in an optical fiber, associated with a coating of organo-silica hybrid material prepared by the sol-gel method. The organo-silica-based coating has a strong adhesion to the optical fiber and its expansion is reversibly affected by the change in the RH values (15.0-95.0%) of the surrounding environment, allowing an increased sensitivity (22.2 pm/%RH) and durability due to the presence of a siliceous-based inorganic component. The developed sensor was tested in a real structure health monitoring essay, in which the RH inside two concrete blocks with different porosity values was measured over 1 year. The results demonstrated the potential of the proposed optical sensor in the monitoring of civil engineering structures.

Synthesis of ionic liquid-bonded organic-silica hybrid monolithic column for capillary electrochromatography.

An ionic liquid (IL) was introduced into the organic-silica hybrid monolithic column as the stationary phase for capillary electrochromatography (CEC). The monolithic silica matrix containing chloropropyl functional group was prepared by the in situ co-condensation of tetramethoxysilane and (3-chloropropyl)-trimethoxysilane via a sol-gel process and chemical modification with N-methylimidazole. The electroosmotic flow of the IL-modified hybrid monolithic column was reversed at acidic pH and the morphology of the column was characterized by scanning electron microscope. Four aromatic hydrocarbons were completely separated with 40% acetonitrile phosphate buffer as the mobile phase and seven inorganic ions were efficiently separated with the phosphate buffer on the column in CEC. Reproducibilities of migration time for four aromatic hydrocarbons (benzene, naphthalene, anthracene, chrysene) were acceptable on IL-modified hybrid monolithic columns. Relative standard deviations of run-to-run (n=5), peak area-to-peak area (n=5), day-to-day (n=3) and column-to-column (n=3) were in the range of 0.72-0.88, 1.47-5.40, 2.44-4.99 and 3.01-8.11%, respectively.

"One-pot" preparation of basic amino acid-silica hybrid monolithic column for capillary electrochromatography.

A novel "one-pot" strategy was developed for the preparation of amino acid (AA)-silica hybrid monolithic column. The basic AA (L-Arginine, L-Lysine and L-Histidine) was covalently incorporated into the silica hybrid skeleton via the epoxy ring-opening reaction between the amine group and the glycidyl moiety in γ-glycidoxypropyltrimethoxysilane (GPTMS), which was confirmed by elemental analysis and FT-IR studies, while the basic AA was also found to catalyze the polycondensation of tetramethoxysilane and GPTMS. The average mesopore and macropore sizes of the prepared basic AA-silica hybrid monolithic columns were 3.86 nm and 1.71 µm for the L-Lysine-silica hybrid monolith, 5.38 nm and 4.24 µm for the L-Arginine-silica hybrid monolith, and 6.38 nm and 1.24 µm for the L-Histidine-silica hybrid monolith. The hybrid monolith afforded a zwitterionic stationary phase for CEC, the direction and magnitude of EOF can be controlled by the pH of the mobile phase used. Besides an electrophoretic mechanism, the monoliths behave in a typical hydrophilic interaction with the analytes when ACN percentage in the mobile phase is over 40%. Four polar compounds (toluene, DMF, formamide and thiourea) were tested on the three AA-silica hybrid monolithic columns, and the best separation efficiency was observed in the L-Lysine-silica hybrid monolithic column, its theoretical plate height was down to 5.7 µm for thiourea when 20 mM HCOOH-HCOONH4 containing 20% ACN (pH 4.1) was used as a running buffer. The corresponding theoretical plate number for toluene, DMF, formamide and thiourea were 123,385, 103,620, 121,845 and 105,345 plates/m, respectively. Effective separation of phenols and peptides on the L-Lysine-silica hybrid monolithic column was achieved using CEC. We believe that this strategy paves a way for the easy preparation of various functional silica hybrid monolithic columns, aiming at different separation purposes.

Preparation and Characterization of New Sol-Gel Hybrid Inulin-TEOS Adsorbent.

A new biopolymer-silica hybrid material consisting of inulin and tetraethoxysilane (TEOS) for use as an adsorbent was successfully synthesized via the sol-gel method in acidic conditions. The hydrolysis and condensation processes were attained in water/ethanol solution. Three molar ratios of inulin:TEOS (1:1, 1:2, and 2:1) were prepared and dried at various temperatures (50, 60, and 70 °C). The optimized molar ratio of 2:1 with a drying temperature of 70 °C was found to obtain the best morphology and characteristics for absorbent properties. Fourier transform infrared spectroscopy (FTIR) analysis showed a strong interaction between inulin and TEOS, which was also observed using energy dispersive X-ray spectroscopy (EDX). Field emission scanning electron microscopy (FESEM) images revealed the presence of nanoparticles on the rough surface of the hybrid sol-gel. X-ray diffractometer (XRD) analysis showed the amorphous state of the silica network where the inulin existed as an anhydrous crystalline phase. Brunauer-Emmet-Teller (BET) analysis confirmed that the composite was mesoporous, with 17.69 m2/g surface area and 34.06 Å pore size. According to thermogravimetric analysis (TGA) results, the hybrid inulin-TEOS adsorbent was thermally stable under a temperature of 200 °C.

In-tube solid phase microextraction and determination of ractopamine in pork muscle samples using amide group modified polysaccharide-silica hybrid monolith as sorbent prior to HPLC analysis.

A facile in-tube solid phase microextraction (in-tube SPME) procedure was developed to enrich ractopamine before HPLC-UV analysis. This was achieved by employing amide groups modified polysaccharide-silica hybrid monolith as an efficient sorbent. The monolith was synthesized by a simple reaction with agarose oxide and tetramethoxylisane, followed by the modification of amide groups via subsequent ring opening, "thiol-ene" click and dehydration reactions. Under the optimized extraction conditions, the enrichment factors for ractopamine, dopamine, clenbuterol, para-methylphenol and phenol were determined to be 50.5, 32.2, 4.8, 2.1 and 1.8, respectively. The monolithic column has ideal selectivity for ractopamine. Coupled with HPLC-UV, this method demonstrated a linearity within 2.0-800 ng/g for ractopamine with spiking in pork muscles (R2 = 0.9958). The LOD was 0.64 ng/g (S/N = 3) and recoveries ranged from 85.2 to 108.1% (n = 3). This approach provides a feasible way for analysis of trace ractopamine in biological samples.

Effect of PMMA/Silica Hybrid Particles on Interfacial Adhesion and Crystallization Properties of Poly(lactic acid)/Block Acrylic Elastomer Composites.

Poly(lactic acid) (PLA) is a relatively brittle polymer, and its low melt strength, ductility, and thermal stability limit its use in various industrial applications. This study aimed to investigate the effect of poly(methyl methacrylate) (PMMA) and PMMA/silica hybrid particles on the mechanical properties, interfacial adhesion, and crystallization behavior of PLA/block acrylic elastomer. PLA/block acrylic elastomer blends exhibit improved flexibility; however, phase separation occurs between PLA and block acrylic elastomer domains. Valid time-temperature superposition (TTS) measurements of viscoelastic behavior were obtained and exhibited interfacial adhesion with the addition of PMMA or PMMA/silica in PLA/block acrylic elastomer blends. In particular, the phase separation temperature was increased by the incorporation of PMMA/silica hybrid particles, which suggests a potential role for these particles in improving the phase stability. In addition, PMMA inhibits crystallization, while PMMA/silica acts as a nucleating agent, thus increasing the crystallization rate and crystallinity degree.

Determination of l-norvaline and l-tryptophan in dietary supplements by nano-LC using an O-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine-silica hybrid monolithic column.

An analytical methodology based on an O-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine (MQD)-silica hybrid monolithic column was developed for the enantioseparation of 9-fluorenylmethoxycarbonyl (FMOC) derivatized amino acids by nano-liquid chromatography. The mobile phase was optimized including the apparent pH, content of ACN, and concentration of the buffer to obtain a satisfactory enantioresolution performance. 27 FMOC derivatized amino acids including 19 protein and 8 non-protein amino acids were tested, and 19 out of them were enantiomerically discriminated obtaining baseline separation for 11 of them. Analytical characteristics of the method were evaluated for norvaline and tryptophan in terms of linearity, precision, accuracy, limits of detection (LOD) and quantitation (LOQ) showing good performance to be applied to the enantiomeric determination of these amino acids in dietary supplements. LOD and LOQ values were 9.3 and 31 µM for norvaline enantiomers and 7.5 and 25 µM for tryptophan enantiomers, respectively. The contents of d-norvaline and d-tryptophan were below their respective LODs in all the analyzed samples. Quantitation of l-tryptophan and l-norvaline showed good agreement with the labeled contents except for one sample which did not show presence of l-norvaline, contrary to the label indication.

Formulating octyl methoxycinnamate in hybrid lipid-silica nanoparticles: An innovative approach for UV skin protection.

Sunscreens have been employed on daily skin care for centuries. Their role in protecting the skin from sun damage, avoiding accelerated photoaging and even limiting the risk of development of skin cancer is unquestionable. Although several chemical and physical filters are approved as sunscreens for human use, their safety profile is dependent on their concentration in the formulation which governs their acceptance by the regulatory agencies. A strategic delivery of such molecules should provide a UV protection and limit the skin penetration. Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) may offer an alternative approach to achieve a synergistic effect on the UV protection when loaded with sunscreens as particles themselves also have a UV light scattering effect. Besides, the lipid character of SLN and NLC improves the encapsulation of lipophilic compounds, with enhanced loading capacity. Silica nanoparticles have also been employed in sunscreen formulations. Due to the formed sol-gel complexes, which covalently entrap sunscreen molecules, a controlled release is also achieved. In the present work, we have developed a new sunscreen formulation composed of hybrid SLN-Silica particles loaded with octyl methoxycinnamate (Parsol®MCX), and their further incorporation into a hydrogel for skin administration. Hybrid SLN-silica particles of 210.0 ± 3.341 nm of mean size, polydispersity below 0.3, zeta potential of ca. |7| mV, loading capacity of 19.9% and encapsulation efficiency of 98.3% have been produced. Despite the slight negative surface charge, the developed hybrid nanoparticles remained physicochemically stable over the study period. Turbiscan transmission profiles confirmed the colloidal stability of the formulations under stress conditions. The texture profile analysis of Parsol-SLN and Parsol-SLN-Si revealed semi-solid properties (e.g. adhesiveness, hardness, cohesiveness, springiness, gumminess, chewiness, resilience) suitable for topical application, together with the bioadhesiveness in the skin of pig ears. The non-irritation profile of the hybrid nanoparticles before and after dispersion into Carbopol hydrogels was confirmed by HET-CAM test.

PMMA-silica nanocomposite coating: Effective corrosion protection and biocompatibility for a Ti6Al4V alloy.

Ti6Al4V is the mostly applied metallic alloy for orthopedic and dental implants, however, its lack of osseointegration and poor long-term corrosion resistance often leads to a secondary surgical intervention, recovery delay and toxicity to the surrounding tissue. As a potential solution of these issues poly(methyl methacrylate)-silicon dioxide (PMMA-silica) coatings have been applied on a Ti6Al4V alloy to act simultaneously as an anticorrosive barrier and bioactive film. The nanocomposite, composed of PMMA covalently bonded to the silica phase through 3-(trimethoxysilyl)propyl methacrylate (MPTS), has been synthesized combining the sol-gel process with radical polymerization of methyl methacrylate. The 5 µm thick coatings deposited on Ti6Al4V have a smooth surface, are homogeneous, transparent, free of pores and cracks, and show a strong adhesion to the metallic substrate (11.6 MPa). Electrochemical impedance spectroscopy results proved an excellent anticorrosive performance of the coating, with an impedance modulus of 26 GΩ cm2 and long-term durability in simulated body fluid (SBF) solution. Moreover, after 21 days of immersion in SBF, the PMMA-silica coating presented apatite crystal deposits, which suggests in vivo bone bioactivity. This was confirmed by biological characterization showing enhanced osteoblast proliferation, explained by the increased surface free energy and protein adsorption. The obtained results suggest that PMMA-silica hybrids can act in a dual role as efficient anticorrosive and bioactive coating for Ti6Al4V alloys.

New chitosan/silica/zinc oxide nanocomposite as adsorbent for dye removal.

Chitosan/silica hybrid was used for zinc oxide (ZnO) nanoparticles immobilization to form chitosan/silica/ZnO nanocomposite. This nanocomposite was utilized to eliminate methylene blue (MB) from wastewater. The effect of ZnO immobilization on the adsorption properties of the nanocomposite was studied in details. The best interpretation for the equilibrium data was given by Langmuir isotherm, and the highest adsorption capacity of MB reached to 293.3 mg/g in slight basic medium. As an effective and low-cost adsorbent, chitosan/silica/ZnO nanocomposite is expected to have a promising future for adsorption of organic dyes from their aqueous solutions.

Study of potential biomedical application of sol-gel derived Zn-doped SiO2-hydroxypropyl cellulose nanohybrids.

A series of Zn-doped hybrid materials based on silica from tetraethoxysilane (TEOS) and hydroxypropyl cellulose (HPC) were prepared by a sol-gel route. The structure, morphology and thermal behavior of synthesized hybrids were characterized by infrared (IR) spectroscopy, ultraviolet-visible spectroscopy (UV-Vis), transmission electron microscopy (TEM) and differential thermal analysis with thermogravimetric analysis (DTA/TG). The obtained materials were investigated for a potential biomedical application. The antibacterial properties of hybrids were investigated by measuring the inhibition zones formed around the materials containing different zinc content in presence of reference strains of Gram-positive and Gram-negative bacteria. The biocompatibility tests showed no cytotoxicity and genotoxicity, as well as no changes in actin cytoskeleton organization for hybrids with Zn content below 5 wt%.