Green Synthesis of Co3O4 Nanorods for Highly Efficient Catalytic, Photocatalytic, and Antibacterial Activities.

Cobalt oxide nanorods were successfully synthesized by a hot plate combustion method using the plant extract of Vitis vinifera. The plant extract as an alternative to toxic chemicals can be used generally as reducing and capping agents. The obtained nanorods were characterized by XRD, FT-IR, Raman, TEM, SAED, EDX, DRS, PL and VSM techniques for the structural, morphological, optical and magnetic properties. The XRD, FT-IR, Raman, EDX analysis confirmed the high purity of the sample. The TEM and SAED results showed the rod shape morphology of the sample. DRS and PL showed the band gap energy and emission at visible region. VSM showed the antiferromagnetic nature of the sample. The photocatalytic activities of the as-prepared cobalt oxide nanorods were investigated for the degradation of textile dying waste water. As per the standards of Indian pollution control board for industrial waste water let out into river bodies, the degradation reactions of waste water was found to be 250 mg/L at 150 min. Also, the same catalyst is used for the reduction of 4-nitrophenol and 4-nitroaniline using sodium borohydride as a reducing agent and it exhibits excellent reduction reaction, because of the high active surface sites. The time taken for the reduction reaction was 300 sec and 210 sec for 4-nitrophenol and 4-nitroaniline respectively. Also, the antibacterial activities towards the bacterial strains were studied and reported.

Perusal on the role of DMF solvent and hydrogen bonding in the formation of 1D polymeric chains in mixed ligand Ni(II) complex as an anticancer agent: a computational approach.

A novel mixed ligand Ni(II) metal complex has been investigated for the modification in structural conformation, coordination bond, and noncovalent interactions. The novel Ni(II) metal complex [Ni(TFPB)2(1,10-Ph)(DMF)] has been synthesized and structurally characterized, which featured six coordination with three bidentate ligands connected through oxygen and nitrogen atoms. The single-crystal X-ray analysis showed that the compound possessed octahedral geometry and C-H…F, C-H…O, and π…π intermolecular interactions resulting in the formation of supramolecular architecture contributed significantly towards the crystal packing and molecular stability. Hirshfeld surface analysis was carried out to validate various intermolecular interactions. Further, the 3D structural topologies were visualized using energy framework analysis. To explore the coordination stability and chemically reactive parameters of the novel Ni(II) complex, the electronic structure was optimized using density functional theory calculations. The natural bond orbital analysis revealed the various hyperconjugative interactions exhibited by the complex. In addition, the complex was screened for in silico studies to understand the antitumoricidal potential of the novel Ni(II) complex. Molecular docking studies were also performed against three targeted proteins (PDB ID: 6H0W, 6NE5, and 6E91) to investigate the binding mode and protein-ligand interactions. These results are further analyzed by molecular dynamic simulation to confirm the best possible interactions and stability in the active site of the targeted proteins with a simulation period of 100 ns.Communicated by Ramaswamy H. Sarma.

Preparation and Characterization of Mg Doped ZnAI2O4Spinel Nanoparticles.

In the present study, combustion technique is adopted to study the impact of Mg2+ ion doping on ZnAI2O4 nanoparticles (NPs). L-arginine is used as a fuel component. The Mg2+ ions play a pivotal role in persuading various characteristics of ZnAI2O4 NPs. Various characterization technqiues such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), high resolution scanning electron microscopy (HR-SEM), diffuse reflectance spectroscopy (DRS), Thermo-gravimetric/differential thermal analysis (TG-DTA) and vibrating sample magnetometer (VSM) were carried out in order to synthesize the nanoparticles. Single phase cubic spinel structure of ZnAl2O4 (gahnite) formation was confirmed from the XRD characterization process of the nanoparticles. Estimated average crystallite size range of 11.85 nm to 19.02 nm was observed from Debye-Scherrer. Spherical morphology with uniform distributions was observed from HR-SEM characterization images. From the band gap studies, the attained band gap values were found to lie within 5.41 eV-4.66 eV range. The ZnAl2O4 and Mg:ZnAl2O4 NPs exhibited super-paramagnetic nature confirmed by magnetic measurements. The obtained results make ZnAl2O 4and Mg:ZnAl2O4 NPs appropriate for various optical, catalytic, energy and data storage applications.

Developing green sonochemical approaches towards the synthesis of highly integrated and interconnected carbon nanofiber decorated with Sm2O3 nanoparticles and their use in the electrochemical detection of toxic 4-nitrophenol.

Highly integrated and interconnected carbon nanofiber hybrid nanofibers decorated with samarium(III) oxide (Sm2O3 NPs) nanoparticles was synthesized by ultrasound assisted method and characterized using X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), energy dispersive x-rays (EDX), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The electrocatalytic activity (ECA) was monitored by detection of toxic 4-nitrophenol under phosphate buffer (pH 7.0). The sonochemical route employed was efficient to prepare Sm2O3 NPs modified electrode and this class of catalysts might be active electrocatalyst for the detection of 4-nitrophenol in drinking water. The screen-printed carbon electrode (SPCE) modified with Sm2O3 NPs@f-CNFs was fabricated in a facile way for the sensitively electrochemical determination of 4-nitrophenol. Under optimized preparation conditions, the electrochemical testing (differential pulse voltammetry) of 4-nitrophenol exhibited a reduction peak at -0.64 V. Compared with bare SPCE, Sm2O3 NPs, f-CNFs, Sm2O3 NPs@f-CNFs modified SPCE showed highest current response. The reduction peaks current vs the concentration of 4-nitrophenol exhibits a linear relation with the concentration range from 0.02 to 387.2 µM and the limit of detection was determined to be M (S/N = 3). In addition, Sm2O3 NPs@f-CNFs was contributed to detecting 4-nitrophenol in drinking water and river water samples with the recover ranging from 95.6% to 98.2%.

Facile synthesis of copper sulfide decorated reduced graphene oxide nanocomposite for high sensitive detection of toxic antibiotic in milk.

The development of an effective technique for detecting antibiotic drugs remains a serious task due to their toxicity to public health. For this purpose, herein, we report an electrochemical detection based on Cu2S nanosphere decorated reduced graphene oxide (RGO@Cu2S NC) nanocomposite. A sonochemical-assisted method was adopted to prepare the nanocomposite. Subsequently, its morphological, elemental, and crystal structural aspects were analysed. The electrochemical properties were examined in order to ensure the material's suitability in electrocatalytic sensing. RGO@Cu2S NC affixed screen-printed electrode was found to exhibit tremendous electrocatalytic capability toward chloramphenicol (CAP) reduction. A sensitive and reproducible amperometric CAP sensor was fabricated which was able to detect concentration at the nanomolar level. The method worked well even in real samples (fresh milk samples) and the results are evaluated by HPLC method and amperometric methods.

Ultrasound-assisted synthesis of α-MnS (alabandite) nanoparticles decorated reduced graphene oxide hybrids: Enhanced electrocatalyst for electrochemical detection of Parkinson's disease biomarker.

Herein, novel manganese sulfide nanoparticles (MnS NPs) decorated reduced graphene oxide (rGOS) nanocomposite have been designed through a facile ultrasound-assisted method and followed by a sonication process. After then, as-synthesized α-MnS@rGOS was characterized by HRTEM, FESEM, XPS, XRD and EIS. Furthermore, the α-MnS@rGOS nanocomposite modified SPCE (screen-printed carbon electrode) shows excellent electrochemical sensing performance towards Parkinson's disease biomarker of dopamine (DA). Moreover, the fabricated sensor showed a wide linear range for dopamine between 0.02 and 438.6 µM and nanomolar detection limit (3.5 nM). In addition, the α-MnS@rGOS modified SPCE showed selectivity towards the detection of dopamine in presence of a 10-fold higher concentration of other important biomolecules. The nanocomposite film modified SPCE sensor was good stable and reproducible towards the detection of Parkinson's disease biomarker. Furthermore, the as-synthesized α-MnS@rGOS nanocomposite modified SPCE has been applied to the determination of dopamine in human serum, rat serum and pharmaceutical samples with acceptable recoveries.

Facile synthesis of mesoporous WS2 nanorods decorated N-doped RGO network modified electrode as portable electrochemical sensing platform for sensitive detection of toxic antibiotic in biological and pharmaceutical samples.

We report a facile and ultrasound assisted sonochemical synthesis of a Tungsten disulfide nanorods decorated nitrogen-doped reduced graphene oxide based nanocomposite. The WS2 NRs/N-rGOs nanocomposite was characterized by FESEM, HRTEM, XRD, XPS and electrochemical methods and its application towards the electrochemical detection of organo-arsenic drug (coccidiostat). The WS2 NRs/N-rGOs modified SPCE was used for the electrochemical reduction of roxarsone (ROX) and it showed superior electrocatalytic performance in terms of reduction peak current and shift in overpotential when compared to those of WS2 NRs/SPCE, N-rGOs/SPCE and based SPCE. The WS2 NRs/N-rGOs modified SPCE showed an excellent sensing ability towards ROX in nitrogen saturated phosphate buffer (PB) then the other controlled modified and unmodified electrodes. The WS2 NRs/N-rGOs/SPCE displays high sensitive response towards ROX and gives wide linearity in the range of 0.1-442.6 µM ROX in neutral phosphate buffer (pH 7.0) and the sensitivity of the sensor is calculated as 14.733 µA µM-1 cm-2. The WS2 NRs/N-rGOs nanocomposite modified sensor also exhibits valuable ability of anti-interference to electroactive analytes. Furthermore, the as-prepared WS2 NRs/N-rGOs/SPCE has been applied to the determination of ROX in biological and pharmaceutical samples.

A novel electrochemical sensor for determination of DNA damage biomarker (8-hydroxy-2'-deoxyguanosine) in urine using sonochemically derived graphene oxide sheets covered zinc oxide flower modified electrode.

To explore a novel and multi-layer based graphene oxide covered zinc oxide nanoflower (ZnO NFs@GOS) as a modified electrode materials by sonochemical technique (40 kHz, 300 W). Herein, novel nanocomposite is successfully characterized by various characterization analysis (FESEM, HRTEM, XRD, XPS and (EIS) electrochemical impedance spectroscopy) and employed as high sensitive modified electrode (ZnO NFs@GOS nanocomposite) for the electrochemical determination of biomarker. 8-hydroxy-2'-deoxyguanosine (8-HDG) is one of the important cancer and oxidative stress biomarker. The results demonstrated that the ZnO NFs@GOS modified SPCE reveal well-defined electro-oxidation peak at 0.36 V (vs. Ag/AgCl). The high sensitive properties of the optimized flower like modified electrode are because of the excellent synergistic effect of the ZnO flower and the graphene oxide nanosheets, as evidenced by a superior bio-sensing performance. The nanocomposite fabricated modified biosensor was facilitating the analysis of 8-HDG in the concentration ranges of 0.05-536.5 µM with a low detection limit is 8.67 nM. The ZnO NFs@GOS modified sensor can also employed for the determination of 8-HDG in human urine samples, promising its application towards the quantification of cancer biomarker in biological samples.

One-pot sonochemical synthesis of Bi2WO6 nanospheres with multilayer reduced graphene nanosheets modified electrode as rapid electrochemical sensing platform for high sensitive detection of oxidative stress biomarker in biological sample.

4-Nitroquinoline N-oxide (4-NQO) is an important tumorigenic organic compound with high adverse effect in the human body. In this study, a novel Bismuth Tungstate nanospheres (Bi2WO6) decorated reduced graphene oxide (Bi2WO6/rGOS) nanocomposite have been designed through a sonochemical method. The as-synthesized Bi2WO6/rGOS was characterized through the HRTEM, FESEM, XPS, EIS and XRD. Furthermore, the nanocomposite modified glassy carbon electrode (GCE) was developed for the determination of 4-NQO. The results showed that the Bi2WO6/rGOS nanocomposite modified electrode exhibit valuable responses and excellent electrocatalytic activity. The fabricated sensor was facilitated the analysis of 4-NQO with a nanomolar detection limit (6.11 nM). Further, the as-synthesized Bi2WO6/rGOS modified electrode has been applied to sensing of 4-NQO in human blood and urine samples with satisfactory recovery.

Facile sonochemical synthesis of perovskite-type SrTiO3 nanocubes with reduced graphene oxide nanocatalyst for an enhanced electrochemical detection of α-amino acid (tryptophan).

In this paper, perovskite-type SrTiO3 nanocubes decorated reduced graphene oxide is synthesized by sonochemical method. The as-synthesized SrTiO3@RGO nanocomposite was confirmed by XRD, TEM, SEM, elemental mapping and electrochemical technique. Furthermore, surface morphological and X-ray diffraction studies revealed the formation and high loading of SrTiO3 nanocubes on reduced graphene oxide matrix. The SrTiO3@RGO nanocomposite modified electrode shows an excellent electrochemical detection towards of amino acid (tryptophan). The developed sensor was showed a wide linear range from 30 nM to 917.3 µM and detection limit is 7.15 nM. Furthermore, the sensitivity was calculated to be 9.11 µA µM-1 cm2. In addition, the proposed modified sensor is exhibited good selectivity, stability, reproducibility and repeatability. The SrTiO3@RGO catalyst modified electrode was successfully applied to tryptophan analysis in biological samples.

A novel nanocomposite with superior electrocatalytic activity: A magnetic property based ZnFe2O4 nanocubes embellished with reduced graphene oxide by facile ultrasonic approach.

Herein, a novel Zinc Ferrite nanocubes (ZnFe2O4 NCs) decorated reduced graphene oxide (rGO) nanocomposite have been designed through a sonochemical method. After then, as-synthesized ZnFe2O4 NCs/rGO was characterized by XPS, XRD, HRTEM and EIS. Furthermore, the ZnFe2O4 NCs/rGO nanocomposite modified GCE (glassy carbon electrode) shows excellent electrochemical sensing performance towards biomarker of 4-nitroquinoline N-oxide (4-NQ) with fast detection. 4-NQ is one of the important cancer biomarker. Moreover, the fabricated sensor showed a wide linear window for 4-NQ between 0.025 and 534.12 µM and nanomolar detection limit (8.27 nM). Further, the as-prepared ZnFe2O4 NCs/rGO/GCE has been applied to the determination of 4-NQ in human blood and urine samples with excellent recovery results.

Green synthesis of NiO nanoparticles using Aegle marmelos leaf extract for the evaluation of in-vitro cytotoxicity, antibacterial and photocatalytic properties.

In the present study, we report the green synthesis of NiO nanoparticles using Aegle marmelos as a fuel and this method is ecofriendly and cost effective. The plant Aegle marmelos is used in the field of pharmaceuticals to cure diseases like chronic diarrhea, peptic ulcers and dysentery in India for nearly 5 centuries. The as-prepared nanoparticles were confirmed as pure face centered cubic phase and single crystalline in nature by XRD. The formation of agglomerated spherical nanoparticles was shown by HR-SEM and HR-TEM images. The particle size calculated from HR-SEM was in the range 8-10 nm and it matches with the average crystallite size calculated from the XRD pattern. NiO shows intense emission peaks at 363 and 412 nm in its PL spectra. The band gap of 3.5 eV is observed from DRS studies and the formation of pure NiO is confirmed by FT-IR spectra. The as-prepared NiO nanoparticles show super paramagnetic behavior, when magnetization studies are carried out. It is then evaluated for cytotoxic activity towards A549 cell culture, antibacterial activity and photocatalytic degradation (PCD) of 4­chlorophenol (4­CP), which is known as the endocrine disrupting chemical (EDC). From the results, it is found that the cell viability of A549 cells was effectively reduced and it showed better antibacterial activity towards gram positive bacterial strains. It is also proved to be an efficient and stable photocatalyst towards the degradation of 4­CP.

Green synthesis of Ag nanoparticles using Tamarind fruit extract for the antibacterial studies.

In the present study, first time we report the microwave-assisted green synthesis of silver nanoparticles (AgNPs) using Tamarindus indica natural fruit extract. The plant extract plays a dual role of reducing and capping agent for the synthesis of AgNPs. The formation of spherical shape AgNPs is confirmed by XRD, HR-SEM, and HR-TEM. The presence of face-centered cubic (FCC) silver is confirmed by XRD studies and the average crystallite size of AgNPs is calculated to be around 6-8nm. The average particle diameter is found to be around 10nm, which is identified from HR-TEM images. The purity of AgNPs is confirmed by EDX analysis. The presence of sigmoid curve in UV-Visible absorption spectra suggests that the reaction has complicated kinetic features. To investigate the functional groups of the extract and their involvement in the reduction of AgNO3 to form AgNPs, FT-IR studies are carried out. The redox peaks are observed in cyclic voltammetry in the potential range of -1.2 to +1.2V, due to the redox active components of the T. indica fruit extract. In photoluminescence spectroscopy, the excited and emission peaks were obtained at 432nm and 487nm, respectively. The as-prepared AgNPs showed good results towards antibacterial activities. Hence, the present approach is a facile, cost- effective, reproducible, eco-friendly, and green method.

Studies on the efficient dual performance of Mn1-xNixFe2O4 spinel nanoparticles in photodegradation and antibacterial activity.

The present work describes the successful synthesize of spinel magnetic ferrite Mn1-xNixFe2O4 (x=0.0, 0.1, 0.2, 0.3, 0.4 & 0.5) nanoparticles via a simple microwave combustion method which was then evaluated for its photocatalytic activity in the degradation of indigo carmine (IC) synthetic dye, a major water pollutant. Our results reveal that the synthesized of Ni2+ doped MnFe2O4 nanoparticles possess well-crystalline pure cubic spinel phase, exhibit excellent optical and magnetic properties. Further, the photocatalytic performance of the synthesized nanoparticles at different concentration ratios of Ni2+ ions was monitored by photocatalytic degradation of indigo carmine synthetic dye under UV (λ=365nm) light irradiation. In order to get maximum photocatalytic degradation (PCD) efficiency, we have optimized various parameters, which include catalyst dosage, initial dye concentration, pH and Ni2+ dopant content. It was found that the reaction was facilitated with optimum catalyst dose of 50mg/100mL, high dye concentrations of 150mg/L and acidic pH and among all the synthesized samples, Mn0·5Ni0.5Fe2O4 exhibit superior performance of photocatalytic activity on the degradation of indigo carmine synthetic dye. These results highlighted the potential use of effective, low-cost and easily available photocatalysts for the promotion of wastewater treatment and environmental remediation. In addition, the antibacterial activity of spinel magnetic Mn1-xNixFe2O4 nanoparticles against two Gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two Gram negative bacteria (Pseudomonas aeruginosa and Escherichia coli) was also examined. Our antibacterial activity results are comparable with the results obtained using the antibiotic, streptomycin.