Construction of a Copper Bismuthate/Graphene Nanocomposite for Electrochemical Detection of Catechol.

Binary metal oxides with carbon nanocomposites have received extensive attention as research hotspots in the electrochemistry field owing to their tunable properties and superior stability. This work illustrates the development of a facile sonochemical strategy for the synthesis of a copper bismuthate/graphene (GR) nanocomposite-modified screen-printed carbon electrode (CBO/GR/SPCE) for the electrochemical detection of catechol (CT). The formation of an as-prepared CBO/GR nanocomposite was comprehensively characterized. The electrochemical behavior of the CBO/GR/SPCE toward CT was investigated by voltammetry and amperometry techniques. The fabricated CBO/GR/SPCE manifests an excellent electrocatalytic performance toward CT with a lower peak potential and a higher current value compared to those of CBO/SPCE, GR/SPCE, and bare SPCE. It is attributed to enhanced electro-catalytic activity, synergetic effects, and good active sites of the CBO/GR nanocomposite. Under the electrochemical condition, the CBO/GR/SPCE displayed a wide linear sensing range, trace-level detection limit, acceptable sensitivity, and excellent selectivity. Furthermore, our proposed CBO/GR electrode was employed successfully for CT detection in water samples.

Chitosan overlaid Fe3O4/rGO nanocomposite for targeted drug delivery, imaging, and biomedical applications.

A hybrid and straightforward nanosystem that can be used simultaneously for cancer-targeted fluorescence imaging and targeted drug delivery in vitro was reported in this study. A chitosan (CS) polymer coated with reduced graphene oxide (rGO) and implanted with Fe3O4 nanoparticles was fabricated. The fundamental physicochemical properties were confirmed via FT-IR, XRD, FE-SEM, HR-TEM, XPS, and VSM analysis. The in vivo toxicity study in zebrafish showed that the nanocomposite was not toxic. The in vitro drug loading amount was 0.448 mg/mL-1 for doxorubicin, an anticancer therapeutic, in the rGO/Fe3O4/CS nanocomposite. Furthermore, the pH-regulated release was observed using folic acid. Cellular uptake and multimodal imaging revealed the benefit of the folic acid-conjugated nanocomposite as a drug carrier, which remarkably improves the doxorubicin accumulation inside the cancer cells over-express folate receptors. The rGO/Fe3O4/CS nanocomposite showed enhanced antibiofilm and antioxidant properties compared to other materials. This study's outcomes support the use of the nanocomposite in targeted chemotherapy and the potential applications in the polymer, cosmetic, biomedical, and food industries.

Biocompatible properties of nano-drug carriers using TiO2-Au embedded on multiwall carbon nanotubes for targeted drug delivery.

Nanomaterial-based drug carriers have become a hot spot of research at the interface of nanotechnology and biomedicine because they allow efficient loading, targeted delivery, controlled release of drugs, and therefore are promising for biomedical applications. The current study made an attempt to decorate the multiwalled carbon nanotubes (MWCNT) with titanium dioxide­gold nanoparticles in order to enhance the biocompatibility for doxorubicin (DOX) delivery. The successful synthesis of nano drug carrier (NDC) was confirmed by XRD, XPS and UV-Visible spectroscopy. FESEM and TEM revealed that the morphology of NDC can be controlled by manipulating the reaction duration, MWCNT concentration and TiO2-Au source concentration. Results showed that TiO2 and Au nanoparticles were well coated on MWCNT. NDC had finely tuned biocompatible properties, as elucidated by hemolytic and antimicrobial assays. NDC also showed a high antioxidant potential, 80.7% expressed as ascorbic acid equivalents. Commercial DOX drug was utilized to treat A549 and MCF7 cancer cell lines showing improved efficiency by formulating it with NDC, which selectively delivered at the pH 5.5 with drug loading capacity of 0.45 mg/mL. The drug releasing capacity achieved by NDC was 90.66% for 10 h, a performance that far encompasses a wide number of current literature reports.

Green synthesis of gold nanoparticles using a cheap Sphaeranthus indicus extract: Impact on plant cells and the aquatic crustacean Artemia nauplii.

The impact of green-fabricated gold nanoparticles on plant cells and non-target aquatic species is scarcely studied. In this research, we reported an environment friendly technique for the synthesis of gold nanoparticles (Au NPs) using the Sphaeranthus indicus leaf extract. The formation of the metal NPs was characterized by UV-Visible and FT-IR spectroscopy, XRD, SEM and TEM analyses. The UV-Visible spectra of Au NPs showed a surface plasmon resonance peak at 531nm. FT-IR analysis indicated functional bio-molecules associated with Au NPs formation. The crystalline nature of Au nanoparticles was confirmed by their XRD diffraction pattern. TEM revealed the spherical shape with a mean particle size of 25nm. Au NPs was tested at 0, 1, 3, 5, 7 and 10% doses in mitotic cell division assays, pollen germination experiments, and in vivo toxicity trials against the aquatic crustacean Artemia nauplii. Au NPs did not show any toxic effects on plant cells and aquatic invertebrates. Notably, Au NPs promoted mitotic cell division in Allium cepa root tip cells and germination of Gloriosa superba pollen grains. Au NPs showed no mortality on A. nauplii, all the tested animals showed 100% survivability. Therefore, these Au NPs have potential applications in the development of pollen germination media and plant tissue culture.

Synthesis and characterization of MWCNT/TiO2/Au nanocomposite for photocatalytic and antimicrobial activity.

A novel combination of titanium oxide (TiO2)/gold (Au)/multiwalled carbon nanotubes (MWCNTs) nanocomposite (NC) was synthesised by sol- gel method. MWCNT functionalisation by modified Hummers method. TiO2/Au nanoparticles (NPs) were synthesised by biological method using Terminalia chebula bark extract. MWCNT/TiO2/Au NC samples were characterised by X-ray diffraction, ultraviolet-visible-diffuse reflectance spectra, microRaman, scanning electron microscopy and high-resolution-transmission electron microscopy analyses. The photocatalytic performance of the obtained for NC toward the decomposition of congo-red and the antimicrobial activity for inhibition of Gram positive (Bacillus subtilis, Streptococcus pneumonia and Staphylococcus aureus), Gram negative (Shigella dysenderiae, Proteus vulgaris and Klebsiella pneumonia) and fungal strains have been evaluated and the results are compared with positive control ampicillin. The metal and metal-oxide NPs have a lower sorption capacity. The herbicidal bond to the tested CNTs by the combination of electron donor-acceptor interactions and hydrogen bonds. In particular, the dispersion of NC and control of sodium borohydride, it has more efficient effect on the photodegradation and antibacterial activity of positive control of ampicillin. The NC material has exhibited maximum photodegradation and antibacterial activity results of zone of inhibition when compared with control samples.

Guazuma ulmifolia bark-synthesized Ag, Au and Ag/Au alloy nanoparticles: Photocatalytic potential, DNA/protein interactions, anticancer activity and toxicity against 14 species of microbial pathogens.

In the present study, we focused on a quick and green method to fabricate Ag, Au and Ag/Au alloy nanoparticles (NPs) using the bark extract of Guazuma ulmifolia L. Green synthesized metal NPs were characterized using different techniques, including UV-Vis spectroscopy, FT-IR, XRD, AFM and HR-TEM analyses. The production of Ag, Au and Ag/Au alloy NPs was observed monitoring color change from colorless to brown, followed by pink and dark brown, as confirmed by UV-Vis spectroscopy characteristic peaks at 436, 522 and 510nm, respectively. TEM shed light on the spherical shapes of NPs with size ranges of 10-15, 20-25 and 10-20nm. Biosynthesized NPs showed good catalytic activity reducing two organic dyes, 4-nitrophenol (4-NP) and Congo red (CR). UV-vis spectroscopy, fluorescence, circular dichroism spectroscopy and viscosity analyses were used to investigate the NP binding with calf thymus DNA. The binding constant of NPs with DNA calculated in UV-Vis absorption studies were 1.18×104, 1.83×104 and 2.91×104M-1, respectively, indicating that NPs were able to bind DNA with variable binding affinity: Ag/Au alloy NPs>Ag NPs>Au NPs. Ag/Au alloy NPs also showed binding activity to bovine serum albumin (BSA) over the other NPs. Ag and Ag/Au alloy NPs exhibited good antimicrobial activity on 14 species of microbial pathogens. In addition, the cytotoxic effects of Ag/Au alloy NPs were studied on human cervical cancer cells (HeLa) using MTT assay. Overall, our work showed the promising potential of bark-synthesized Ag and Ag/Au alloy NPs as cheap sources to develop novel and safer photocatalytic, antimicrobial and anticancer agents.

Green synthesis of silver, gold and silver/gold bimetallic nanoparticles using the Gloriosa superba leaf extract and their antibacterial and antibiofilm activities.

The green fabrication of metal nanoparticles using botanical extracts is gaining increasing research attention in nanotechnology, since it does not require high energy inputs or the production of highly toxic chemical byproducts. Here, silver (Ag), gold (Au) and their bimetallic (Ag/Au) nanoparticles (NPs) were green synthesized using the Gloriosa superba aqueous leaf extract. Metal NPs were studied by spectroscopic (UV-visible spectroscopy, fluorescence spectroscopy, FT-IR spectroscopy, XRD and EDX) and microscopic (AFM and TEM) analysis. AFM and TEM showed that Ag and Au NPs had triangular and spherical morphologies, with an average size of 20 nm. Bimetallic Ag/Au NPs showed spherical shapes with an average size of 10 nm. Ag and Ag/Au bimetallic NPs showed high antibacterial and antibiofilm activities towards Gram-positive and Gram-negative bacteria. Overall, the proposed synthesis route of Ag, Au and Ag/Au bimetallic NPs can be exploited by the pharmaceutical industry to develop drugs effective in the fight against microbic infections.

Synthesis of cerium oxide nanoparticles using Gloriosa superba L. leaf extract and their structural, optical and antibacterial properties.

CeO2 nanoparticles (NPs) were green synthesized using Gloriosa superba L. leaf extract. The synthesized nanoparticles retained the cubic structure, which was confirmed by X-ray diffraction studies. The oxidation states of the elements (C (1s), O (1s) and Ce (3d)) were confirmed by XPS studies. TEM images showed that the NPs possessed spherical shape and particle size of 5nm. The Ce-O stretching bands were observed at 451cm(-1) and 457cm(-1) from the FT-IR and Raman spectra respectively. The band gap of the CeO2 NPs was estimated as 3.78eV from the UV-visible spectrum. From the photoluminescence measurements, the broad emission composed of eight different bands were found. The antibacterial studies performed against a set of bacterial strains showed that Gram positive (G+) bacteria were relatively more susceptible to the NPs than Gram negative (G-) bacteria. The toxicological behavior of CeO2 NPs was found due to the synthesized NPs with uneven ridges and oxygen defects in CeO2 NPs.