Abstract: In this study, we report the synthesis and characterization studies of amine functionalized CoFe2O4 and NiFe2O4 nanoparticles (NPs). The synthesis process was accomplished by refluxing metal chloride precursors in ethylene glycol in presence of sodium acetate and ethanolamine. The average crystallite sizes of the synthesized particles are found to be in the range of 8-10 nm. The synthesized particles are characterized using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) technique, FTIR, Raman and UV-visible spectroscopy for crystal structure, average size, surface area, phase and functional group determination. The surface morphology and elemental composition were studied by Scanning electron microscope (SEM) and X-ray fluorescence (XRF) respectively. Magnetic behavior upto fields of 3T at room temperature measured in PPMS magnetometer showed the superparamagnetic behavior of these particles. Analysis of cytotoxicity was carried out by examining their effect on cell viability of human peripheral blood lymphocytes so as to assess biocompatibility for various biomedical applications.
Abstract: In this paper, we report the experimental observations of the effects of Ni concentration on the structural and magnetic properties of NixZn1-xFe2O4 (x=0.2-0.8) ferrite nanoparticles synthesized by a chemical method via a polymer precursor. The synthesis process involves a reaction of aqueous solutions of metal salts (Fe3+, Zn2+ and Ni2+) with an aqueous poly-vinyl alcohol (PVA)-sucrose solution at 65-70oC. Controlled growth of the ferrite nanoparticles was achieved by encapsulation of the nucleating sites in the PVA-sucrose polymer micelles. Structural properties of the derived samples were analyzed with X-ray diffraction (XRD) and X-ray absorption near edge spectroscopy (XANES) studies. The magnetic properties of the NixZn1-xFe2O4 (x=0.2-0.8) nanoparticles were evaluated at room temperature with a vibrating sample magnetometer (VSM). XRD analysis confirmed the formation of single phase cubic spinel ferrite structure. The local structural analysis of the Ni-Zn ferrite crystal system performed with XANES studies at Fe K-edge revealed the migration of Fe3+ ions from the octahedral sites to tetrahedral sites with the increase in Ni2+concentration in the ferrite structure.It was observed that the magnetization increases with the increase in Ni concentration till the maximum saturation magnetization was observed in the composition Ni0.5Zn0.5Fe2O4. Further increase in Ni concentration reduces the magnetization. The obtained results were analyzed in correlation with the cationic distributions at the lattice sites in these ferrite nanoparticles.
Abstract: In this paper, we have studied theoretically the effect of bimetallic silver/ gold layer on sensitivity of the graphene based surface plasmon resonance (SPR) biosensor. Here, silver layer (instead of chromium and titanium) is used as an adhesive layer in between gold and BK7 glass prism. The optimized thickness of silver/gold layers reported in literature has been used for the analysis of various sensitivity parameters of the biosensor. A computational simulation is performed to analyze the nature of plasmon dip shift with respect to the addition of graphene layer and binding layer respectively.
Abstract: One dimensional rutile-TiO2 nanoneedles (NNs) and nanorods (NRs) were grown directly on transparent conductive Fluorine-doped SnO2-coated (FTO) glass substrates using Chemical Bath Deposition (CBD) method. Titanium (III) chloride was used as the precursor, followed by annealing at 200°C. The heat treatment leads to the conversion of TiO2 nanoneedles into nanorods. Optical studies revealed that rutile-TiO2 thin films have a high absorption coefficient and a direct bandgap which decreased slightly (3.14-3.09 eV) by applying heat treatment .The ease of deposition of rutile-TiO2 nanocomposite with different morphologies at low temperature provides a new insight for potential applications in solar cells, sensors, catalysis and separation technology.
Abstract: Breast cancer is the second leading cause of cancer death in women all over the world. Despite advanced treatment modalities, the systemic toxicity remains a major side effect resulting into patient morbidity and mortality. Recently, natural products are being targeted for drug discovery because of their major role in cancer prevention and treatment. Plants have been the main source of natural compounds that are being used in medicine. However, most of the herbal bioactives are hydrophobic in nature resulting into their limited bioavailability and in turn their therapeutic efficacy. To overcome this problem, different nanocarriers such as nanoparticles, nanocapsules, liposomes, quantum dots, phytosomes, dendrimers and nanoemulsions have been conjugated with anticancer herbal bioactives. Such nanochemotherapeutic agents exhibit increased bioavaibility, enhanced pharmacological activity and stability with reduced systemic toxicity. While majority of the reviews focus upon herbal loaded nanoformulations for various biological applications, this report is an attempt to particularly highlight the potential of nanotechnology in the delivery of herbal bioactives for breast cancer management.
Abstract: Multi-walled Carbon Nanotubes (MWCNTs) have a great potential for microelectronics, optics and in biomedical applications (e.g. as nanoelectrodes for neural stimulation and functional scaffolds for tissue engineering). In order to understand the interactions of MWCNTs with the human body on a whole, it is important to know how they interact with the cells. In this study, we dispersed the MWCNTs with anionic surfactant, characterized the properties of dispersed MWCNTs, and then evaluated the uptake of MWCNTs by A549 lung epithelial cells using Confocal Raman spectroscopy.
Abstract: Tuberculosis is still a major global health concern, causing the estimated death of 1.5 million people per year and being associated with high morbidity. The development of point-of-care diagnostic tools for tuberculosis is mandatory, especially because the fast and accurate detection of the slow-growing Mycobacterium tuberculosis by the conventional diagnostic tests is difficult.The objective of this work was to develop the first steps to achieve a portable method for the diagnosis of tuberculosis, by a sandwich-immunoassay combined with magnetoresistive biochip technology.With the purpose of conjugating 250 nm streptavidin-coated magnetic nanoparticles with anti- M. tuberculosis biotinylated antibodies, Mycobacterium bovis Bacillus Calmette-Guérin was used as a surrogate for M. tuberculosis bacteria. After magnetic capture, target bacteria were brought in contact with the surface of the magnetoresistive biochip previously functionalized with a secondary anti-M. tuberculosis antibody. Magnetically labeled cells were detected by an array of spin-valve sensors, which change their electrical resistance in the presence of the fringe field of the magnetic particles. Optimization studies on the efficiency of the magnetic capture and further recognition of the bacteria by the secondary antibody on the biochip surface were conducted. The results on the magnetoresistive biochip showed a clear difference in the signal between specific and control (non-specific) sensors, suggesting the usefulness of this technique as a potential biorecognition tool for the development of a point-of-care diagnostic method for tuberculosis.
Abstract: In this work, a comparative study using atomic force microscopy (AFM) and field emission–scanning electron microscopy (FESEM) has been carried out to assess the morphology of single cell Escherichia coli bacteria (E-coli). E-coli bacteria are a major concern for public health. Attention was focused on the certain strains of E-coli bacteria, because some strains can be toxic and cause food poisoning. The E-coli bacteria have attracted much research interest because this bacterium is easily to get, cheap and rapid reproductively. Imaging of E-coli recently, was improved by using high resolution microscopy. Current techniques for detection such as, AFM and FESEM has attracted great interest and emerging as a potentially powerful whole-organism fingerprinting tool for the rapid identification of bacteria. The obtained results of AFM and FESEM techniques have been compared to show the image quality of single cell E-coli.
Abstract: Ferroelectric-relaxor behavior on highly epitaxial Barium Zirconium Titanate (Ba (Zr0.2Ti0.8)O3) thin film was investigated using the Piezoresponse Force Microscopy specifically to investigate the onset of relaxor behavior. The surface roughness, microstructure and the grain size of the film were systematically studied. Ferroelectric switching at random localized points were observed at room temperature though it has been previously reported that the phase transition in BZT-20 occurs at 285K. Phase reversal with the reversal of the applied voltage was also seen. Scanning Capacitance Microscope has been employed to interrogate the localized change in the capacitance with change in voltage. The thin film sample showed the presence of ferroelectric nanoregions at room temperature unlike its bulk counterparts which is paraelectric at room temperature.