Correction: Platinum nanoparticles inhibit bacteria proliferation and rescue zebrafish from bacterial infection.

[This corrects the article DOI: 10.1039/C6RA03732A.].

Author Correction: Jacalin capped platinum nanoparticles confer persistent immunity against multiple Aeromonas infection in zebrafish.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Jacalin capped platinum nanoparticles confer persistent immunity against multiple Aeromonas infection in zebrafish.

Bacterial resistance is a major clinical problem, which is compounded by both a lack of new antibiotics and emergence of multi- and extremely-drug resistant microbes. In this context, non-toxic nanoparticles could play an important role in conferring protection against bacterial infections and in this study we have made an attempt to show the usefulness of jacalin capped platinum nanoparticles in protecting zebrafish against multiple infections with Aeromonas hydrophila. Our results also indicate that use of nanoparticles promotes adaptive immune response against the pathogen, so much so that zebrafish is able to survive repetitive infection even after twenty one days of being treated with jacalin-capped platinum nanoparticles. This is significant given that platinum salt is not antibacterial and jacalin is non-immunogenic. Our study for the first time reveals a novel mechanism of action of nanoparticles, which could form an alternate antibacterial strategy with minimal bacterial resistance.

C-H oxidation and chelation of a dipyrromethane mediated rapid colorimetric naked-eye Cu(ii) chemosensor.

Copper(ii) ion mediated C-H oxidation of dipyrromethanes (DPMs) to the corresponding dipyrrins followed by complexation invoked the selective sensing of copper(ii) ions in aqueous solutions. On the addition of copper, the colour of the DPM solution instantaneously changes from yellow to pink with the detection limit of 0.104 µM measured by absorption spectroscopy, whereas visible colour changes could be observed by the naked eye for concentrations as low as 3 µM.

Phytoproteins in green leaves as building blocks for photosynthesis of gold nanoparticles: An efficient electrocatalyst towards the oxidation of ascorbic acid and the reduction of hydrogen peroxide.

Herein, we present a simple and green method for the synthesis of gold nanoparticles (AuNPs) using the phytoproteins of spinach leaves. Under ambient sunlight irradiation, the isolated phytoprotein complex from spinach leaves reduces the gold chloride aqueous solution and stabilizes the formed AuNPs. As prepared nanoparticles were characterized by UV-visible spectroscopy, Fourier transform infra-red (FTIR) spectroscopy, zeta potential, transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDS). The surface plasmon resonance (SPR) maximum for AuNPs was observed at 520 nm. The zeta potential value estimated for the AuNPs is -27.0 mV, indicating that the NPs are well separated. Transmission electron micrographs revealed that the particles are spherical in nature with the size range from 10 to 15 nm. AuNPs act as a catalyst in the degradation of an azo dye, methyl orange in an aqueous environment. The reduction rate was determined to be pseudo-first order. Electrocatalytic efficiency of the synthesized AuNPs via this green approach was studied by chronoamperometry using ascorbic acid and hydrogen peroxide as a model compound for oxidation and reduction, respectively. Electrocatalytic studies indicate that the gold nanoparticles can be used to detect ascorbic acid and hydrogen peroxide in micromolar concentrations with response time less than 3s.

Synthesis and characterization of zinc sulfide quantum dots and their interaction with snake gourd (Trichosanthes anguina) seed lectin.

Owing to the use of quantum dots in biological labeling, and the specific interaction of lectins with tumor cells, studies on lectin-QDs interaction are of potential interest. Herein, we report a facile method to prepare zinc sulfide quantum dots (ZnS QDs) using pectin as a capping agent and studied their interaction with snake gourd seed lectin (SGSL) by fluorescence spectroscopy. The QDs were characterized by X-ray diffraction, high-resolution transmission electron microscopy, UV-Vis absorption and fluorescence spectroscopy. The thermodynamic forces governing the interaction between ZnS-QDs and SGSL have been delineated from the temperature dependent association constant. These results suggest that the binding between ZnS QDs and SGSL is governed by enthalpic forces with negative entropic contribution. The red shift of synchronous fluorescence spectra showed that the microenvironment around the tryptophan residues of SGSL was perturbed by ZnS-QDs. The obtained results suggest that the development of optical bioimaging agents by using the conjugated lectin-QDs would be possible to diagnose cancerous tissues.

Interaction of sugar stabilized silver nanoparticles with the T-antigen specific lectin, jacalin from Artocarpus integrifolia.

The advances in nanomedicine demonstrate the anticancer properties of silver nanoparticles (AgNPs) and considered as an alternative to the available chemotherapeutic agents. Owing to the preferential interaction of Artocarpus integrifolia lectin (jacalin) with Galß1-3GalNAcα (a chemically well-defined tumor associated antigen), a study was undertaken to understand the interaction mechanism of AgNPs with jacalin in presence of specific sugar, galactose. Fluorescence spectroscopic analysis revealed that the AgNPs binding significantly quenched the intrinsic fluorescence of jacalin through a static quenching mechanism, and a non-radiative energy transfer occurred within the molecules. Association constants obtained from the interaction of different sugar-stabilized AgNPs with jacalin are in the order of 10(4)M(-1), this is in the same range as those obtained for the interaction of lectin with carbohydrate and hydrophobic ligand. Each subunit of the tetrameric jacalin binds one AgNPs, and the stoichiometry was unaffected by the presence of the specific sugar, galactose. Hemagglutination assay shows that sugar stabilized AgNPs interacts to jacalin at a site that is different from the saccharide-binding site. Analysis of the FTIR spectra of jacalin indicates that the binding of AgNPs does not alter the secondary structure of jacalin. More importantly, AgNPs exists in nano form even after interacting with the lectin. These results suggest that the development of lectin-AgNPs conjugate would be possible for diagnosis and treatment of cancer.

Spectroscopic investigation on the interaction of ruthenium complexes with tumor specific lectin, jacalin.

Several ruthenium complexes are regarded as anticancer agents and considered as an alternative to the widely used platinum complexes. Owing to the preferential interaction of jacalin with tumor-associated T-antigen, we report the interaction of jacalin with four ruthenium complex namely, tris(1,10-phenanthroline)ruthenium(II)chloride, bis(1,10-phenanthroline)(N-[1,10]phenanthrolin-5-yl-pyrenylmethanimine)ruthenium(II)chloride, bis(1,10-phenanthroline)(dipyrido[3,2-a:2',3'-c]-phenazine)ruthenium(II)chloride, bis(1,10-phenanthroline)(11-(9-acridinyl)dipyrido[3,2-a:2',3'-c]phenazine)ruthenium(II) chloride. Fluorescence spectroscopic analysis revealed that the ruthenium complexes strongly quenched the intrinsic fluorescence of jacalin through a static quenching procedure, and a non-radiative energy transfer occurred within the molecules. Association constants obtained for the interaction of different ruthenium complexes with jacalin are in the order of 10(5) M(-1), which is in the same range as those obtained for the interaction of lectin with carbohydrate and hydrophobic ligand. Each subunit of the tetrameric jacalin binds one ruthenium complex, and the stoichiometry is found to be unaffected by the presence of the specific sugar, galactose. In addition, agglutination activity of jacalin is largely unaffected by the presence of the ruthenium complexes, indicating that the binding sites for the carbohydrate and the ruthenium complexes are different. These results suggest that the development of lectin-ruthenium complex conjugate would be feasible to target malignant cells in chemo-therapeutics.

Preparation of gold nanoparticles using Salicornia brachiata plant extract and evaluation of catalytic and antibacterial activity.

The current study deals with the synthesis of gold nanoparticles (AuNPs) using Salicornia brachiata (Sb) and evaluation of their antibacterial and catalytic activity. The SbAuNPs showed purple color with a characteristic surface plasmon resonance peak at 532 nm. Scanning electron microscopy and transmission electron microscopy revealed polydispersed AuNPs with the size range from 22 to 35 nm. Energy dispersive X-ray and thin layer X-ray diffraction analysis clearly shows that SbAuNPs was pure and crystalline in nature. As prepared gold nanoparticles was used as a catalyst for the sodium borohydride reduction of 4-nitro phenol to 4-amino phenol and methylene blue to leucomethylene blue. The green synthesized nanoparticles exhibited potent antibacterial activity against the pathogenic bacteria, as evidenced by their zone of inhibition. In addition, we showed that the SbAuNPs in combination with the regular antibiotic, ofloxacin, exhibit superior antibacterial activity than the individual.