V. Rajendar

Novel synthesis and structural analysis of zinc oxide nanoparticles for the non enzymatic glucose biosensor

A non-enzymatic glucose biosensor was developed by utilizing the zinc oxide nanoparticles (ZnO NPs) synthesized by a novel green method using the leaf extract of Ocimum tenuiflorum. The structural, optical and morphological properties of ZnO NPs characterized by means of X-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDAX) spectroscopy, and transmission electron microscopy (TEM). The XRD analysis revealed that the ZnO NPs were crystalline and had a hexagonal wurtzite structure. The crystallite size measured by XRD was the same as that measured using SEM and TEM. The UV-vis absorption spectrum estimates the band gap of ZnO NPs present in the range of 2.82 to 3.45eV. The reduction and formation of ZnO NPs mainly due to the involvement of leaf extract bio-molecular compounds analyzed from the FTIR spectra. The SEM result confirms the morphology of the NPs responsible from the various concentration of leaf extract in the synthesis process. HRTEM analysis depicts the spherical structure of ZnO NPs. The synthesized NPs have the average size ranges from 10 to 20nm. The fabricated GCE/ZnO glucose sensor represents superior electro catalytic activity that has been observed for ZnO NPs with a reproducible sensitivity of 631.30μAmM-1cm-2, correlation coefficient of R=0.998, linear dynamic range from 1-8.6mM, low detection limit of 0.043μM (S/N=3) and response time<4s.

Novel synthesis and characterization of pristine Cu nanoparticles for the non-enzymatic glucose biosensor

Non enzymatic electrochemical glucose sensing was developed based on pristine Cu Nanopartilces (NPs)/Glassy Carbon Electrode (GCE) which can be accomplished by simple green method via ocimum tenuiflorum leaf extract. Then, the affect of leaf extract addition on improving Structural, Optical and electrochemical properties of pristine cu NPs was investigated. The synthesized Cu NPs were characterized with X-ray diffraction (X-ray), Uv–Visible spectroscopy (Uv–Vis), Fourier transformation infrared spectroscopy (FTIR), Particle size distribution (PSA), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS), Transmission electron microscopy (TEM) for structural optical and morphological studies respectively. The synthesized Cu NPs were coated over glassy carbon electrode (GCE) to study the electrochemical response of glucose by cyclic voltammetry and ampherometer. The results indicates that the modified biosensor shows a remarkable sensitivity (1065.21 μA mM−1 cm−2), rapid response time (<3s), wide linear range (1 to 7.2 mM), low detection limit (0.038 μM at S/N = 3). Therefore, the prepared Cu NPs by the Novel Bio-mediated route were exploited to construct a non-enzymatic glucose biosensor for sustainable clinical field applications.Graphical Abstract

Nanostructured conducting polyaniline (NSPANI)/CeO2 nanocomposites for humidity sensors application

This paper reports the electrochemical activity of nanostructured conducting polyaniline (NSPANI) whose properties were enhanced by adding inorganic ceria (CeO2) nanoparticles that has excellent electro catalytic ability and biocompatibility properties. The method of synthesis employed for the nanocomposites of NSPANI and Cerium oxide (CeO2) was by in-situ polymerization method with different weight percentage of cerium oxide in aniline monomer. The metal oxide CeO2 nanoparticles were prepared by co-precipitation method. The effects of addition of ceria in weight percentage of 10, 20, 25 and 30 were investigated by various characterization techniques like X-ray diffraction, functional groups by Fourier Transform Infrared Spectroscopy, Thermal stability by Thermal Gravimetric Analysis, Morphology by Scanning Electron Microscope and Transmission electron microscope. Application of NSPANI/CeO2 nanocomposites in the field of humidity sensors were studied where different weight percentages of the CeO2 in aniline were compared along with the NSPANI without ceria. The material that showed the maximum sensitivity and also good linearity was the nanocomposite of NSPANI with 20% ceria.

Enhanced antimicrobial and anticancer properties of ZnO and TiO2 nanocomposites

The study describes the antibacterial and anticancer activities of a nanocomposite prepared by mixing zinc oxide and titanium dioxide nanoparticles. The particle mixtures were analyzed by X-ray diffraction, Field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and dynamic light scattering techniques. Thus, analyzed samples were subject to disc diffusion method at various concentrations to analyze their antibacterial activities against two Gram-positive and two Gram-negative bacteria. The same samples were then analyzed for their anticancer activities on four different cell lines. The results indicate a synergistic effect of the nanocomposite on both antibacterial and anticancer properties when compared to their individual counterparts.