Biocomposites Containing Silver Nanoparticles for Biomedical Applications

Journal of Cluster Science - Clinically, implant-related bone infections are a serious concern as they reduce the success rate of grafting techniques and increases the risk of morbidity. Clinicians...     

Studies on Structural,Optical, Thermal and Electrical Properties of Perylene-Doped p-terphenyl Luminophors

A simple solid state reaction technique was employed for the preparation of polycrystalline luminophors of p-terphenyl containing different amounts of perylene followed by spectral characterization techniques viz. XRD, SEM, TGA-DSC, UV–Visible spectroscopy, thermo-electrical conductivity, fluorescence spectroscopy, fluorescence life time spectroscopy and temperature dependent fluorescence. X-ray diffraction profiles of the doped p-terphenyl reveal well-defined and sharp peaks indicate homogeneity and crystallinity. The SEM micrograph of pure p-terphenyl exhibit flakes like grains and then compact and finally gets separately with perylene amounts. The observed results indicate that closed packed crystal structures of doped p-terphenyl during crystal formation. The band gaps estimated from UV–visible spectroscopy decreased from 5.20 to 4.10 eV, while thermo-electrical conductivity increases with perylene content. The fluorescence spectra showed partial quenching of p-terphenyl fluorescence and simultaneously sensitization of perylene fluorescence at the excitation wavelength of p-terphenyl (290 nm) due to excitation energy transfer from p-terphenyl to perylene. The observed sensitization results are in harmony with intense blue color seen in fluorescence microscopy images and has high demand in scintillation process.     

Efficient maximization of coloration by modification in morphology of electrodeposited NiO thin films prepared with different surfactants

In this paper, we report on the nickel oxide (NiO) thin films potentiostatically electrodeposited onto indium-doped tin oxide-coated glass substrates by using two types of organic surfactants: (1) non-ionic: polyethylene glycol (PEG), polyvinylpyrrolidone (PVP) and (2) anionic: sodium dodecyl sulfate (SDS). An aqueous solution containing nickel sulfate precursor and potassium hydroxide buffer was used to grow the samples. The effect of organic surfactants on its structural, morphological, wettability, optical, electrochromic, and in situ colorimetry were studied using X-ray diffraction, scanning electron microscopy, contact angle, FT-IR spectroscopy, optical transmittance, cyclic voltammetry, and CIE system of colorimetry. X-ray diffraction patterns show that the films are polycrystalline, consisting of NiO cubic phase. A nanoporous structure with pore diameter of about 150–200 nm was observed for pure NiO. The films deposited with the aid of organic surfactants exhibits various surface morphological feature. PVP-mediated NiO thin film shows noodle-like morphology with well-defined surface area whereas, an ordered pore structure composed of channels of uniform diameter of about 60–80 nm was observed for PEG. A compact and smooth surface with nanoporous structure stem from SDS helps for improved electrochromic performance compared with that of NiO deposits from surfactant-free solution. Wetting behavior shows, transformation from hydrophilic to superhydrophilic nature of NiO thin films deposited with organic surfactant, which helps for much more paths for electrolyte access. The surfactant-mediated NiO produce high color/bleach transmittance difference up to 57% at 630 nm. On oxidation of NiO/SDS, the CIELAB 1931 2° color space coordinates show the transition from colorless to the deep brown state (L* = 84.41, a* = −0.33, b* = 4.41, and L* = 43.78, a* = 7.15, b* = 13.69), with steady decrease in relative luminance. The highest coloration efficiency of 54 cm² C⁻¹ with an excellent reversibility of 97% was observed for NiO/SDS thin films.     

FRET Between Riboflavin and 9-Anthraldehyde Based Fluorescent Organic Nanoparticles Possessing Antibacterial Activity

The aqueous suspension of fluorescent nanoparticles were prepared by using 9-anthradehdye derivative (AH). The nanoparticles (AHNPs) were characterized using DLS-zeta sizer and SEM techniques. The photo physical properties of nanoparticles and precursor were measured and compared using UV-absorption spectroscopy, fluorescence spectroscopy and fluorescence lifetime studies. The significant overlap between fluorescence spectrum of AHNPs and excitation spectrum of Riboflavin (RF) led us to explore Fluorescence Resonance Energy Transfer (FRET) studies between AHNPs and RF in aqueous medium. The mechanism of FRET from AHNPs to RF discussed on spectral observations, thermodynamic parameters and changes produces in fluorescence lifetime in absence and presence of different concentrations of RF to AHNPs. The limit of detection for RF (0.071 µM) is considerably low compared with reported methods. Thus, we explore AHNPs as novel nano probe for quantitative determination of RF in pharmaceutical samples based on FRET study. In addition with this, AHNPs has excellent antibacterial activity than the bulk material for two different bacteria culture viz. E. coli and Bacillus sps.

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Graphical Abstract 9-anthradehdye based fluorescent nanoparticles (AHNPs) explores as nano probe to detect Riboflavin (RF) in aqueous medium based on Fluorescence Resonance Energy Transfer (FRET) studies. The proposed analytical method successfully applied for quantitative determination of RF in pharmaceutical samples. In addition, with this, AHNPs has excellent antibacterial activity than the bulk material for two different bacteria culture suspension viz. E. coli and Bacillus sps.