Formation of ZnO nanorods via low temperature hydrothermal method for enzymatic glucose sensor

In this study, zinc oxide (ZnO) nanorod arrays were synthesized using a simple hydrothermal reaction on a ZnO seeds/ITO substrate and applied for the fabrication of enzymatic glucose sensor. ZnO nanorod matrix provided a favourable environment for the immobilization of glucose oxidase (GOx) and introduced a shuttling way for electronic communication between GOx and electrode. The performance of different aspect ratio of ZnO nanorods that was produced by varying hydrothermal reaction time was studied. The aspect ratio of ZnO influenced the GOx enzyme immobilization. The morphology and structure of prepared ZnO nanorods were characterized by employing scanning electron microscopy (SEM), and X-ray powder diffraction (XRD). Electrochemical measurements of the sensor showed a reproducible sensitivity of 2.06 μA/cm2mM for ZnO matrix grown for 4 h with the aspect ratio of 8.0

Study of ITO Glass Electrode Modified with Iron Oxide Nanoparticles and Nafion for Glucose Biosensor Application

AbstractIn this study, we report the fabrication of the indium tin oxide (ITO) glass electrode modified with iron oxide nanoparticles (IONPs) and nafion for glucose biosensor applications. The IONPs was synthesized using the precipitation method and functionalized with citric acid (CA) to provide hydrophilic surface and functional group for glucose oxidase (GOx) enzyme immobilization. The structural and morphological studies of CA-IONPs were characterized using X-ray diffractometer (XRD) and transmission electron microscope (TEM). The size of the IONPs measured from TEM image was ∼17nm. The bioelectrode designated as Nafion/GOx/CA-IONPs/ITO was developed by drop casting of the CA-IONPs, GOx and nafion on the ITO glass. The Nafion/GOx/CA-IONPs/ITO bioelectrode showed good electrochemical performance for glucose detection. The functionalized CA-IONPs acted as the catalyst and help to improve the electron transfer rate between GOx and ITO electrode. In addition, thin nafion film was coated on the electrode to prevent interference and improve chemical stability. The Nafion/GOx/CA-IONPs/ITO bioelectrode showed high sensitivity of 70.1μAmM-1cm-2 for the linear range of 1.0-8.0mM glucose concentrations

Seed-Mediated Growth Of Gold Nanorods For Diagnostic Applications.

This work describes properties of gold nanorods synthesized using a seed-mediated method

Properties of Ce-doped Bi0.5Na0.5TiO3 Synthesized using the Soft Combustion Method

AbstractIn this work, bismuth sodium titanate (BNT) and cerium (Ce)-doped BNTwere successfully synthesized using the soft combustion method. The effect of 3, 5, and 7 mol% Ce, respectively added as dopant on stoichiometry, microstructure, density and dielectric properties were studied. Pure BNT phase was obtained in the sample containing 3 mol% Ce after calcination at 800°C for 3h. The calcined powders were then pressed into pellets and sintered at 1100°C for 3h. The grain size of the pellets decreased with the addition of Ce3+ because Ce acted as a grain growth inhibitor. Maximum density was obtained in 3 mol% Ce-doped BNT, and decreased with increasing amount of Ce dopant. In addition, the maximum dielectric constant of 468.35 was obtained in 3 mol% Ce-doped BNT and decreased at higher amount of Ce doping. The addition of Ce as a dopant in BNT also decreased the dielectric loss

Applying the Taguchi Method to Optimise the Size of Silica Nanoparticles Entrapped with Rifampicin for a Drug Delivery System

The aim of this study was to optimise the experimental conditions for the synthesis of silica nanoparticles. In achieving this, the amount of butanol, the amount of surfactant, the amount of silica precursor, the synthesis temperature and the agitation speed were optimised by applying the Taguchi orthogonal arrays method. The optimal synthesis conditions for silica nanoparticle production were a temperature of 50°C, 6 ml butanol, 7 ml Tween 80, 3 ml trimethoxyvinylsilane (TMVS), and an agitation speed of 320 rpm. The nanoparticle size was characterised to optimise the synthesis conditions and determined to be smaller than 100 nm using a Malvern Zetasizer Nano ZS and a transmission electron microscope (TEM)

Overview of the main methods used to combine proteins with nanosystems: absorption, bioconjugation, and encapsulation

The latest development of protein engineering allows the production of proteins having desired properties and large potential markets, but the clinical advances of therapeutical proteins are still limited by their fragility. Nanotechnology could provide optimal vectors able to protect from degradation therapeutical biomolecules such as proteins, enzymes or specific polypeptides. On the other hand, some proteins can be also used as active ligands to help nanoparticles loaded with chemotherapeutic or other drugs to reach particular sites in the body. The aim of this review is to provide an overall picture of the general aspects of the most successful approaches used to combine proteins with nanosystems. This combination is mainly achieved by absorption, bioconjugation and encapsulation. Interactions of nanoparticles with biomolecules and caveats related to protein denaturation are also pointed out. A clear understanding of nanoparticle-protein interactions could make possible the design of precise and versatile hybrid nanosystems. This could further allow control of their pharmacokinetics as well as activity, and safety

Evaluation of Bismuth Oxide Nanoparticles as Radiosensitizer for Megavoltage Radiotherapy

Metal-based nanoparticles such as gold, silver, platinum, and bismuth have been widely investigated for radiotherapeutic application. Basic understanding of the cellular interaction of the nanoparticles with the biological materials is crucial to ensure future clinical use. In this study, the cytotoxicity, cellular uptake, and generation of reactive oxygen species (ROS) induced by BiONPs were investigated prior elucidating the feasibility of BiONPs for radiotherapy application using megavoltage photon and electron beams. The BiONPs of diameter sizes 60, 70, 80 and 90 nm at concentrations within a range of 0.5 to 0.00005 mMol/L were tested on MCF-7, MDA-MB-231, and NIH/3T3 cells lines. The cytotoxicity results exhibit minimal cell death constituting less than 20 % of mortality on average. The ROS generation by BiONPs alone is found to be negligible as the ROS levels were slightly lower and higher than 100% of positive control. The increment of cellular nanoparticles uptake from a range of 1.50 % to 34.10 % indicates that BiONPs were internalized and bound to the surface of the cells. Sequencing from the results, 60 nm BiONPs are found to be the most suitable to be applied as a radiosensitizer in radiotherapy. Sensitization enhancement ratio (SER) quantified on MCF-7 cells demonstrated the highest enhancement from the highest concentration of BiONPs with SER of 2.29 and 1.42, for 10 MV photon beam and 6 MeV electron beam, respectively. In contrast to ROS production without radiation, the ROS induced from radiotherapy beams were found to be dose-dependent and play significant roles in radiosensitization effect. In conclusion, BiONPs could improve clinical radiotherapy, and further radiobiological characterization is crucial for future clinical translation

Sensitive and selective detection of chloroform by current-voltage using ZnO nanorods modified electrode

The development of in situ chloroform detection is crucial due to the high risk of carcinogenic effects associated with chloroform exposure. In this study, an electrochemical-based chloroform sensor was fabricated using undoped ZnO nanorods on indium tin oxide (ZnONRs/ITO) electrode to detect chloroform in aqueous-phase samples. Based on the results, the FESEM imaging showed that the ZnONRs exhibited an evenly distributed circular structure with a diameter of 62-90 nm, while the EDX and XRD findings confirmed the presence of Zn and O elements deposited on the electrode surface. Furthermore, the phosphate buffer solution (PBS) solution significantly affected the performance of the modified electrode with an optimal concentration and pH of 0.1 M and pH 7. The results also highlighted the vital function of the modified ZnONRs/ITO electrode as an efficient electron mediator and its catalytic potential to induce chloroform oxidation. Most importantly, the modified ZnONRs/ITO electrode was able to detect the presence of chloroform in real seawater samples, where the repeatability and reproducibility tests achieved a Relative Standard Deviation (RSD) of 1.41% and 2.61%, respectively, indicating the exceptional performance of the modified electrode. Moreover, the modified ZnONRs/ITO electrode recorded a low limit of detection and high sensitivity of 1.50 μM and 2.11 μA/cm2·mM, respectively, within a 0.010-10 mM linear dynamic range. In conclusion, the current-voltage (I-V) method proved the reliable, satisfactory, and effective fabrication of the modified ZnONRs/ITO electrode for chloroform sensing in aqueous-phase samples, including in real seawater samples