Phytosynthesis and characterization of TiO2 nanoparticles using diospyros ebenum leaf extract and their antibacterial and photocatalytic degradation of crystal violet

Crystalline anatase titanium dioxide (TiO2) nanoparticles (NPs) were prepared by eco friendly, facile and green synthesis of Diospyros ebenum leaf extract as reducing agent and were reported for the first time. The crystallization nature, morphology of the particles, and stability of the nanoparticles were investigated at different calcinations temperatures. The synthesized TiO2 NPs were investigated for the performance of photodegradation of crystal violet (CV) dye under UV light irradiation. Effects of temperatures on structural properties, photocatalytic activity, and the antibacterial activity of TiO2 NP were evaluated. This study revealed that TiO2 NP synthesized at 600 °C exhibited high photocatalytic efficiency and dye adsorption capacity when compared to other synthesized TiO2 NP and exhibited excellent antibacterial activity

Solution Processed NiO/MoS₂ Heterostructure Nanocomposite for Supercapacitor Electrode Application

Metal oxide and metal dichalcogenide heterostructure composites are promising candidates for electrochemical use. In this study, a hybrid heterostructure composite electrode material was made using a straightforward hydrothermal process using transition metal oxide (NiO) and metal dichalcogenide (MoS2). The surface of the flower-like structured MoS2 was grown with granular structured NiO, and this heterostructure composite exhibited considerably improved specific capacitance when compared to the pure NiO and MoS2 materials. The pseudocapacitive performance was effectively supported by the heterostructure combination of transition metal oxide (TMOs) and metal dichalcogenide (MDC), which greatly improved ion transport within the material and storage. At a current density of 1 A/g, the prepared heterostructure composite electrode material exhibited a specific capacitance of 289 F/g, and, after 2000 cycles, the capacitance retained 101% of its initial value. The symmetric device was constructed and put through tests using LED light. This finding opens up a new avenue for the quickly increasing the field of heterostructure materials

Synthesis of Bimetallic BiPO4/ZnO Nanocomposite: Enhanced Photocatalytic Dye Degradation and Antibacterial Applications

Multidrug-resistant strains (MDRs) are becoming a major concern in a variety of settings, including water treatment and the medical industry. Well-dispersed catalysts such as BiPO4, ZnO nanoparticles (NPs), and different ratios of BiPO4/ZnO nanocomposites (NCs) were synthesized through hydrothermal treatments. The morphological behavior of the prepared catalysts was characterized using XRD, Raman spectra, PL, UV–Vis diffuse reflectance spectroscopy (UV-DRS), SEM, EDX, and Fe-SEM. MDRs were isolated and identified by the 16s rDNA technique as belonging to B. flexus, B. filamentosus, P. stutzeri, and A. baumannii. The antibacterial activity against MDRs and the photocatalytic methylene blue (MB) dye degradation activity of the synthesized NPs and NCs were studied. The results demonstrate that the prepared BiPO4/ZnO-NCs (B1Z4-75:300; NCs-4) caused a maximum growth inhibition of 20 mm against A. baumannii and a minimum growth inhibition of 12 mm against B. filamentosus at 80 μg mL−1 concentrations of the NPs and NCs. Thus, NCs-4 might be a suitable alternative to further explore and develop as an antibacterial agent. The obtained results statistically justified the data (p ≤ 0.05) via one-way analysis of variance (ANOVA). According to the results of the antibacterial and photocatalytic study, we selected the best bimetallic NCs-4 for the photoexcited antibacterial effect of MDRs, including Gram ve+ and Gram ve− strains, via UV light irradiation. The flower-like NCs-4 composites showed more effectiveness than those of BiPO4, ZnO, and other ratios of NCs. The results encourage the development of flower-like NCs-4 to enhance the photocatalytic antibacterial technique for water purification

Synthesis of Bimetallic BiPO₄/ZnO Nanocomposite: Enhanced Photocatalytic Dye Degradation and Antibacterial Applications

Multidrug-resistant strains (MDRs) are becoming a major concern in a variety of settings, including water treatment and the medical industry. Well-dispersed catalysts such as BiPO4, ZnO nanoparticles (NPs), and different ratios of BiPO4/ZnO nanocomposites (NCs) were synthesized through hydrothermal treatments. The morphological behavior of the prepared catalysts was characterized using XRD, Raman spectra, PL, UV–Vis diffuse reflectance spectroscopy (UV-DRS), SEM, EDX, and Fe-SEM. MDRs were isolated and identified by the 16s rDNA technique as belonging to B. flexus, B. filamentosus, P. stutzeri, and A. baumannii. The antibacterial activity against MDRs and the photocatalytic methylene blue (MB) dye degradation activity of the synthesized NPs and NCs were studied. The results demonstrate that the prepared BiPO4/ZnO-NCs (B1Z4-75:300; NCs-4) caused a maximum growth inhibition of 20 mm against A. baumannii and a minimum growth inhibition of 12 mm against B. filamentosus at 80 μg mL−1 concentrations of the NPs and NCs. Thus, NCs-4 might be a suitable alternative to further explore and develop as an antibacterial agent. The obtained results statistically justified the data (p ≤ 0.05) via one-way analysis of variance (ANOVA). According to the results of the antibacterial and photocatalytic study, we selected the best bimetallic NCs-4 for the photoexcited antibacterial effect of MDRs, including Gram ve+ and Gram ve− strains, via UV light irradiation. The flower-like NCs-4 composites showed more effectiveness than those of BiPO4, ZnO, and other ratios of NCs. The results encourage the development of flower-like NCs-4 to enhance the photocatalytic antibacterial technique for water purification

A Bacteriophage T4 Nanoparticle-Based Dual Vaccine against Anthrax and Plague

Following the deadly anthrax attacks of 2001, the Centers for Disease Control and Prevention (CDC) determined that Bacillus anthracis and Yersinia pestis that cause anthrax and plague, respectively, are two Tier 1 select agents that pose the greatest threat to the national security of the United States. Both cause rapid death, in 3 to 6 days, of exposed individuals. We engineered a virus nanoparticle vaccine using bacteriophage T4 by incorporating key antigens of both B. anthracis and Y. pestis into one formulation. Two doses of this vaccine provided complete protection against both inhalational anthrax and pneumonic plague in animal models. This dual anthrax-plague vaccine is a strong candidate for stockpiling against a potential bioterror attack involving either one or both of these biothreat agents. Further, our results establish the T4 nanoparticle as a novel platform to develop multivalent vaccines against pathogens of high public health significance.Bacillus anthracis and Yersinia pestis, the causative agents of anthrax and plague, respectively, are two of the deadliest pathogenic bacteria that have been used as biological warfare agents. Although Biothrax is a licensed vaccine against anthrax, no Food and Drug Administration-approved vaccine exists for plague. Here, we report the development of a dual anthrax-plague nanoparticle vaccine employing bacteriophage (phage) T4 as a platform. Using an in vitro assembly system, the 120- by 86-nm heads (capsids) of phage T4 were arrayed with anthrax and plague antigens fused to the small outer capsid protein Soc (9 kDa). The antigens included the anthrax protective antigen (PA) (83 kDa) and the mutated (mut) capsular antigen F1 and the low-calcium-response V antigen of the type 3 secretion system from Y. pestis (F1mutV) (56 kDa). These viral nanoparticles elicited robust anthrax- and plague-specific immune responses and provided complete protection against inhalational anthrax and/or pneumonic plague in three animal challenge models, namely, mice, rats, and rabbits. Protection was demonstrated even when the animals were simultaneously challenged with lethal doses of both anthrax lethal toxin and Y. pestis CO92 bacteria. Unlike the traditional subunit vaccines, the phage T4 vaccine uses a highly stable nanoparticle scaffold, provides multivalency, requires no adjuvant, and elicits broad T-helper 1 and 2 immune responses that are essential for complete clearance of bacteria during infection. Therefore, phage T4 is a unique nanoparticle platform to formulate multivalent vaccines against high-risk pathogens for national preparedness against potential bioterror attacks and emerging infections

Mutated and Bacteriophage T4 Nanoparticle Arrayed F1-V Immunogens from <i>Yersinia pestis</i> as Next Generation Plague Vaccines

<div><p>Pneumonic plague is a highly virulent infectious disease with 100% mortality rate, and its causative organism <i>Yersinia pestis</i> poses a serious threat for deliberate use as a bioterror agent. Currently, there is no FDA approved vaccine against plague. The polymeric bacterial capsular protein F1, a key component of the currently tested bivalent subunit vaccine consisting, in addition, of low calcium response V antigen, has high propensity to aggregate, thus affecting its purification and vaccine efficacy. We used two basic approaches, structure-based immunogen design and phage T4 nanoparticle delivery, to construct new plague vaccines that provided complete protection against pneumonic plague. The NH₂-terminal β-strand of F1 was transplanted to the COOH-terminus and the sequence flanking the β-strand was duplicated to eliminate polymerization but to retain the T cell epitopes. The mutated F1 was fused to the V antigen, a key virulence factor that forms the tip of the type three secretion system (T3SS). The F1mut-V protein showed a dramatic switch in solubility, producing a completely soluble monomer. The F1mut-V was then arrayed on phage T4 nanoparticle via the small outer capsid protein, Soc. The F1mut-V monomer was robustly immunogenic and the T4-decorated F1mut-V without any adjuvant induced balanced T_H1 and T_H2 responses in mice. Inclusion of an oligomerization-deficient YscF, another component of the T3SS, showed a slight enhancement in the potency of F1-V vaccine, while deletion of the putative immunomodulatory sequence of the V antigen did not improve the vaccine efficacy. Both the soluble (purified F1mut-V mixed with alhydrogel) and T4 decorated F1mut-V (no adjuvant) provided 100% protection to mice and rats against pneumonic plague evoked by high doses of <i>Y. pestis</i> CO92. These novel platforms might lead to efficacious and easily manufacturable next generation plague vaccines.</p></div

Designing monomeric F1 mutants.

<p>(<b>A</b>) Schematic of native F1, F1mut1, and F1mut2 recombinant constructs. The donor β-strand of F1 is shown in pink, the T cell epitope region in blue, and the rest of the F1 coding sequence in green. The numbers correspond to the aa residues of F1. Native F1 has one hexa-histidine tag (orange) at the NH₂-terminus, whereas F1mut1 and F1mut2 have two hexa-histidine tags, one at the NH₂-terminus and another at the COOH-terminus. (<b>B</b>) Expression and solubility analysis. The recombinant F1 proteins were over-expressed by adding IPTG to 1 mM final concentration. The samples at 0, 1, or 2 h time points were analyzed by SDS-PAGE (15% gel) and Coomassie blue staining. The positions of F1 protein bands are marked with red arrows. The samples at 1 h or 2 h time points were analyzed for solubility using the B-PER reagent. S, soluble fraction (supernatant from 12,000 <i>g</i> centrifugation of the lysate); P, insoluble fraction (pellet); M, molecular weight standards. (<b>C</b>) Purification of F1mut1. The F1mut1 recombinant protein was purified from the cell-free lysates by HisTrap affinity chromatography followed by Hi-load 16/60 Superdex 200 gel filtration. The molecular weight of F1mut1 peak fraction was calculated from the calibration curve constructed by gel filtration on the same column of standard proteins of known molecular weight [Thyroglobulin (669 kDa), Ferritin (440 kDa), Catalase (232 kDa), aldolase (158 kDa), Ovalbumin (43 kDa), RNase A (14 kDa), and Albumin (67 kDa)]. The insert shows the purity of F1mut1 protein after SDS-PAGE and Coomassie blue staining of the peak fraction. Similar results were obtained with the F1mut2 recombinant protein. See <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003495#s4" target="_blank">Materials and Methods</a> for additional details.</p

An oligomerization deficient YscF mutant.

<p>(<b>A</b>) Schematic of native YscF and YscF35/67 mutants. (<b>B</b>) Purification of YscF and YscF35/67 mutant proteins. The gel filtration profiles showed that the native YscF eluted as a broad peak spanning the entire high molecular weight range and the mutated YscF35/67 eluted as two peaks, one as a high molecular weight aggregate near the void volume, and another at 22 kDa corresponding to the size of a dimer. (<b>C</b>) Purity of YscF and YscF35/67 proteins as analyzed by SDS-PAGE and Coomassie blue staining of the peak fractions.</p