Showing papers by "Badiadka Narayana published in 2020"

Fabrication and characterization of conductive silk fibroin–gold nanocomposite films

Abstract: This research proposes a one-step fabrication of novel conducting silk fibroin (SF) nanocomposites (NCs) in which in situ generation of nanoparticles from their precursor are achieved. Here, the gold salt (HAuIIICl4·H2O) is reduced to gold nanoparticles (AuNPs) using SF, a renewable natural biopolymer, and SF–AuNPs NCs are developed via solution casting method. The optical absorption spectra recorded using the UV–Visible spectroscopy (UV–Vis) witnesses the generation of anisotropic particles by showing two absorption bands. Also, the calculated optical band gap energy (Eg) value decreases from 4.2 to 2.4 eV with the increasing concentration of AuNPs. The X-ray diffraction (XRD) profile of the NCs confirms the presence of AuNPs. The scanning electron microscopy (SEM) micrographs clearly admit the successful formation of AuNPs in the host polymer matrix with homogeneous dispersion. The size and evolution of the different shaped AuNPs are confirmed by the transmission electron microscopy (TEM) study. An increase in DC conductivity from 1.48 × 10−9 to 7.12 × 10−9 S/cm and decrease in frequency-dependent dielectric constant are observed with the increase in AuNPs. The obtained result suggests that the insulating behaviour of the SF can be effectively changed into a conducting nature with the in situ creation of AuNPs in the SF matrix.

Phase segregation induced third order nonlinear saturable absorption behavior in Erbium doped ZnO nanoparticles synthesized by facile hydrothermal method

Abstract: Here in this work, we present the dominance of rare earth dopant (Er) in association with the surfactant (Oleylamine) on the structural, surface morphology, optical, and nonlinear optical properties of hydrothermally grown ZnO nanoparticles. The polycrystalline nature of the prepared nanostructures is confirmed by the XRD diffractograms. The formation of erbium related compound (erbium oxide) in the highest Er doped ZnO nanoparticles is visible from the XRD diffractogram. The incorporation of Er at different doping concentrations (1 at. wt.%, 3 at. wt.%, and 5 at. wt.%) brings noticeable morphological changes in the FESEM images. The Raman spectra reveal the retention of wurtzite structure in undoped and Er doped nanoparticles. The disappearance of A1 (TO) mode in ZnEr3 and ZnEr5 nanoparticles shows the deteriorated polar lattice bond strength. The phase segregation observed from XRD spectrum of ZnEr5 nanoparticles is further confirmed by the detection of local vibrational mode (LVM). A severe decrement in the bandgap of the Er doped nanoparticles is noticed from UV–Vis spectroscopy. A continuous fall in the intensity in the NBE emission with increasing Er doping concentration is attributed to the formation of surface defects below the conduction band edge. The nonlinear optical parameters of the nanoparticles are quantified with the assistance of open aperture and closed aperture Z-scan curves. A remarkable switching from reverse saturable absorption (RSA) to saturable absorption (SA) and self-defocusing to self-focusing mechanisms in ZnEr5 shed light on the impact of phase segregation on the nonlinear response of the Er doped nanoparticles. The quantified values of nonlinear parameters look promising in the fabrication of photonic devices.

Understanding reactivity of a triazole derivative and its interaction with graphene and doped/undoped-coronene-a DFT study.

Abstract: In the present study, 4-[(E)-(2-chorobenzylidene)amino]-3-(2-chlorobenzyl)-1H-1,2,4-triazole-5(4H)-thione (CAC) was characterized by spectroscopic investigations. The complete vibrational assignmen...

A highly selective chemosensor derived from benzamide hydrazones for the detection of cyanide ion in organic and organic-aqueous media: design, synthesis, sensing and computational studies

Abstract: A new, highly sensitive and selective chemosensing method has been developed for the detection of cyanide ion using benzamide hydrazone receptors (R1-R4). The sensing ability of these compounds tow...

Facile fabrication of silk fibroin microparticles: their characterization and potential adsorption study

Abstract: Silk fibroin (SF) microparticles were fabricated by blending of SF solution with hydroxyl propyl methyl cellulose (HPMC), and the SF/HPMC blend films were prepared using simple solvent evaporation

Nitrate/Nitrite determination in water and soil samples accompanied by in situ azo dye formation and its removal by superabsorbent cellulose hydrogel

Abstract: In the present work, an efficient method is developed for the spectrophotometric determination of nitrite and nitrate ions in water and soil samples by in situ formation of azo dye (Griess reagent) which showed λmax at 385 nm The reaction condition and the concentration of reagents used are optimized The molar absorptivity, Sandell’s sensitivity, detection limit and quantification limit of the method are found to be 322 × 104 L mol−1 cm−1, 198 × 10−6 µg cm−2, 00030 µg mL−1 and 00092 µg mL−1 respectively with the linearity range up to 26 µg mL−1 The formation of azo dye is confirmed by 1H and 13C Nuclear Magnetic Spectroscopy The azo dye formed during the determination is effectively removed using custom made ecofriendly cellulose modified hydrogel in order to reduce organic load in the test samples The structure, morphology and the thermal properties of hydrogel are determined by Fourier-transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis respectively The dye removal mechanism involves pseudo second order kinetics, adsorption is found to be spontaneous based on the thermodynamic parameters and it is befitting to Freundlich isotherm model

Silk fibroin and silk fibroin-gold nanoparticles nanocomposite films: sustainable adsorbents for methylene blue dye

Abstract: In this paper, the preparation of silk fibroin (SF) and silk fibroin-gold nanoparticles (SF-AuNPs) nanocomposites (NC) and their adsorbability of methylene blue (MB) dye is reported. SF is used in ...

Photo-Driven Synthesis of Anisotropic Gold Nanoparticles Using Silk Fibroin—Cell Viability Activities in Lymphocyte and Jurkat Cancer Cells

Abstract: A simple, environmentally benign and low-cost method for the synthesis of different-shaped gold nanoparticles using silk fibroin (SF) under ultraviolet (UV-B) radiation has been reported in this work. No additives such as organic solvents, surfactants, external reducing, stabilizing agents or high temperature were used for the synthesis of the particles. SF acts as a reducing and subsequently, stabilizing agent. The UV-Visible (UV-Vis) absorption spectra support the formation of different-shaped gold nanoparticles by displaying transverse and longitudinal surface plasmon bands at different wavelengths. The size and shape evolution of the nanoparticles was studied using the transmission electron microscope (TEM) to confirm the formation of different-shaped particles. Nano-crystalline structure and FCC crystal family of gold were confirmed by X-ray diffraction (XRD) measurement study. Furthermore, the proliferative activities of the synthesized colloidal gold nanoparticles were tested against lymphocyte and Jurkat cancer cell lines. The obtained results proved that the biogenic different-shaped AuNPs showed better activity in comparison with the spherical-shaped gold nanoparticles.

Molecular Docking of 4-ethoxychalcones on Oxidoreductase/Pirin Inhibitors and Cytotoxic Evaluation on Breast/Skin Cancer Cell Lines

Abstract: The role of α, β unsaturated propenone derivatives, has attracted the chemists for its biological importance. An attempt is made to reveal the interaction between breast and skin cancer cell lines with the help of molecular docking studies. The study aimed to synthesize and characterize 4-ethoxychalcones for testing breast and skin cancer targets. A series of chalcone analogues starting from 4-ethoxyacetophenone and substituted aromatic aldehydes were synthesized, well-characterized and evaluated for their in vitro anticancer activities against human breast cancer (MDA-MB-231) and human metastatic melanoma (A-375) cell lines by MTT assay. Docking simulation was performed to study the drug-receptor interaction of chalcone scaffold on the active site of target inhibitor bound to cytochrome P450 family oxidoreductase for breast cancer and Pirin inhibiting target for skin cancer, respectively. After performing cytotoxic evaluation, it was observed that compounds having a substitution at the para position showed better results compared to ortho and meta positions for both the cell lines. Molecular docking studies revealed different types of interactions with selected oxidoreductase and Pirin inhibiting targets. Ligand-protein interactions and morphological changes are monitored by molecular dynamics. The presence of electron-withdrawing and donating groups on ring B marginally affected IC50 and docking scores. The stability of the binding mode of ligands having high inhibitory efficiency for compounds 8 and 10 predicted by docking studies was confirmed by molecular dynamics simulation. The pharmacokinetic parameters were found to be within the acceptable range. Further molecular dynamics study would provide the necessary information.

Design, Synthesis, Docking and Computational Pharmacokinetic Profiling of New Pyrazolinyl Thiazolinone Biheterocycles as Potent Antimicrobial Agents

Abstract: Development of potential antimicrobial agents is the main aim in the drug discovery process to overcome the problem of drug resistance. Pyrazolines and thiazolinones are extensively used as building blocks for the synthesis of diverse and medicinally important compounds. In this present work, a new series of functionalized pyrazolinyl-thiazolinone biheterocycles is designed and synthesized from N-pyrazolinecarbothioamide. Antimicrobial screening is carried out in order to discover their potential towards six bacterial and four fungal strains. The zone of inhibition (ZI in mm) was determined by the disc diffusion method and minimum inhibitory concentration (MIC in μg/mL) by macro dilution method. The druggability of these new entities is done through in silico pharmacokinetic profiling using Maestro 2017-1 interface of Schrӧdinger software. Compounds 4c and 4e with chloro and iodo substituents on Nphenylacetamide ring displayed good inhibitory antibacterial activity against the tested bacterial strains with minimum MIC values when compared to the reference drug tetracycline. Compound 3 with an acetic acid derivative showed high antifungal activity among all the tested derivatives. Compound 3 not only showed antifungal activity but also qualified druggability test with no violation of Lipinski rule of five. The capability of the synthesized pyrazolinyl-thiazolinone derivatives was performed to efficiently inhibit the growth of microorganisms against selected bacterial and fungal strains. Further, these compounds are found to be effectively bound to the active sites of attractive target Escherichia coli FabH.