Different Amounts Of TiO2 Research Articles

Synthesis and characterization of montmorillonite/ciprofloxacin/TiO2 porous structure for controlled drug release of ciprofloxacin tablet with oral administration

Bio-nanocomposite materials based on montmorillonite clay and TiO2 were arranged as controlled drug delivery system for oral administration of ciprofloxacin (CPx). For this purpose, minimum amount of the commercial CPx was selected and the extension of the release period from the prepared porous structure was provided. In order to identify the MMT amount used in drug delivery process, adsorption of CPx on MMT was performed in batch system. 0.1 g MMT was found enough to adsorb 250 mg CPx with 99.2% adsorption efficiency. CPx adsorption was best described by Temkin isotherm model (R2 = 0.96) among the other models, which indicated that the linear reduction of adsorption heat. The synthesized MMT/CPx nanocomposites, which include 0.1 g MMT, were coated with different amounts of TiO2 (10–100% wt%) to obtain MMT/CPx/TiO2 porous structure. MMT/CPx/TiO2 (10%) nanocomposite reached 100% release in 24 h in simulated gastric fluid, while MMT/CPx and commercial CPx completed the release in 15 h and 8 h in gastric fluid, respectively. The longest CPx release time in simulated blood fluid was achieved for MMT/CPx/TiO2 (30%) in 69 h. Electrostatic attractions between CPx molecule and the structure were the main reason affecting the drug delivery mechanism. Zeta potential measurements, FTIR and XRD results were also supported the experimental data. CPx release profile fitted well with Korsmeyer-Peppas kinetic model and n value was found higher than 0.89, which indicates Super Case II release mechanism.

Development and characterization of form‐stable porous TiO 2 /tetradecanoic acid based composite PCM with long‐term stability as solar thermal energy storage material

The present study focused on the preparation of form-stable composites of 1-tetradecanoic acid (TDA)/titanium dioxide (TiO2) powder via a facile impregnation method. The use of powdered TiO2 as porous material and thermal conductivity enhancer for TDA is a novel attempt. The morphological, chemical, and crystalline properties of form-stable composite PCMs (Fs-CPCMs), containing different amounts of TiO2, were characterized using field emission scanning electron microscope, Fourier transform infrared spectroscopy, and X-ray diffraction techniques. The finding supports that the produced composites were chemically and structurally stable. The latent heat storage (LHS) properties of composites were obtained from differential scanning calorimeter instrument, and the findings revealed that the Fs-CPCM with 50 mass% TDA has a melting temperature of 52.04°C and a considerably good LHS capacity of 97.75 J/g. The thermal conductivity of TDA was increased remarkably by the addition of TiO2 micro particles. The results obtained from thermogravimetric analysis and thermal cycling test exhibited that the Fs-CPCM, containing 50 mass% TiO2, possesses great thermal degradation durability, cycling chemical stability, and thermal reliability. This composite PCM can be very well used for passive thermal management of electronic devices, automotive components, photovoltaic thermal hybrid designs, solar air/water heating systems, etc.

Removal of cimetidine, ketoprofen and naproxen by heterogeneous catalytic ozonation over volcanic sand at low pH

This work presents experimental results on the catalytic effect of volcanic sand on the simultaneous removal of naproxen, ketoprofen, and cimetidine by ozonation. Catalyst characterization included XRD, EDX, XRF, SEM and physisorption analysis. Removal assays at laboratory scale in a semi-batch reactor showed enhanced removal by the presence of the catalyst at pH 4, but no difference was found at higher pH values. Furthermore, the immobilization of different amounts of TiO2 (2.5 % and 5.0 %) on the sand surface revealed that TiO2 exerted an adverse effect on the catalytic activity at pH 4, lowering ketoprofen removal by up to 41.3 %. Likewise, the highest and fastest removal at pH 4 was obtained using a catalyst dose of 1 g/L and dosing ozone at 15 mg/L (72.5 % ketoprofen; 90.7 % total pharmaceuticals), reaching more than 80 % total elimination after only one minute of treatment. Catalyst reusability evaluated over 5 cycles demonstrated efficient elimination of the pharmaceuticals, with only slight decrease in ketoprofen elimination. Finally, heterogeneous catalytic ozonation of ketoprofen was applied in a real wastewater matrix, obtaining a removal of 75.9 % after 40 min of reaction; this represents a similar efficiency to that achieved in synthetic wastewater.

TiO2–ZnO/Ni–5wt.%Al composite coatings on GH4169 superalloys by atmospheric plasma spray techniques and theirs elevated-temperature tribological behavior

Ni–based composite coatings with different amounts of TiO2–ZnO were fabricated by atmospheric plasma spraying (APS) to protect GH4169 superalloy substrates against excess wear and friction at elevated temperatures. In addition, the influence of the simultaneous addition of the oxides on the microstructure, microhardness, and wear behaviour was investigated. According to the results, the simultaneous addition of TiO2/ZnO provides anti-friction and wear inhibition over 600 °C. In particular at 800 °C, the TiO2–ZnO/Ni–5wt.%Al composite coating (10 wt% TiO2 and 10 wt% ZnO were incorporated within Ni–5wt.%Al matrix) exhibits a superior lubricity and wear resistance compared to the Ni–5wt.%Al based coatings. The XRD, Raman, and TEM characterisations reveal the formation of a glaze oxide layer consisting of NiO, TiO2, ZnO and the in-situ production of ternary oxide (Zn2TiO4), which was primarily responsible for the tribological performance of the sliding wear contacts at the specific temperature.

Facile synthesis of heterojunction of MXenes/TiO2 nanoparticles towards enhanced hexavalent chromium removal

Increasing the surface area and active sites of adsorbent for hexavalent chromium removal in water is considered an effective and efficient way to enhance reduction and adsorption performance. Here 2D/0D heterojunction of Ti3C2 MXenes/TiO2 nanoparticles with different amounts of TiO2 were synthesized using a one-step hydrothermal method and the reduction and adsorption of Cr (VI) at different pH values of composite material were analyzed. The results show that the Ti3C2/TiO2 composite material allows significantly enhanced removal ability of toxic Cr (VI) in water, compared to pure Ti3C2 nanosheets. The effective removal of Cr (VI) in water was 99.35%. The Ti3C2/TiO2 composite can not only rapidly and efficiently remove Cr (VI) from potassium dichromate solution by reducing Cr (VI) to Cr (III), but simultaneously adsorbs the reduced Cr (III). Therefore, the 2D/0D heterojunction of Ti3C2 MXenes/TiO2 nanoparticles has potential application prospects in the reduction adsorption of Cr (VI).

Effect of TiO2 doping on densification and mechanical properties of hydroxyapatite by microwave sintering

Abstract Hydroxyapatite (HAP) possesses excellent bioactivity/osteointegration properties. Nevertheless, its inferior flexural strength and fracture toughness limit its use in human weight-bearing parts. We investigated a microwave sintering technology which can be effectively used to develop titanium dioxide-hydroxyapatite (TiO2-HAP) ceramics with different amounts of TiO2 (0.8,1.6,2.4,3.2,4.0,4.8,5.6 and 6.4 wt%), which contribute to extremely high flexural strength (90–130 MPa) along with a good combination of elastic modulus and fracture toughness. The results of the Rietveld refinement show that multiphase bioceramics (HAP, β-TCP) can be achieved by doping nano-TiO2 under microwave sintering. Despite the fact that the main phases of the sintered TiO2-HAP ceramics are HAP and β-TCP, X-ray diffraction confirms the formation of the CaTiO3 and CaTi2O4(OH)2 phases. Furthermore, the sintering reactions to form these phases are discussed and the results show that an appropriate amount of nano-TiO2 can not only effectively inhibit the growth of grain, but also change the fracture mode and increase the relative density. Finally, it is found that doping nano-TiO2 by microwave heating is an effective technique for producing HAP/β-TCP composite load-bearing implants in clinical applications without coarsening the size of grain.

Antifouling behaviour of PVDF/TiO2 composite membrane: a quantitative and qualitative assessment

The composite membranes of PVDF/TiO2 were prepared by a phase-inversion technique. Different amounts of TiO2 with respect to the weight of the polymer were incorporated in the casting solution to study qualitatively and quantitatively the antifouling property of the membrane. The membrane morphology was studied using a high-resolution scanning electron microscopy and atomic force microscopy, whereas the crystalline nature was studied using X-ray diffraction method. The interfacial interactions between foulants and TiO2 immobilized membranes were also evaluated using the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) approach. The XDLVO theory revealed an increase in repulsive interactive energy barrier with an increase in TiO2 loading, thus causing to improve the antifouling property of the membrane. Intercalation of TiO2 nanoparticles efficiently improved the porosity and wettability of the polymeric membranes, which could be confirmed by the contact angle analyzer analysis. The modified PVDF membranes exhibited excellent antimicrobial properties against Gram-negative Escherichia coli as confirmed from the halo zone and activity test. The permeation experimental results also showed high protein rejection of bovine serum albumin and humic acid (foulant) for membranes with optimum TiO2 loading of 0.01 g/g of PVDF polymer. However, at a concentration of 0.02 g TiO2/g of PVDF a negative effect on the membrane property was observed due to the former non-uniform distribution.

Effect of TiO2 on the crystallization and properties of MgO-Al2O3-SiO2 glass-ceramics prepared by an "one-step" method from laterite ore

In the current paper, we proposed a novel, "one-step" method to simultaneously prepare MgO-Al2O3-SiO2 glass-ceramics and Ni-Fe alloy from laterite ore with the addition of TiO2. The "one-step" method makes full use of the thermal energy of the molten slag so that the energy consumption for the production of the glass-ceramics is much lower than that in a more conventional method. Moreover, the slag utilization rate can reach 100%. In this method, 0–4 g of TiO2 as a nucleating agent was added into laterite ore to control the phase composition and microstructure of glass-ceramics. The effects of the addition of different amounts of TiO2 on the crystallization behaviour, major crystalline phase, microstructure and various properties of glass-ceramics were investigated by XRD, SEM, EDS and a Vickers hardness tester. The results show that with an increase in the amount of TiO2 added (0–3 g), the μ-cordierite gradually precipitated and became the main crystalline phase of the glass-ceramics. Meanwhile, the crystallinity, grain size and acid/alkali resistance were all enhanced with increased TiO2 addition. The micro-hardness increased from 6.699 GPa to 9.156 GPa. However, as the amount of TiO2 added increased up to 4 g, a large amount of sapphirine ((Mg4Al4)(Al4Si2)O20) precipitated in the glass-ceramics. The major crystalline phase of the glass-ceramics begins to change from μ-cordierite to sapphirine, accompanied by a decrease of its density, acid/alkali resistance and micro-hardness. This study is helpful for extending the "one-step" method of simultaneously preparing glass-ceramics and metals to other low-grade ores and not just laterite ore.

Investigation of the effect of titanium dioxide and clay grafted with glycidyl methacrylate by gamma radiation on the properties of EVA flexible films

Many studies report that nanocomposites obtained by dispersion of a small amount nanofiller into the polymer have remarkable improvements achieved in the mechanical and physical properties. However, in order to achieve this great improvement in properties, it is necessary that the nanofillers be dispersed homogeneously into the polymeric matrix. Often this dispersion is difficult to achieve due to the high interfacial energy of the nanoparticles present. This study reports the effect of gamma irradiation induced graft of glycidyl methacrylate (GMA) onto the surface of TiO2 and Clay nanofillers to improve their dispersion into the EVA matrix. The physical and mechanical properties of Ethylene-vinyl acetate copolymer (EVA) flexible films with these nanoparticles were studied. EVA nanocomposite with adding of the different amount of TiO2 and modified montmorillonite clay grafted and un-grafted with glycidyl methacrylate (GMA) using gamma irradiation have been prepared by melt extrusion. The nanocomposite flexible films were produced using a flat die extrusion process. The PGMA-grafted nanofillers were characterized by XRD and TEM analysis. The flexible films were characterized by Tensile tests, ATR–FTIR, UV–VIS, XRD, TG, and FE-SEM analysis to understand the nature of the interaction between the nanofillers and EVA matrix. The results showed that the addition of PGMA-grafted TiO2 and Clay nanofillers into EVA matrix improved the bonding between the nanofillers and matrix. It was also found that the PGMA-grafted nanofillers could be well dispersed into an EVA matrix in contrast to that of un-grafted. The tensile strength and modulus of the resulting EVA/TiO2-PGMA enhanced in comparison to that of un-grafted TiO2. The EVA/Clay-PGMA had slightly decreased tensile strength comparable to that of EVA/Clay but had considerably improved elastic modulus. In addition, the flexible films based on TiO2 exhibited high UV–Vis light absorption with energy gap shifted to the visible region. The results demonstrated that TiO2 and Clay nanofillers grafted with GMA by gamma radiation can be used to prepare EVA flexible films with improved bonding between the nanofillers and matrix and, consequently, enhanced properties for food and cosmetic packaging application.

Green synthesis of titanium dioxide/acrylamide-based hydrogel composite, self degradation and environmental applications

A green polymerization using TiO2 as an inorganic photoinitiator to synthesize titanium dioxide/poly[acrylamide-co-(acrylic acid)] hydrogel composite was successfully achieved. FTIR and SEM/EDXS characterizations indicated that the hydrogel composites were the crosslinked copolymer composed of acrylamide and acrylic acid in TiO2 particles. TiO2 hydrogel composites could adsorb up to 90% of 5 ppm methylene blue dye solution. Decolorization of methylene blue by the hydrogel composites was evaluated by colorimetry in term of K/S value. Approximately 83% of methylene blue was decolorized in 8 h by 5% TiO2 hydrogel composite and 90% decolorization in 8 h for 10% TiO2 hydrogel composites. The maximum color fading of methylene blue in the hydrogel composites at various UV irradiation times was observed by the slope of the linear region at different amounts of TiO2. It reveals that AMAA5050T10C1 gave the highest methylene blue fading of 91.6% with an R2 of 0.9999. The slope of 5 ppm Congo red in AM-T20-C1 adsorbent obeying a Pseudo-first order gave the highest dye removal of 44.8% with an R2 of 0.9572. This technique meets the criteria of green chemistry because the reaction does not need any organic photoinitiator or co-photoinitiator and the reaction takes place at room temperature. Congo red in polyacrylamide hydrogel composite containing 20% TiO2 obeyed a Pseudo-first order kinetics giving qe,exp = 2.22 mg g−1 (qe,cal = 2.24 mg g−1) while methylene blue in poly[acrylamide-co-(acrylic acid)] hydrogel composite at 50:50 monomer weight ratio containing 5% TiO2 followed a Pseudo-second order kinetics having qe,exp = 4.86 mg g−1 (qe,cal = 4.73 mg g−1). The rheological measurement of the TiO2/poly[arylamide-co-(acrylic acid)] hydrogel composites revealed a strong gel-like material and the self-degradation of the hydrogel composites evolved under UVA irradiation. TiO2/poly[(acrylamide)-co-(acrylic acid)] hydrogel composites synthesized in current work can be used as a model for both green synthesis of the hydrogel composites using an ionic photocatalyst, TiO2, and for degradation of organic dyes and self-degradation of the composites upon UV irradiation.

Graphene oxide and TiO2 based PMMA nanocomposites for dental applications: A comprehensive study of the mechanical properties

This work reports synthesis of PMMA/TiO2 blend nanocomposite for its application as dental materials. Two different amount of TiO2nano particles 1% (wt.) was mixed homogeneously through melt compounding with constant ratio of PMMA to obtain desired properties. The properties of these two bend nanocomposites were compared GO (0.001% wt.) reinforcedPMMAnanocomposite for the same purpose. Asprepared blend nanocomposites were characterized by Field Emission Scanning Electron Microscopy (FESEM), depth indentation, and sratch analysis. Moreover, this work also showing effect of different amount of TiO2 on open ring hole structures and matrix droplet morphology. So, that this work may open up an opportunities to produce new compatibilized blend that are of great interest in the industrial applications using specific amount of TiO2.

A rapid tool for determination of titanium dioxide content in white chickpea samples

Titanium dioxide (TiO2) is a widely used additive in foods. However, in the scientific community there is an ongoing debate on health concerns about TiO2. The main goal of this study is to determine TiO2 content by using laser induced breakdown spectroscopy (LIBS). To this end, different amounts of TiO2 was added to white chickpeas and analyzed by using LIBS. Calibration curve was obtained by following Ti emissions at 390.11nm for univariate calibration, and partial least square (PLS) calibration curve was obtained by evaluating the whole spectra. The results showed that Ti calibration curve at 390.11nm provides successful determination of Ti level with 0.985 of R2 and 33.9ppm of limit of detection (LOD) value, while PLS has 0.989 of R2 and 60.9ppm of LOD. Furthermore, commercial white chickpea samples were used to validate the method, and validation R2 for simple calibration and PLS were calculated as 0.989 and 0.951, respectively.

Photochemical insights of TiO2 decorated mesoporous SBA-15 materials and their influence on the photodegradation of organic contaminants

Mesoporous silica, SBA-15, decorated with different amounts of TiO2 (anatase) were prepared by a sol-gel method followed by hydrothermal treatment and calcination, in the presence of a soft template, copolymer Pluronic 123. Tetraethyl orthosilicate (TEOS) was used as the SiO2 precursor and commercially available TiO2 anatase nanoparticles as the supported photocatalyst. The materials were characterized by transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDS), N2 adsorption-desorption isotherms, raman spectroscopy, ground state diffuse reflectance (GSDR), laser induced luminescence (LIL) and X-ray photoelectron spectroscopy (XPS). The zeta potentials of the pure SBA-15, TiO2/SBA-15 substrate and the commercial anatase sample were monitored through a complete range of pH values. All the nanomaterials developed in this work were studied in terms of their photoactivity in the UV range and in the visible range, separately. In the first case, hydroxyl radicals (OH) were confirmed to be the key active oxidizers in the photodegradation of the pesticide amicarbazone in aqueous medium. On the other hand, in the visible range, and following a dye sensitization process via a fluorescent rhodamine-like dye, two different mechanisms could be identified for the formation of the superoxide radical anion, O2−.

Electrosynthesis, characterization and photoconducting performance of copolymer poly(terthiophene + sexithiophene + TiO2)/ITO composite material

In the present work, a new composite material poly(3T + 6T + TiO2) was electrochemically synthesized. This composite material was synthesized in a solution of (CH2Cl2/TBAP) containing the monomers (terthiophene), (sexithiophene) and semiconductor (TiO2) particles. The preparedsamples were characterized electrochemically by cyclic voltamperometry (CV) and spectrometry analysis by scanning electron microscopy (SEM), ultraviolet-visible (UV-Vis) absorption spectroscopy, energy dispersive X-ray spectroscopy (EDX) and fourier transform infrared spectroscopy (FTIR), respectively. The effect of TiO2 concentration in the solution on dispersed microparticle entity and on the photocurrent response was investigated. The results showed that TiO2 particles were dispersed and codeposited into the copolymer poly(3T + 6T + TiO2) matrix, and titanium atom was confirmed by EDX spectra. From SEM images, the TiO2 has a spherical shape and micrometer size. The FTIR spectrum indicated that titanium dioxide do not show a significant modification in terms of band shape and no interaction between polymers and TiO2 particles. Furthermore, the results showed that the composite films with different amounts of TiO2 exhibit good photocurrent properties which imply that these composites films can be used in various fields, such as photoelectrochemical applications as photovoltaic cells.

Photocatalytic activity of wool fabrics deposited at low temperature with ZnO or TiO2 nanoparticles: Methylene blue degradation as a test reaction

Different amounts of TiO2 and ZnO particles were deposited upon wool fabrics, which are among the less studied textiles. The materials were get from industry or were home made. Model samples for these oxide deposition and properties were also considered. Either sputtering or chemical sol-gel/electro less technique was respectively applied. The coated samples were then characterized structurally and morphologically, by XRD, SEM and XPS and were checked for photocatalytic properties. Both UV and vis light beams were used for irradiation. The photocatalytic experiments were performed by photodegradation of methylene blue in the PCC2 checker apparatus. The fabrics were firstly impregnated with the dye solution and then dried: self cleaning of the wool fabric samples took in fact place. Reflectance data in the visible spectral range of highest absorption band served for direct analysis of MB degradation. The photocatalytic properties of the coated fabrics increased much in comparison with the raw materials. The photocatalytic decolorization of methylene blue follows up a simple apparently first order kinetic equation in many studied cases. Thus it was demonstrated that MB decolorization can serve as a test reaction at least for self cleaning of fabrics.

Hierarchically Templated Synthesis of Hollow Nanoporous Gold Rods and TiO2‐Coated Gold Rods

AbstractGold nanomaterials have shown promising applications in catalysis and sensing. Among the current directions in the research and development of gold catalysts, the exploration of new forms is one of the major priorities. Using bacteria as the supporting template and polystyrene spheres as the pore‐generation template, a hierarchical‐template synthesis strategy was developed in the present study to synthesize hollow nanoporous gold rods. The pore size can be easily adjusted by using polystyrene spheres (PSS) with different diameters as the template (the pore size is about 160 nm and 70 nm when using 200 nm and 110 nm PSS, respectively, as the template). Moreover, with the simple sol–gel method, different amounts of TiO2 can be coated on these nanoporous gold rods. The results showed the thermal stability and catalytic activity of the nanoporous gold rods were improved dramatically with moderate TiO2 coating. Using reduction of 4‐nitrophenol to 4‐aminophenol with sodium borohydride as the model reaction, excellent catalytic properties (reaction rate constant k=0.246 min−1) of the prepared TiO2‐coated gold rods catalysts were confirmed.

Fabrication and study of UV-shielding and photocatalytic performance of uniform TiO2/SiO2 core-shell nanofibers via single-nozzle co-electrospinning and interface sol–gel reaction

One-dimensional TiO2/SiO2 core-shell nanofibers were fabricated using a single-nozzle co-electrospinning process with phase-separated, mixed polymer composite solution. The core and shell are composed of Polyvinylpyrrolidone (PVP) and Polyacrylonitrile (PAN) polymers with uniform distribution of TiO2 and SiO2 nanoparticles (NPs), respectively. The NPs were synthesized via sol-gel reaction, simultaneously, in the respective polymer solutions. The morphologies and structures of the fabricated TiO2/SiO2 core-shell nanofibers were investigated by XRD, FTIR, SEM, EDS and TEM images. The influence of different amounts of TiO2 and SiO2 precursors on the photocatalytic and UV-shielding performance of TiO2/SiO2 core-shell nanofibers were studied. Photocatalytic activity of the nanofibers evaluated by observing photodegradation of Methyl Orange (MO) aqueous solution under irradiation of ultraviolet (UV) light. Our results on the TiO2/SiO2 core-shell nanofibers indicate good potential for superior applications in photocatalytic and UV shielding devices.

Sol-Gel TiO2 and ZrO2-Nanocomposite Thin Films for Enhancing in Vitro Biocompatibility and Bio-Corrosion Resistance of Ti6Al4V Orthopaedic Implants

The aim of this work has been to study the effect of TiO2 and ZrO2-silane sol-gel coatings on the corrosion resistance and biocompatibility of Ti6Al4V biomedical alloys. The sol used for coating was an aqueous solution containing 3-methacryloxypropyltrimethoxysilane (MAPTMS), tetramethoxysilane (TMOS) and titanium tetrabutoxide (TBT) or zirconium tetrabutoxide (ZBT). A system without tetrabutoxides was used as reference. The effect of the addition of different amounts of TiO2 or ZrO2 precursors on the thermal stability of the prepared organic-inorganic hybrids was investigated by using thermal analysis (TG/DTG). Structural characterization of the coatings was carried out using Attenuated Total Reflectance Fourier Transformer Infrared Spectroscopy (ATR-FTIR). Contact angle measurements were used to study the hydrophilicity of the coatings. The thickness of the resulting sol-gel coatings was measured by using a profilometer. Scanning Electron Microscopy coupled with Energy Dispersive X-ray (SEM/EDX) were applied to study the surface morphology and composition of the MAPTMS/TMOS/TiO2 and MAPTMS/TMOS/ZrO2 coatings. Global and Local electrochemical Impedance Spectroscopies (EIS and LEIS) and potentiodynamic polarization measurements during immersion in Dulbecco’s Phosphate Buffered Saline with MgCl2 and CaCl2 (PBS) were carried out to evaluate the barrier properties on the coatings. In vitro bioactivity was assessed by soaking the nanocomposite coatings at 36.5ºC up to 14 days in the Kokubo’s simulated body fluid (SBF; pH 7.4). After applying the soaking tests the samples were removed from the SBF, rinsed with ddH2O and dried at room temperature and submitted to analysis by XRD, SEM and EDX. In parallel studies the biocompatibility of these sol-gel coatings has been evaluated. In this way protein adsorption was studied using fibrinogen as a representative protein. Adsorbed protein was determined by applying the Bradford method and ATR-FTIR after immersion the sol-gel thin films in fibrinogen. In summary SEM observations of these coatings showed the formation of a uniform, homogeneous, crack free and highly adherent protective film on the substrates. The electrochemical techniques indicated that the incorporation of TiO2 and ZrO2 nanoparticles in the MAPTMS-TMOS matrix improved the corrosion protection properties of the organic-inorganic hybrid coatings. SEM/EDX analyses showed bone-like precipitates after 14 days of immersion in SBF. XRD detected trace amounts of Ca and P in these precipitates but it was not possible to determine conclusively their nature. The in vitro biocompatibility studies confirmed that these sol-gel thin films can be good candidates to develop coatings for Ti6Al4V orthopaedic implants. Acknowledges: This work was supported by the Ministry of Economy and Competitiveness of Spain (Projects MAT2012-38541-C02-02, MAT2012-30854 and MAT2015-65445-C2-1-R).

Synthesis and characterization of insulin/zirconium phosphate@TiO2 hybrid composites for enhanced oral insulin delivery applications

In this work, a series of composites of insulin (Ins)/zirconium phosphate (ZrP) were synthesized by intercalation method, then, these composites were coated with TiO2 by sol-gel method to prepare Ins/ZrP@TiO2 hybrid composites and the drug release of the composites was investigated by using UV-Vis spectroscopy. Ins/ZrP (10, 30, 60 wt%) composites were prepared by intercalation of insulin into the ZrP layers in water. Then Ins/ZrP composites were coated with different amounts of TiO2 (30, 50, 100 wt %) by using titanium tetra n-butoxide, as precursor. Formation of intercalated Ins/ZrP and Ins/ZrP@TiO2 hybrid composites was characterized by FT-IR, FE-SEM, BET and XRD analysis. Zeta potential of the optimized Ins/ZrP@TiO2 hybrid composite was determined −27.2 mV. Cytotoxic effects of the optimized Ins/ZrP@TiO2 hybrid composite against HeLa and Hek293T cell lines were evaluated using MTT assay and the results showed that designed drug delivery system was not toxic in biological environment. Compared to the Ins/ZrP composites, incorporation of TiO2 coating enhanced the drug entrapment considerably, and reduced the drug release. The Ins/ZrP composites without TiO2 coating released the whole drug after 30 min in pH 7.4 (phosphate buffer solution) while the TiO2-coated composites released the entrapped drug after 20 h. In addition to increasing the shelf life of hormone, this nanoencapsulation and nanocoating method can convert the insulin utilization from injection to oral and present a painless and more comfortable treatment for diabetics.

Preparation and characterization of ibuprofen/modified chitosan/TiO2 hybrid composite as a controlled drug-delivery system

In this study, a modified chitosan was chemically synthesized from chitosan in two steps, (1) addition of methyl acrylate followed by (2) diethylenetriamine. The modified chitosan (MC) characterized by FT-IR spectroscopy and was used as carrier for loading of ibuprofen (IBU), an anti-inflammatory drug. Hence, a series of IBU/MC composites were prepared and the drug release of the composites was investigated by using UV–Vis absorbance technique. In order to improve the release behaviour of composites, they were coated with different amounts of TiO2 (30–60 wt%) using titanium tetra n-butoxide, as precursor. The prepared IBU/MC/TiO2 hybrid composites were characterized by FT-IR, TG, XRD, FE-SEM, DSC, BET, DLS and Zeta potential analysis. Coating with TiO2 enhanced the drug entrapment considerably, and reduced the drug release, so that uncoated and coated composites had drug release over 24 h and 54, respectively. Moreover, hybrid composites of IBU/MC/TiO2 revealed that drug release is pH sensitive. The release rate of IBU in the simulated gastric fluid (pH 1.2) was noticeably slower than pH 7.4. The results indicate that the prepared hybrid composites could decrease side effects of the drug by minimizing the contact between the drug and the gastric fluid.