Characterization of a conjugate between poly(N-vinyl caprolactam) and a triazine-based covalent organic framework as a potential biomaterial.

Thermoresponsive polymers (TRPs) have been explored over decades for biomedical applications, and poly(N-vinylcaprolactam) (PVCL) TRP is extensively investigated due to its low toxicity and lower critical solution temperature (LCST), close to physiological temperatures. Besides this, the utilization of covalent organic frameworks (COFs), which belong to a class of porous polymers, in bio-based applications is of great interest due to their remarkable properties. Thus, the integration of PVCL and covalent organic frameworks (COFs) as conjugate materials can lead to advanced bio-based applications; however, the need is to understand the influence of the COF on the PVCL conformation. Herein, a triazine-based COF, CC-TAPT-COF, has been synthesized and completely characterized. Later, the effect of CC-TAPT-COF on the PVCL polymer conformation was studied using various techniques. In fluorescence spectroscopy, a fluorescence quenching for PVCL in the presence of CC-TAPT-COF was observed, which indicated conformational changes. Later, results from thermal fluorescence studies and dynamic light scattering as a function of temperature showed a slight decrease in LCST value for PVCL after the addition of CC-TAPT-COF concentrations. These results showed a slight effect of CC-TAPT-COF on the PVCL conformation. Likewise, a slight decrease in the transmittance value for specific bands in infrared spectra showed a slight effect of CC-TAPT-COF on the PVCL conformation. Further, results from electron microscopy and atomic force microscopy revealed a conjugate formation between PVCL and CC-TAPT-COF due to the presence of binding interactions between them. Overall, the results from several studies showed a slight effect of CC-TAPT-COF on the PVCL during conjugate formation between PVCL and CC-TAPT-COF. This study will be beneficial for the development of COF-thermoresponsive polymer conjugates with a mixture of their unique features as advanced biomaterials.

Biocompatibility assessment of chemically modified GONRs with hemoglobin and histopathological studies for its toxicity evaluation.

Transition metal-Schiff base complexes are found to be important for biomedical applications but have demerits of being homogeneous complexes, thus their synthesis on the surface of graphene oxide nanoribbons (GONRs), materials of specific interest, can be beneficial for preparing advanced graphene-based materials for biomedical applications. Of foremost importance is their safety and biocompatibility with biological systems. In this study, a transition metal-Schiff base complex has been synthesized on the surface of a GONR (Ni-S-GNR) using 3-aminopropyltriethoxysilane and pyridine-2-carbaldehyde and complexing nickel. This Ni-S-GNR was characterized well by various physicochemical techniques. The evaluation of biocompatibility of Ni-S-GNR with hemoglobin confirmed binding interactions and influence on the native structure of hemoglobin. It was found that there was alteration in the secondary and tertiary structures of hemoglobin. In addition, histopathological studies on the liver and kidney cells of rats revealed non-toxicity of Ni-S-GNR towards these cells. Overall, Ni-S-GNR was found to be compatible with protein as the native structure was not destroyed and was non-toxic to cells.

Biosynthesized δ-Bi2O3 Nanoparticles from Crinum viviparum Flower Extract for Photocatalytic Dye Degradation and Molecular Docking.

Bioinspired delta-bismuth oxide nanoparticles (δ-Bi2O3 NPs) have been synthesized using a greener reducing agent and surfactant via co-precipitation method. The originality of this work is the use of Crinum viviparum flower extract for the first time for the fabrication of NPs, which were further calcined at 800 °C to obtain δ-Bi2O3 NPs. Physicochemical studies such as FTIR spectroscopy and XPS confirmed the formation of Bi2O3 NPs, whereas XRD and Raman verified the formation of the cubic delta (δ) phase of Bi2O3 NPs. However, HRTEM revealed the spherical shape with diameter 10-20 nm, while BET studies expose mesoporous nature with a surface area of 71 m2/gm. The band gap for δ-Bi2O3 NPs was estimated to be 3.45 eV, which ensured δ-Bi2O3 to be a promising photocatalyst under visible-light irradiation. Therefore, based on the results of physicochemical studies, the bioinspired δ-Bi2O3 NPs were explored as active photocatalysts for the degradation of toxic dyes, viz., Thymol blue (TB) and Congo red (CR) under visible-light irradiation. The study showed 98.26% degradation of TB in 40 min and 69.67% degradation of CR in 80 min by δ-Bi2O3 NPs. The photogenerated holes and electrons were found responsible for this enhancement. Furthermore, molecular docking investigations were also performed for δ-Bi2O3 NPs to understand its biological function as New Delhi metallo-ß-lactamase 1 (NDM-1) [PDB ID 5XP9] enzyme inhibitor, and studies revealed good interaction with various amino acid residues and found good hydrogen bonding with a fine pose energy of -3.851 kcal/mole.

Bioinspired NiO Nanospheres: Exploring In Vitro Toxicity Using Bm-17 and L. rohita Liver Cells, DNA Degradation, Docking, and Proposed Vacuolization Mechanism.

The present work demonstrated a novel Cleome simplicifolia-mediated green fabrication of nickel oxide nanoparticles (NiO NPs) to explore in vitro toxicity in Bm-17 and Labeo rohita liver cells. As-fabricated bioinspired NiO NPs were characterized by several analytical techniques. X-ray diffraction (XRD) revealed a crystalline face-centered-cubic structure. Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) confirmed NiO formation. The chemical composition was confirmed by energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy. Brunauer-Emmett-Teller (BET) revealed the mesoporous nature. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the formation of 97 nm diameter nanospheres formed due to the congregation of 10 nm size particles. Atomic force microscopy (AFM) revealed the nearly isotropic behavior of NiO NPs. Further, a molecular docking study was performed to explore their toxicity by binding with genetic molecules, and it was found that the docking energy was about -9.65284 kcal/mol. On evaluating the in vitro toxicity of NiO NPs for Bm-17 cells, the study showed that when cells were treated with a high concentration of NPs, cells were affected severely by toxicity, while at a lower concentration, cells were affected slightly. Further, on using 50 µg/mL, quick deaths of cells were observed due to the formation of more vacuoles in the cells. The DNA degradation study revealed that NiO NPs are significantly responsible for DNA degradation. For further confirmation, trypan blue assay was observed for cell viability, and morphological assessment was performed using inverted tissue culture microscopy. Further, the cytotoxicity of NiO NPs in L. rohita liver cells was studied. No toxicity was observed at 1 mg/L of NiO NPs; however, when the concentration was 30 and 90 mg/L, dark and shrank hepatic parenchyma was observed. Hence, the main cause of cell lysis is the increased vacuolization in the cells. Thus, the present study suggests that the cytotoxicity induced by NiO NPs could be used in anticancer drugs.

Extended Release of Metronidazole Drug Using Chitosan/Graphene Oxide Bionanocomposite Beads as the Drug Carrier.

This study depicts the facile approach for the synthesis of chitosan/graphene oxide bionanocomposite (Chi/GO) beads via the gelation process. This is the first-ever study in which these Chi/GO beads have been utilized as a drug carrier for the oral drug delivery of metronidazole (MTD) drug, and investigations were made regarding the release pattern of the MTD drug using these Chi/GO beads as a drug carrier for a prolonged period of 84 h. The MTD is loaded on the surface as well as the cavity of the Chi/GO beads to result in MTD-Chi/GO bionanocomposite beads. The MTD drug loading was found to be 683 mg/g. Furthermore, the in vitro release patterns of pure drug and the drug encapsulated with Chi/GO beads are explored in simulated gastric as well as simulated intestinal fluids with phosphate-buffered saline (PBS) of pH 1.2 and 7.4, respectively. As-synthesized bionanocomposite beads have shown excellent stability and capacity for extended release of the MTD drug as compared to the pure drug in terms of bioavailability in both media. The cumulative release data are fitted with the Korsmeyer-Peppas kinetics and first-order reaction kinetics at pH 1.2 and 7.4. The synthesized bionanocomposite beads have good potential to minimize the multiple-dose frequency with the sustained drug release property and can reduce the side effects due to the drug.

Transition-metal complexes of group 12 with 1,1'-bis(phosphanyl)ferrocene ligands.

The syntheses of four new cadmium and zinc complexes with 1,1'-bis(phosphanyl)ferrocene ligands and their phosphine chalcogenide derivatives are reported. The complexes were characterized by elemental analyses and IR, 1H NMR, 31P NMR and electronic absorption spectroscopy. The crystal structures of dichlorido[1-diphenylphosphinoyl-1'-(di-tert-butylphosphanyl)ferrocene-κ2O,P]cadmium(II), [CdCl2{(C17H14OP)(C13H22P)Fe}] or CdCl2(κ2P,O-dppOdtbpf) (1), bis[µ-(tert-butyl)(1'-diphenylphosphinoylferrocen-1-yl)phosphinato-κ3O,O':O'']bis[chloridozinc(II)], [Zn2{(C9H13O2P)(C17H14OP)Fe}2Cl2] or [ZnOCl{κ2O,O'-Ph2POFcPO2(t-Bu)}]2 (2), 1,1'-bis(di-tert-butylthiophosphinoyl)ferrocene, [Fe(C13H22PS)2] or dtbpfS2 (3), and [1,1'-bis(dicyclohexylphosphanyl)ferrocene-κ2P,P'][chlorido/cyanido(0.25/1.75)]zinc(II), [Zn(CN)1.75Cl0.25{(C17H26P)2Fe}] or Zn(CN)2(κ2-dcpf) (4), were determined crystallographically. Compound 1 has tetrahedral geometry in which the CdII centre is coordinated by one dppOdtbpf ligand in a κ2-manner and by two Cl atoms, while compound 2 displays a centrosymmetric dimeric unit in which two oxide atoms bridge the two Zn atoms to generate an eight-membered ring. Compound 3 revealed a sandwich structure with both phosphane groups sulfurized. In compound 4, the ZnII atom adopts a tetrahedral geometry by coordinating to the 1,1'-bis(dicyclohexylphosphanyl)ferrocene ligand in a κ2-manner and to two cyanide ligands.

Sustainable Synthesis of MOF-5@GO Nanocomposites for Efficient Removal of Rhodamine B from Water.

Herein, a metal-organic framework (MOF-5) is synthesized by a solvothermal process and graphene oxide (GO) is prepared from the improved Hummer's method. The synthesis of MOF-5@GO nanocomposites is one-pot process via a grinding method and employed for the removal of Rhodamine B (RhB) dye. The removal efficiency of RhB is found to be 60.64% (151.62 mg·g-1) at 500 ppm. About 98.88% of RhB is removed within 5 min of contact time and increased up to 99.68% up to 10 min. The removal rate of MOF-5@GO nanocomposites is much better than that of pristine MOF-5. Equilibrium adsorption capacity is determined by a series of different experimental conditions such as pH, time, and concentration of dye solution. Although the results also showed that dye removal on MOF-5@GO nanocomposites is well described by the Langmuir isotherm (R 2 = 0.9703), the adsorption kinetics data reveals pseudo-second-order (R 2 = 0.9908). The synthesized nanocomposite is efficient for removal of dye, cost-effective, and reusable. Additionally, stability and self-degradation studies of pure RhB are reported in aqueous solution for up to 120 days at different pH values (pH 1-12).

Protein immobilization on graphene oxide or reduced graphene oxide surface and their applications: Influence over activity, structural and thermal stability of protein.

Due to the essential role of biological macromolecules in our daily life; it is important to control the stability and activity of such macromolecules. Therefore, the most promising route for enhancement in stability and activity is immobilizing proteins on different support materials. Furthermore, large surface area and surface functional groups are the important features that are required for a better support system. These features of graphene oxide (GO) and reduced graphene oxide (RGO) makes them ideal support materials for protein immobilization. Studies show the successful formation of GO/RGO-protein complexes with enhancement in structural/thermal stability due to various interactions at the nano-bio interface and their utilization in various functional applications. The present review focuses on protein immobilization using GO/RGO as solid support materials. Moreover, we also emphasized on basic underlying mechanism and interactions (hydrophilic, hydrophobic, electrostatic, local protein-protein, hydrogen bonding and van der Walls) between protein and GO/RGO which influences structural stability and activity of enzymes/proteins. Furthermore, GO/RGO-protein complexes are utilized in various applications such as biosensors, bioimaging and theranostic agent, targeted drug delivery agents, and nanovectors for drug and protein delivery.

Evaluation of Utilizing Functionalized Graphene Oxide Nanoribbons as Compatible Biomaterial for Lysozyme.

Graphene oxide nanoribbons with superior physicochemical properties acquired from graphene and carbon nanotubes have been used in various applications including biomedical applications. For biomedical applications, it is of utmost importance to understand how these graphene oxide nanoribbons interact with proteins and the influence they have on protein conformation and function. In this regard, an attempt has been made to evaluate the utility of graphene oxide nanoribbons as a compatible biomaterial for lysozyme (Lys) protein. In this study, graphene oxide nanoribbons (GONRs) synthesized from multiwalled carbon nanotubes (MWCNTs) were first functionalized with (3-aminopropyl)triethoxysilane (APTES) and further modified with vanillin (Val) to obtain Val-APTES-GONRs. On characterization, it was found that the Val-APTES-GONRs material had a ribbonlike morphology with abundant functionalities for interaction with protein. On evaluation of Val-APTES-GONRs as a compatible biomaterial for Lys, studies revealed that a lower concentration of the as-synthesized material has less influence on the conformation and the structure of Lys with better activity, whereas higher concentrations of the as-synthesized material had a greater influence on conformation and the structure of Lys with decreased activity. Overall, the thermal stability of Lys was maintained after introducing the Val-APTES-GONRs material. In addition, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) and Raman spectroscopies were performed for Lys composites with Val-APTES-GONRs for further understanding biomolecular interactions. This study is beneficial for designing advanced graphene-based materials for numerous bioinspired applications and better biomaterials for biotechnological use.

Ruthenium oxide nanoparticles immobilized over Citrus limetta waste derived carbon material for electrochemical detection of hexestrol.

Hexestrol is a non-steroidal estrogen which causes carcinogenic effects in animals. It is therefore important to develop sensitive and selective test methods for its early detection. Herein, we report the development of an electrochemical sensor to detect hexestrol in ultralow concentrations. In order to devise a simple and cost-effective hexestrol sensing electrode, attention is paid to the development of biomass-derived porous carbon (PCB) with large surface area and suitable porosity to immobilize ruthenium oxide nanoparticles (RuO2 NPs, 3-4 nm). The leftover Citrus limetta pulp is chosen as waste biomass since it has N and O based chemical species. Structural, morphological and compositional analysis of PCB and RuO2@PCB revealed well-dispersed RuO2 NPs over the PCB surface. High loading (5.27 at%) of Ru content is achieved due to the large surface area of PCB. Cyclic voltammetry, chronoamperometry and differential pulse voltammetry results suggest that the RuO2@PCB/ITO electrode is capable of detecting hexestrol concentration (in the range of 1 × 10-7-2 × 10-5 M). The practical application of hexestrol detection in milk samples demonstrates the recovery from 96.28 to 101%.

NiO nanocomposites/rGO as a heterogeneous catalyst for imidazole scaffolds with applications in inhibiting the DNA binding activity.

Herein, we report a facile approach to synthesize a new highly versatile heterogeneous catalyst by spontaneous aerial oxidation based on nickel oxide nanocomposites immobilized on surface-functionalized reduced graphene oxide sheets. NiO nanocomposite/reduced graphene oxide (rGO-NiO-NC) is a highly efficient, cost-effective, reusable, selective, and eco-friendly nano-catalyst that does not lose any activity even after five reaction cycles. Nickel loading on the rGO-NiO nanocomposite was found to be 3.3 at%, which contributes to the effective and efficient use of rGO-NiO-NCs as a nano-catalyst for the synthesis of imidazole derivatives. Consequently, a series of imidazole derivatives were synthesized, catalyzed by rGO-NiO-NCs, in 60 min with high yields (86% to 96%) under green conditions. Furthermore, the present synthetic methodology was used for the synthesis of highly aromatic imidazole derivatives (B1-B3) whose calf thymus-DNA binding affinities suggest their superior inhibition ability to displace ethidium bromide (EB), which was further confirmed by molecular docking studies. Additionally, the green chemistry matrix of the synthesis reaction was found to be very close to ideal values, such as carbon efficiency (82.32%), E-factor (0.51), atom economy (77.86%), process mass intensity (1.51), and reaction mass efficiency (66.14%).

A reversible chromogenic covalent organic polymer for gas sensing applications.

A triazine-cored covalent organic polymer (COP) was designed and synthesized via amine linkages under ambient conditions. The novel architecture of the COP was fully characterized via spectroscopic and analytical techniques. The present COP demonstrates a quick, portable and reversible chromogenic response towards noxious HCl vapours.

In-depth understanding of a nano-bio interface between lysozyme and Au NP-immobilized N-doped reduced graphene oxide 2-D scaffolds.

In the present work, nitrogen-doped reduced graphene oxide (NrGO) was synthesized via a hydrothermal treatment of graphene oxide (GO) in the presence of urea. Gold nanoparticles (Au(0) NPs) were immobilized over the surface of NrGO (Au(0)-NrGO). Characterization of the Au(0)-NrGO nanocomposite via FT-IR spectroscopy, Raman spectroscopy, elemental mapping and XPS revealed the doping of N atoms during the reduction of GO. XRD and XPS studies confirmed the presence of Au(0) NPs and EDS analysis showed a 4.51 wt% loading of Au NPs in the Au(0)-NrGO nanocomposite. The morphology of Au(0)-NrGO was explored by SEM and TEM, which showed the presence of spherical Au metal NPs uniformly immobilized on the surface of NrGO. Further, studies on lysozyme (Lys) in the presence of Au(0)-NrGO by UV-visible, fluorescence, and circular dichroism spectroscopy revealed a conformational change in Lys and electrostatic interaction between Lys and Au(0)-NrGO. The DLS result showed an enhancement in the size of the Au(0)-NrGO and Lys conjugates. The Au(0)-NrGO-induced conformational changes in the structure of Lys resulted in a significant decrease in its activity at a certain concentration of Au(0)-NrGO. Moreover, the results showed that Lys favorably binds with the surface of Au(0)-NrGO, resulting in the formation of 2-D scaffolds possibly due to electrostatic and hydrophobic interactions, H-bonding, and interactions between the AuNPs and sulfur-containing amino acid residues of Lys. SEM exhibited the formation of conjugates in the form of 2-D scaffolds due to the biomolecular interactions between Lys and Au(0)-NrGO. The TEM studies revealed that Lys agglomerated around the Au(0) NPs immobilized on the surface of NrGO, which suggests the formation of a protein corona (PC) around the AuNPs. Furthermore, the favorable Au(0) NP-sulphur (PC) interaction was confirmed by the disappearance of the S-S stretching band in the Raman spectra. Overall, the results obtained provide insight into the nano-bio interface and formation of Au(0) NP-PC, which can be used for bioinspired applications, such as biosensing and imaging and the development of advanced functional Au NPs.

Sustainable Solvothermal Conversion of Waste Biomass to Functional Carbon Material: Extending Its Utility as a Biocompatible Cosolvent for Lysozyme.

Functional carbon material synthesis from waste biomass by a sustainable method is of prime importance and has wide variety of applications. Herein, functional carbon materials with structural variability are synthesized using a well-known solvothermal method. The leftover pulp waste biomass (PB) of citrus limetta is converted to functional carbon by treatment with a mixture of choline bitartrate (ChBt) and FeCl3 (1:2 mol ratio) as a solvent. The biomass to solvent ratio is varied as 1:1, 0.8:1, and 0.4:1 during solvothermal treatment to obtain PB-1, PB-2, and PB-3 as functional carbon materials, respectively. On characterization, PB carbon materials were found to be rich in oxygen-containing functional groups possessing different morphologies. Furthermore, results suggested the role of solvent as a soft template and catalyst during the synthesis of carbon materials. The feasibility of synthesized carbon materials as a biocompatible cosolvent for lysozyme was evaluated. In the case of PB-2 material (synthesized using 0.8:1 biomass to solvent ratio), results show an enhancement of lysozyme activity by 150%. Besides, spectroscopic and calorimetric data confirm the preservation of thermal and structural stability of lysozyme in the PB-2 solution. Thus, this study stipulates PB-2 as an excellent cosolvent for protein studies. With this work, we aim to delve into an entirely new arena of applications of biomass in the field of biotechnology.

Structure, DNA/proteins binding, docking and cytotoxicity studies of copper(II) complexes with the first quinolone drug nalidixic acid and 2,2'­dipyridylamine.

This work presents the synthesis, structural characterization and biological affinity of the newly synthesized copper(II) complexes with the first antibacterial quinolone drug nalidixic acid (nal) or N-donor ligand 2,2'­dipyridylamine (bipyam). [Cu(II)(nal)(bipyam)Cl], (2) reveals a distorted square pyramidal based geometry in Cu(II) atom confirmed by X-ray crystallography technique. The theoretical stabilities and optimized structures of the complex were obtained from DFT calculations. The ability of the complexes to bind with calf thymus DNA (CT DNA) were investigated by electronic absorption, fluorescence, circular dichroism, and viscosity measurements techniques. The experimental results reveal that the complexes strongly interact with CT DNA via intercalative mode but complex 2 exhibits the highest affinity giving Kb=3.91±0.13×106, M-1. The fluorescence spectroscopy measurements show that both complexes have the superior ability to the replacement of EtBr from DNA-bound EtBr solution and bind to DNA through intercalative mode. Both complex also shows the superior affinity towards proteins with comparatively high binding constant values which have been further revealed by fluorescence spectroscopy measurements. Molecular docking analysis indicates that the interaction of the complexes and proteins are stabilized by hydrogen bonding and hydrophobic interaction. Furthermore, the results of in vitro cytotoxicity reveal that the complex 2 has excellent cytotoxicity than 1 against human breast cancer cell lines (MCF-7).

Experimental and theoretical investigation of intramolecular cooperativity in cyclic benzene trimer motif.

A series of new symmetrical tripodal molecules 1a-4b with a central benzene scaffold substituted with methyl/ethyl groups and three benzimidazolyl units having a bithiophene/biphenyl/5-alkylthiophene motif at the 2-position via a -CH2- unit were synthesized and characterized by elemental analysis, HR-MS, and NMR spectroscopy. NMR spectral data reveal that all molecules adopt a cyclic benzene trimer (CBT) using three benzimidazolyl units. Intramolecular cooperative edge-to-face C-H⋯π interactions stabilize the CBT motif in solution and are strong in ethyl substituted molecules (1b-4b) compared to methyl substituted (1a-4a) ones. However, the strength of the CBT unit in the tripodal molecule is independent of the length of the substituent at the 2-position of the benzimidazolyl unit. The relative 1H NMR chemical shift calculated at the MPW1PW91/6-311+G(d,p) level of theory corroborates the experimental values, and the calculations predict the distribution of the structures into syn isomers. The relative change in the NMR chemical shift is justified by the relative change in the magnitude of the (3,+3) critical point (CP) in the molecular electrostatic potential (MESP) topography. Also, a linear correlation of the intramolecular C-H⋯π interactions evaluated at M062X/6-311+G(d,p) with the relative NMR chemical shift suggest the latter as a measure of intramolecular cooperativity.

Reduced graphene oxide nanoribbon immobilized gold nanoparticle based electrochemical DNA biosensor for the detection of Mycobacterium tuberculosis.

Tuberculosis is one of the most dreadful diseases caused by Mycobacterium tuberculosis with more than 9 million individuals suffering from it in 2014. Traditional methods of detection are not efficient enough for its quick and reliable detection; therefore, it is imperative to develop methods of its detection in the early stages. Consequently, we report a highly sensitive and selective biosensor for detection of Mycobacterium tuberculosis. In this work, gold nanoparticles (AuNPs, dia. ∼6 nm, 1.81 wt% loading) are immobilized over reduced graphene oxide nanoribbons (RGONRs). An ssDNA/Au/RGONR electrode is prepared by immobilizing Au nanoparticles followed by covalent modification of Au nanoparticles with 5'SH-ssDNA. As per the best knowledge of the authors, the target DNA of Mycobacterium tuberculosis is detected using a ssDNA/Au/RGONR bioelectrode by cyclic voltammetry and chronoamperometric methods for the first time. With high detection efficiency (0.1 fM), the ssDNA/Au/RGONR bioelectrode exhibited better signal amplification and electrochemical response as compared to bare Au and RGONR electrodes. Additionally, the ssDNA/Au/RGONR bioelectrode displayed good linear response to different concentrations of target M. tuberculosis DNA. The ssDNA/Au/RGONR has shown excellent specificity (92%) to Mycobacterium tuberculosis target DNA as compared with non-complementary DNA. The Au/RGONR matrix has the potential to be used as an immobilization platform for single-stranded probe DNAs of different diseases other than tuberculosis reported here.

Fur-Imine-Functionalized Graphene Oxide-Immobilized Copper Oxide Nanoparticle Catalyst for the Synthesis of Xanthene Derivatives.

Fur-imine-functionalized graphene oxide-immobilized copper oxide nanoparticles (Cu(II)-Fur-APTES/GO) are synthesized and found to be a cost-effective, efficient, and reusable heterogeneous nanocatalyst for the preparation of pharmaceutically important xanthene derivatives under greener solvent conditions. Cu(II)-Fur-APTES/GO exhibits excellent result in the synthesis of xanthenes with reduced reaction time (25-50 min) and higher yields (up to 95%) and has a simple procedure, ease of product separation, and no byproducts. Moreover, the nanocatalyst has a Cu loading of 13.5 at. % over functionalized GO which is far superior than the already known metal-based heterogeneous catalysts. The newly synthesized catalyst has been characterized by various physiochemical techniques such as X-ray photoelectron spectroscopy, X-ray diffraction, energy-dispersive X-ray, Raman spectroscopy for structural characterization, field emission scanning electron microscopy and high-resolution transmission electron microscopy for morphological characterization. The catalyst showed admirable recyclability up to five consecutive runs, and there was no appreciable loss in catalytic efficiency.

La2O3/Reduced Graphene Oxide Nanocomposite: A Highly Efficient, Reusable Heterogeneous Catalyst for the Synthesis of Biologically Important Bis(indolyl)methanes Under Solvent Free Conditions.

Synthesis and characterization of Lanthanum Oxide-reduced graphene oxide (La2O3/RGO) nanocomposite and its application as heterogeneous, reusable catalyst has been reported in this article. Biologically important molecules bis(indolyl)methanes are synthesized in mild reaction condition with excellent yield under solvent free condition. Catalyst was reused for four times without any significant changes in the yields obtained. Reusability, green synthesis and environmentally benign nature makes La2O3/RGO one of the best catalyst for the synthesis of biologically important bis(indolyl)methanes.

Metal complex of the first-generation quinolone antimicrobial drug nalidixic acid: structure and its biological evaluation.

A novel binuclear squire planar complex of nalidixic acid with Ag(I) metal ion with the formula [Ag(Nal)2] has been synthesized. The synthesized metal complex was characterized using CHN analysis, Fourier-transformed infra-red (FT-IR), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), ultra violet-visible (Uv-vis) and single-crystal X-ray diffraction (XRD). The newly synthesized complex shows more advanced antifungal activity compared to the parent quinolone against four fungi, namely Pythium aphanidermatum, Sclerotinia rolfsii, Rhizoctonia solani and Rhizoctonia bataticola.