Nanoparticle-loaded TiO2 Research Articles

S-scheme TiO2/Bi2WO6 heterojunction for enhanced photocatalytic selective oxidation of toluene

Selective activation of saturated C–H bonds in hydrocarbons, such as the activation of the C–H bond in toluene, is an effective method for the production of high value-added chemicals. However, improving the C–H bond activation of toluene remains a challenge. In this study, S-scheme TiO2/Bi2WO6 composites were synthesized by loading TiO2 nanoparticles on Bi2WO6 flakes using a simple hydrothermal method. The physical and chemical properties of the prepared materials were characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectoscopy (FT-IR), Scanning Electronic Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS) and other characterization methods. Selective oxidation of toluene to benzaldehyde under visible light irradiation using air as an oxidizing agent. When the molar ratio of TiO2 and Bi2WO6 was 0.20, the composites exhibited excellent photocatalytic performance with a benzaldehyde production rate of 1725.41 μmol g−1 h−1, which was 2.31 and 1.91 times higher than that of TiO2 and Bi2WO6, respectively. This excellent performance is attributed to the formation of heterojunction structure by the loaded TiO2 nanoparticles, which improves the separation efficiency of photogenerated carriers and thus enhances its photocatalytic performance. In addition, the active substances involved in the photocatalytic reaction were identified by free radical trapping experiments as ·O2− and h+. Finally, the photocatalytic mechanism of S-scheme TiO2/Bi2WO6 composites was proposed by energy band structure analysis and radical trapping experiments. This study provides a simple design pathway for the construction of visible-light responsive bismuth tungstate-based heterojunction photocatalysts and some ideas for the development of new and efficient photocatalytic toluene selective oxidation catalysts.

A Layered Titanate Nanowire Helps Pt/TiO2 Photocatalyst for Solar Hydrogen Evolution from Water with High Quantum Efficiency

Abstract Research into TiO2 photocatalysts for solar H2 evolution from water is still growing for environmentally benign and economically valid H2 production. Herein, in contrast to many researches on the modification of TiO2 toward higher photocatalytic activities, we develop a photocatalytically inactive TiO2-based nanostructure and use it, like graphene, as a booster of a benchmark TiO2. A layered potassium titanate with two-dimensional plate-like particle morphology was converted to the corresponding one-dimensional nanowire form via a hydrothermal reaction, after which the layered potassium titanate nanowire was acid-treated to obtain a layered titanate nanowire. This nanowire was completely inactive toward H2 evolution from water containing methanol under solar simulator irradiation. However, when Pt nanoparticle-loaded P25 TiO2 (Pt/P25) was mixed with a considerably smaller amount of the layered titanate nanowire in water, a durable composite was obtained and the composite showed a good photocatalytic activity three times higher than Pt/P25. The apparent quantum efficiency of the reaction at wavelength of 350 nm was 56%, which was higher than or comparable to those of the state-of-the-art TiO2-based photocatalysts. The possible reason for the enhanced photocatalytic activity of the Pt/P25 and layered titanate nanowire composite involved the transfer of photogenerated holes from Pt/P25 to the nanowire to suppress charge recombination and/or disaggregation (improved dispersion) of Pt/P25 particles on the nanowire.

Fabrication of porous polymeric-based scaffold for dental tissue repair in fracture healing: RVE simulation and ANN optimization

In this study, a porous scaffold composed of polyvinylpyrrolidone (PVP) and alginate containing titanium nanoparticles (Ti-NPs or TiO2 nanoparticles) layer by layer was produced using biodegradable polymers and a freeze-drying technique. The prepared porous scaffold was evaluated for its mechanical and biological behavior, such as swelling, porosity, and biodegradability in phosphate buffer saline (PBS) and simulated body fluid (SBF), through scanning electron microscopy (SEM) analysis. The incorporation of hydrophilic polymers increased the amount of water absorption, reaching 811 ± 214% in the layer-by-layer scaffold, which was significantly different from pure PVP. Cell culture of rat bone marrow stem cells (rMSC) on the scaffold showed a cell survival percentage above 80% after 3, 5, and 7 days, and the morphology of the cells indicated optimal biocompatibility. Furthermore, multi-scale finite element modeling (FEM) was used to predict the mechanical properties of the fabricated scaffold with different porosity percentages. Four types of representative volume elements (RVEs) were generated with randomly distributed 74%, 79%, 81%, and 84% porosity. The tensile strength and stress–strain curves of the specimens were obtained using an ABAQUS/Explicit solver attached with VUSDFLD subroutines to evaluate the elastic modulus of simulation results. The numerical results demonstrated good agreement with experimental results, indicating the reliability of the developed FEM for predicting the tensile properties of the fabricated porous scaffold. Finally, an artificial neural network (ANN) was developed to determine the effect of weight percentages (wt. %) of loaded TiO2 nanoparticles into bone scaffolds on the porosity and elastic modulus. The predicted results from the ANN showed an increase in the porosity and elastic modulus with an increase in wt. % of TiO2. The generated ANN can be used to determine the optimal amount of nanoparticles for various applications of dental scaffolds.

Mesoporous TiO2 Coatings Regulate ZnO Nanoparticle Loading and Zn2+ Release on Titanium Dental Implants for Sustained Osteogenic and Antibacterial Activity.

Two major issues are currently hindering the clinical practice of titanium dental implants for the lack of biological activities: immediate/early loading risks and peri-implantitis. To solve these issues, it is urgent to develop multifunctional implants modified with effective osteogenic and antibacterial properties. Zinc oxide nanoparticles (ZnO NPs) possess superior antibacterial activity; however, they can rapidly release Zn2+, causing cytotoxicity. In this study, a potential dental implant modification was creatively developed as ZnO nanoparticle-loaded mesoporous TiO2 coatings (nZnO/MTC-Ti) via the evaporation-induced self-assembly method (EISA) and one-step spin coating. The mesoporous TiO2 coatings (MTCs) regulated the synthesis and loading of ZnO NPs inside the nanosized pores. The synergistic effects of MTC and ZnO NPs on nZnO/MTC-Ti not only controlled the long-term steady-state release of Zn2+ but also optimized the charge distribution on the surface. Therefore, the cytotoxicity of ZnO NPs was resolved without triggering excessive reactive oxygen species (ROS). The increased extracellular Zn2+ further promoted a favorable intracellular zinc ion microenvironment through the modulation of zinc transporters (ZIP1 and ZnT1). Owing to that, the adhesion, proliferation, and osteogenic activity of bone mesenchymal stem cells (BMSCs) were improved. Additionally, nZnO/MTC-Ti inhibited the proliferation of oral pathogens (Pg and Aa) by inducing bacterial ROS production. For in vivo experiments, different implants were implanted into the alveolar fossa of Sprague-Dawley rats immediately after tooth extraction. The nZnO/MTC-Ti implants were found to possess a higher capability for enhancing bone regeneration, antibiosis, and osseointegration in vivo. These findings suggested the outstanding performance of nZnO/MTC-Ti implants in accelerating osseointegration and inhibiting bacterial infection, indicating a huge potential for solving immediate/early loading risks and peri-implantitis of dental implants.

A facile and new preparation of crystalline Ag loaded TiO2 nanoparticles by a one-step method at room temperature

Crystalline Ag loaded TiO2 (c-Ag/TiO2) nanoparticles (NPs) has higher photocatalytic activity than amorphous Ag loaded TiO2 (a-Ag/TiO2) NPs, but its preparation usually requires multi steps and high temperatures. In this work, c-Ag/TiO2 NPs have been successfully prepared by one-step UV reduction at room temperature, using TiO2 (P25) and AgNO3 as raw materials. The phase, grain size, crystallinity and morphology of such c-Ag/TiO2 NPs have been analyzed by X-ray diffraction, element surface distribution and field emission transmission electron microscope. The crystal plane form of TiO2 is the main factor affecting the formation of c-Ag/TiO2 in the process of photoreduction of Ag+ to Ag0 on the surface of TiO2 at room temperature. Among the anatase and rutile phases of TiO2 (P25), rutile TiO2 (101) crystal plane is the predominant crystal plane for precipitation of crystalline Ag (111) to form c-Ag/TiO2.

Enhanced gas sensing and photocatalytic activity of reduced graphene oxide loaded TiO2 nanoparticles

In the present study, we have evaluated the gas sensing and photocatalytic activity of reduced graphene oxide (rGO) conjugated titanium dioxide (TiO2) nanoparticles (NPs) formed by the hydrothermal method. The as-synthesized rGO-TiO2 nanocomposite were characterized for the physicochemical properties such as the nature of crystallinity, functionalization, and morphology by making use of the powder X-ray diffraction, Fourier transform-infrared spectroscopy, and scanning electron microscopy, respectively. On testing the gas sensing properties, we found that the rGO-TiO2 nanocomposite can serve as the chemoresistive-type sensor because of its sensitivity and selectivity towards different concentrations of hydrogen and oxygen at room temperature conditions. However, the rGO-TiO2 sensor’s response and recovery speed towards hydrogen and oxygen needs further optimization. Test of photocatalytic activity of TiO2-rGO catalyst for the removal of two model contaminant dyes, RhB and MB showed effective removal, with respective degradation percentages of about 80 and 90% within the first 50 min of irradiation under visible light irradiation. Besides, MB was more effectively degraded using TiO2-rGO than pure TiO2 during the first 30 min of irradiation and this enhanced activity can be attributed to the increased capacity of light absorption, the efficiency of charge carriers separation, and the specific surface area maintained by the rGO-TiO2 nanocomposite to effectively utilize the photo-generated holes (h+) and superoxide radicals (O2−), responsible for the degradation of the dye. Based on the overall analysis, the formation of rGO-TiO2 nanocomposite can significantly improve the gas sensing and photocatalytic properties of TiO2 NPs and thus can be potential for practical applications in future nanotechnology.

Binding interaction of 5-amino-2-mercaptobenzimidazole with Au-TiO2: inhibition of switch-on fluorescence

Gold loaded TiO2 nanoparticles was synthesized and characterized by powder XRD, HR-TEM, and EDX analysis. The binding interaction of 5-amino-2-mercaptobenzimidazole (fluorochrome) with TiO2 and gold loaded TiO2 nanoparticles was discussed herein. The interaction of fluorochrome with TiO2 and Au-TiO2 nanoparticles has been studied by UV-visible, fluorescence, and FT-IR spectral techniques. Fluorescence emission occurs at 421 nm and this has been selectively enhanced by TiO2 nano semiconductor. This technique is sensitive to detect and estimate TiO2 nano semiconductor at a micromolar level. This switch-on fluorescence is obtained when fluorochrome is binds with TiO2 nanoparticles. This increase in fluorescence is suppressed when TiO2 nanoparticles is loaded with gold. This is because of chemo sensing nature of the gold. The strong adsorption of fluorochrome over the surface of nano semiconductor results in the electron transfer between fluorochrome and semiconductor. Further, the binding site of semiconductor with fluorochrome has been studied theoretically by molecular electrostatic potential diagram.

Vorinostat-loaded titanium oxide nanoparticles (anatase) induce G2/M cell cycle arrest in breast cancer cells via PALB2 upregulation

Breast cancer is a group of diseases in which cells divide out of controlled, typically resulting in a mass. Erlotinib is targeted cancer drug which functions as an inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase. It is used mainly to treat of non-small cell lung cancer patients and has an action against pancreatic cancer. Vorinostat (aka suberanilohydroxamic acid) is an inhibitor of histone deacetylases (HDAC), which has an epigenetic modulation activity. It is used to treat cutaneous T cell lymphoma. In the present study, the erlotinib (ERL) and vorinostat (SAHA) loaded TiO2 nanoparticles (NPs) were used for the treatment of the breast cancer cells (MDA-MB-231 and MCF-7) and human cancerous amniotic cells (WISH). Cell count and viability were negatively affected in all treatments compared to normal cells and bare TiO2 NPs. Apoptosis results indicated a significant increase in the total apoptosis in all treatments compared with control cells. ERL- and SAHA-loaded TiO2 NPs treatments arrested breast cancer cells at G2/M phase, which indicate the cytotoxic effect of these treatment. Partner and localizer of BRCA2 (PALB2) gene expression was assessed using qPCR. The results indicate that PLAB2 was upregulated in ERL- and SAHA-loaded TiO2 NPs compared with control cells and can be used as nanocarrier for chemotherapy drugs. However, this conclusion necessitates further confirmative investigation.

Improved Immunoregulation of Ultra-Low-Dose Silver Nanoparticle-Loaded TiO2 Nanotubes via M2 Macrophage Polarization by Regulating GLUT1 and Autophagy.

IntroductionThe bone regeneration of endosseous implanted biomaterials is often impaired by the host immune response, especially macrophage-related inflammation which plays an important role in the bone healing process. Thus, it is a promising strategy to design an osteo-immunomodulatory biomaterial to take advantage of the macrophage-related immune response and improve the osseointegration performance of the implant.MethodsIn this study, we developed an antibacterial silver nanoparticle-loaded TiO2 nanotubes (Ag@TiO2-NTs) using an electrochemical anodization method to make the surface modification and investigated the influences of Ag@TiO2-NTs on the macrophage polarization, osteo-immune microenvironment as well as its potential molecular mechanisms in vitro and in vivo.ResultsThe results showed that Ag@TiO2-NTs with controlled releasing of ultra-low-dose Ag+ ions had the excellent ability to induce the macrophage polarization towards the M2 phenotype and create a suitable osteo-immune microenvironment in vitro, via inhibiting PI3K/Akt, suppressing the downstream effector GLUT1, and activating autophagy. Moreover, Ag@TiO2-NTs surface could improve bone formation, suppress inflammation, and promote osteo-immune microenvironment compared to the TiO2-NTs and polished Ti surfaces in vivo. These findings suggested that Ag@TiO2-NTs with controlled releasing of ultra-low-dose Ag+ ions could not only inhibit the inflammation process but also promote the bone healing by inducing healing-associated M2 polarization.DiscussionUsing this surface modification strategy to modulate the macrophage-related immune response, rather than prevent the host response, maybe a promising strategy for implant surgeries in the future.

Hydrogen peroxide synthesis from water and oxygen using a three-component nanohybrid photocatalyst consisting of Au particle-loaded rutile TiO2 and RuO2 with a heteroepitaxial junction.

Thin heteroepitaxial (HEPI) layers of RuO2 were selectively formed on the TiO2 surface of Au nanoparticle-loaded rutile TiO2 particles (RuO2#TiO2-Au) with an orientation of RuO2(110)//TiO2(110) by a hydrothermal method, and the three-component nanohybrid exhibits a high photocatalytic activity far exceeding that of Au/TiO2 for hydrogen peroxide generation from water and oxygen due to the HEPI junction-induced unique morphology of RuO2.

The preparation and performance of Au loads TiO2 nanomaterials

In this experiment, gold loaded TiO2 nanoparticles (AuNPS@TiO2NPS) and nanowires (AuNPS@TiO2NWS) were successfully prepared through one step hydrothermal reaction. The photocatalytic experimental results showed that the catalytic efficiency of Au loaded TiO2 increases with the increase of Au ratio. When the gold content was 5%, both AuNPS@TiO2NPS and AuNPS@TiO2NWS performed well in catalysis Methylene blue. It was also clear that AuNPS@TiO2NWS performed better than that of AuNPS@TiO2NPS. After calcination at 800 °C for 3 h under the protection of Ar, the crystal phase of both samples shifted to rutile. Furthermore, from SEM and TEM image, the linear structure was destroyed under high temperature which decreased the catalytic efficiency. It indicated that the crystal phase was strengthened and the catalytic effect was improved obviously by calcinations. By comparing the catalytic efficiencies of dyes with different initial concentrations after 5 h under UV irradiation, the time and content at which the AuNPS@TiO2NPS and AuNPS@TiO2NWS reached degradation saturation were related to the potential of catalyst surface. After five times of repeated use, the degradation rate could still be 87.25% for Methylene blue, 81.65% for Rhodamine B and 79.70% for Azophloxine. The results would indicate that the samples as prepared had good recycling performance.

Long-lasting bactericidal activity through selective physical puncture and controlled ions release of polydopamine and silver nanoparticles-loaded TiO2 nanorods in vitro and in vivo.

Background: Titanium (Ti) implant-associated infection, which is mostly caused by bacterial adhesion and biofilm formation, may result in implant failure and secondary surgery. Thus it is an urgent issue to prevent bacterial infections at the earliest step.Purpose: To develop a novel surface strategy of polydopamine (PDA) and silver (Ag) nanoparticle-loaded TiO2 nanorods (NRDs) coatings on Ti alloy.Materials and methods: Ag-TiO2@PDA NRDs was fabricated on Ti alloy by hydrothermal synthesis. The antibacterial activity of Ag-TiO2@PDA NRDs against Escherichia coli and methicillin-resistant Staphylococcus aureus were tested by FE-SEM, Live/Dead staining, zone of inhibition, bacteria counting method and protein leakage analysis in vitro. In addition, an implant infection model was conducted and the samples were tested by X-ray, Micro-CT and histological analysis in vivo. Besides, cell morphology and cytotoxicity of Mouse calvarial cells (MC3T3-E1) were characterized by FE-SEM, immunofluorescence and CCK-8 test in vitro.Results: Our study successfully developed a new surface coating of Ag-TiO2@PDA NRDs. The selective physical puncture of bacteria and controlled release of Ag+ ions of Ag-TiO2@PDA NRDs achieved a long-lasting bactericidal ability and anti-biofilm activity with satisfied biocompatibility.Conclusion: This strategy may be promising for clinical applications to reduce the occurrence of infection in the implant surgeries

Poly(dopamine) and Ag nanoparticle-loaded TiO2 nanotubes with optimized antibacterial and ROS-scavenging bioactivities.

To create polydopamine (PDA) and Ag nanoparticle-loaded TiO2 nanotubes coating on titanium (Ti) alloy. TiO2-PDA-Ag coating was fabricated on Ti implants by electrochemical anodization. The in vitro and in vivo bactericidal and antibiofilm activities were tested. Intracellular reactive oxygen species (ROS) and antioxidative capability were measured, and cell proliferation, adhesion and cell morphology were characterized. TiO2-PDA-Ag coating showed satisfactory bactericidal and antibiofilm activities in vitro and in vivo, improved Ag release pattern, evident ROS scavenging properties and enhanced cell adhesion and proliferation. Our study successfully fabricated a PDA and Ag nanoparticle-loaded TiO2 nanotubes coating on Ti alloy. The improved Ag release kinetics and ROS-scavenging properties achieve an optimal balance between antibacterial ability and biocompatibility.

Water-Dispersible Rhodamine B Hydrazide Loaded TiO₂ Nanoparticles for "Turn On" Fluorimetric Detection and Imaging of Orthosilicic Acid Accumulation In-Vitro in Nephrotoxic Kidney Cells.

Silica (SiO2) is the inevitable form of silicon owing to its high affinity for oxygen, existing as a geogenic element perpetrating multifarious health problems when bioavailable via anthropogenic activities. The hydrated form of silica viz. orthosilicic acid (H4SiO4) excessively displays grave toxicity, attributed to prolonged exposure and incessant H+ ions generating capacity inflicting pulmonary toxicity and renal toxicity silica. The diverse deleterious potency of silica highlights the desirability of selective and sensitive detection of toxic species (mainly orthosilicic acid) bioaccumulation in affected living human cells. In this paper we have reported, the design of water-dispersible turn-on fluorimetric sensing material for the detection of orthosilicic acid in the aqueous phase and in live cells. The sensing material was prepared by adsorbing a suitable rhodamine derivative (i.e., Rhodamine B hydrazide (Rh1)) on water dispersible TiO2 nanoparticles. The function of the sensing system, which is composed of Rh1 and TiO2 (Rh1@TiO2), is accredited to H+ ion (from orthosilicic acid) induced spirolactam ring-opening of the rhodamine derivative generating orange fluorescence and bright pink colouration. The sensing system was efficiently utilized for fluorimetric detection and imaging of orthosilicic acid accumulation in-vitro in human kidney cells (HK cells). To the best of our knowledge, this is the first time this sensing system (Rh1@TiO2) is reported for detection of toxic silica species accumulation in-vitro in human kidney cells. The advantages, such as good water dispersibility, the absence of organic solvents during fluorimetric studies, quick turn-on type signal transduction, low-level imaging, which are offered by the synthesized sensing material (Rh1@TiO2), make it a potential candidate to fabricate medical tool for early identification of silicainduced nephrotoxicity, which can help to reduce the burden and risk of chronic kidney disease development.

Au (Core)–Pt (Shell) Nanocatalysts with the Shell Thickness Controlled at a Monolayer Level: Extremely High Activity for Hydrogen Peroxide Decomposition

Au and Pt nanoparticle-loaded anatase TiO2 particles (Au/TiO2 and Pt/TiO2) were separately prepared by the deposition–precipitation method. Also, selective Pt photodeposition on the Au surface of Au/TiO2 yielded Au (core)–Pt (shell) bimetallic NP-loaded TiO2 particles. In Au (core)–Pt (shell)/TiO2, the mean Pt-shell thickness was controlled at an atomic layer level by irradiation time. The thermocatalytic activities of Au/TiO2, Pt/TiO2, and Au (core)–Pt (shell)/TiO2 for the decomposition of H2O2 were evaluated in the dark at 25 °C. Au (core)–Pt (shell)/TiO2 exhibits a much higher activity than that of Au/TiO2 and even Pt/TiO2 in spite of that Pt has the highest activity among the metals. The turnover frequency depends on the mean number of Pt layers, reaching a maximum of 1.1 × 106 around the monolayer. Density functional theory simulations were performed to analyze the potential-energy surfaces in metal-cluster-catalyzed H2O2 decomposition with Au50, Pt50, and Au14 (core)–Pt36 (shell) used as model metal...

One-step hydrothermal synthesis and characterisation of SnO2 nanoparticle-loaded TiO2 nanotubes with high photocatalytic performance under sunlight

The enhancement of the photocatalytic activity of TiO2 nanotubes (TNTs), as a result of heterojunction formation through the addition of SnO2 nanoparticles (NPs) by a simple and straightforward one-step hydrothermal method, is shown. The structure and properties of the as-synthesised composite material are characterised using X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, UV–Vis diffuse reflectance spectroscopy, Raman spectroscopy and photoluminescence spectroscopy. The SnO2/TNT heterojunction with extremely small SnO2 NPs adhered on the TNT surface was successfully synthesised by a one-step hydrothermal synthesis. The mechanism and factors affecting the photocatalytic activity were verified and clarified. Furthermore, the sample with 2% SnO2 precursor content has the highest photocatalytic activity with a methylene blue degradation efficiency of 74.2% for 180 min under sunlight irradiation.

Incorporation of the polarization point on the graphene aerogel to achieve strong dielectric loss behavior

The preparation of nanocomposites of reduced graphene oxide with loaded TiO2 nanoparticles (TRGO) by a facile one-step hydrothermal treatment is reported. We have successfully increased the contact area of TiO2 and RGO to enhance polarization point, which is in favor of strengthening interfacial polarization. The interfaregioncial polarization has been regarded as an important role on the attenuation of high-frequency electromagnetic waves. Therefore, a good absorber is prepared by inserting the polarization point on the graphene aerogel, which shows excellent electromagnetic wave absorbing properties. In detail, the minimum reflection loss value at 2.1mm is up to −27.2dB for the TRGO-1.5 composite and the frequency bandwidth of 5.2GHz can be obtained. Thus, it demonstrates that the adjustment of interface polarization would play a key role in the microwave-absorbing ability.

Silver-loaded nanotubular structures enhanced bactericidal efficiency of antibiotics with synergistic effect in vitro and in vivo.

Antibiotic-resistant bacteria have become a major issue due to the long-term use and abuse of antibiotics in treatments in clinics. The combination therapy of antibiotics and silver (Ag) nanoparticles is an effective way of both enhancing the antibacterial effect and decreasing the usage of antibiotics. Although the method has been proved to be effective in vitro, no in vivo tests have been carried out at present. Herein, we described a combination therapy of local delivery of Ag and systemic antibiotics treatment in vitro in an infection model of rat. Ag nanoparticle-loaded TiO2 nanotube (NT) arrays (Ag-NTs) were fabricated on titanium implants for a customized release of Ag ion. The antibacterial properties of silver combined with antibiotics vancomycin, rifampin, gentamicin, and levofloxacin, respectively, were tested in vitro by minimum inhibitory concentration (MIC) assay, disk diffusion assay, and antibiofilm formation test. Enhanced antibacterial activity of combination therapy was observed for all the chosen bacterial strains, including gram-negative Escherichia coli (ATCC 25922), gram-positive Staphylococcus aureus (ATCC 25923), and methicillin-resistant Staphylococcus aureus (MRSA; ATCC 33591 and ATCC 43300). Moreover, after a relative short (3 weeks) combinational treatment, animal experiments in vivo further proved the synergistic antibacterial effect by X-ray and histological and immunohistochemical analyses. These results demonstrated that the combination of Ag nanoparticles and antibiotics significantly enhanced the antibacterial effect both in vitro and in vivo through the synergistic effect. The strategy is promising for clinical application to reduce the usage of antibiotics and shorten the administration time of implant-associated infection.

Streptomycin loaded TiO2 nanoparticles: preparation, characterization and antibacterial applications

We report a facile synthesis of Titanium dioxide (TiO2) nanoparticles by sol gel technique assisted by biogenic route using the rind of Aloevera and demonstrate the antibacterial assessment against human pathogens causing urinary tract infection. The synthesized nanoparticles were characterized by powder XRD analysis, FT-IR analysis and scanning electron microscopic analysis. The XRD spectrum confirmed that the synthesized TiO2 nanoparticles exhibit anatase phase. Average grain size was calculated using Debye–Scherrer formula and it was found to decrease from 13 to 8 nm with increasing template concentration. FTIR spectrum showed characteristic bands at 1626, 1056 and 1074 cm−1 revealing C–N stretching of amino groups present in the protein cages of Aloevera which assist in the formation of TiO2 nanoparticles. Morphological characterization analyzed by SEM showed nanocoral network and all the networks displayed excellent invitro bioactivity against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella typhi and Proteus mirabilis. Drug delivery was assessed by the release of anti-inflammatory streptomycin which is evidenced by the release profile suggesting that it has the potential to provide better deliveries.

Gold‐Nanoparticle‐Loaded Carbonate‐Modified Titanium(IV) Oxide Surface: Visible‐Light‐Driven Formation of Hydrogen Peroxide from Oxygen

Gold nanoparticle-loaded rutile TiO2 with a bimodal size distribution around 10.6 nm and 2.3 nm (BM-Au/TiO2 ) was prepared by the deposition precipitation and chemical reduction (DP-CR) technique. Visible-light irradiation (λ>430 nm) of the BM-Au/TiO2 plasmonic photocatalyst yields 35 μm H2 O2 in aerated pure water at irradiation time (tp )=1 h, and the H2 O2 concentration increases to 640±60 μm by the addition of 4 % HCOOH as a sacrificing electron donor. Further, a carbonate-modified surface BM-Au/TiO2 (BM-Au/TiO2 -CO3 (2-) ) generates a millimolar level of H2 O2 at tp =1 h with a quantum efficiency (Φ) of 5.4 % at λ=530 nm under the same conditions. The recycle experiments confirmed the stable performance of BM-Au/TiO2 .