ABSTRACT
Carbon nanotubes (CNTs) are still receiving much attention in bio-sensing applications due to their remarkable properties. In this present research work, fibre-like carbon nanotubes (f-CNTs) were successfully fabricated over copper-molybdenum (Cu-Mo) substituted alumina nanoparticles at atmospheric pressure by chemical vapor deposition (CVD) technique and effectively employed as a neurotransmitter dopamine (DA) sensor. The obtained product was purified and structurally characterized by various techniques such as, field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, high resolution transmission electron microscope (HRTEM) and X-ray photoelectron spectroscopy (XPS) analysis. Structural characterization, which reveals the material contains fibre-like multi walled carbon nanotubes with graphene layers having diameter in the range of 10-20 nm and 200-300 nm inner and outer, respectively and has certain crystallinity. The weight percentages of Cu, Mo in Alumina catalyst, reaction temperature, acetylene flow rate and reaction time have been optimised to yield maximum of carbon product. Electrochemical properties of the material towards DA sensing were studied by cyclic voltammetry (CV), and diffuse pulse voltammetry (DPV) techniques. The sensor exhibits linear relationship among the peak current and DA concentration from 8 to 45 µM with detection limit of 5.3 µM (S/N = 3). The presence of structural analogues of DA has no deleterious effect on the DA anodic peak current.
ABSTRACT
Bimetal oxide ZnO-MgO nanoparticles were synthesised by precipitation method at low temperature and characterised by analytical techniques such as XRD, SEM and FT-IR. In order to know the efficiency of uptake and release of anticancer drug, the adsorption and release of doxorubicin, on bimetal oxide nanoparticles was performed in dark room at room temperature. The adsorption models such as Henry, Freundlich and Langmuir models were validated with obtained experimental data. Due to heterogeneous surface of bimetal oxides, data followed well with Henry and Freundlich models but not Langmuir that proposed homogeneous adsorbent surface. The strong affinity between drug and nanoparticles is certainly due to the electrostatic interaction between positively charged doxorubicin molecules and negatively charged surface of ZnO-MgO nanoparticles and hydrogen bonding between them that confirmed from FT-IR analysis. The doxorubicin release from ZnO-MgO nanoparticles was performed at pH 4 and 7 to evaluate the kinetic of drug release using various mathematical models. At neutral pH, the doxo release was found to be ~14% whereas at acidic pH (pH 4) nearly 68% of doxo was released at 6.5 hours due to dissolution and neutralising the surface charge of ZnO-MgO nanoparticles. Various mathematical models such as zero order, first order, Higuchi and Hixson-Crowell were approached to evaluate the kinetic release of drug from the nanoparticles. The obtained release data for acidic pH followed Hixson-Crowell model, proposes erosion dependent release system, compared to Higuchi that confirmed doxo release is due to dissolution of ZnO-MgO nanoparticles. In this study, it is concluded that ZnO-MgO nanoparticles will be a promising drug vehicle in drug delivery system.
Subject(s)
Doxorubicin/chemistry , Magnesium Oxide/chemistry , Metal Nanoparticles/chemistry , Models, Chemical , Nanocapsules/chemistry , Zinc Oxide/chemistry , Adsorption , Antibiotics, Antineoplastic/chemistry , Antineoplastic Agents/chemistry , Body Fluids/chemistry , Computer Simulation , Diffusion , Hydrogen-Ion Concentration , Kinetics , Materials Testing , Metal Nanoparticles/ultrastructure , Nanocapsules/ultrastructure , Particle Size , Surface PropertiesABSTRACT
A new method of graphene oxide (GO) synthesis via single-step reforming of sugarcane bagasse agricultural waste by oxidation under muffled atmosphere conditions is reported. The strong and sharp X-ray diffraction peak at 2θ = 11.6° corresponds to an interlayer distance of 0.788 nm (d002) for the AB stacked GOs. High-resolution transmission electron microscopy (HRTEM) and selected-area electron diffraction (SAED) confirm the formation of the GO layer structure and the hexagonal framework. This is a promising method for fast and effective synthesis of GO from sugarcane bagasse intended for a variety of energy and environmental applications.
