Yasir Anwar

Dye adsorption and bactericidal properties of TiO2/chitosan coating layer.

A new kind of titanium oxide dispersed in chitosan (TiO2/CS) nanocomposite adsorbent was prepared and adhered to high surface area substrate, cellulose microfibers mat (CMM). CS-CMM and TiO2/CS-CMM were used for the thymol violet (TV) dye removal from wastewater. Characterization of materials was carried out by X-ray diffraction, scanning electron microscope and energy dispersive X-ray spectroscopy. The adsorption properties of both the CS-CMM and TiO2/CS-CMM were investigated as a function of adsorbent dosage, solution pH, and contact time. It was revealed that the composites pretreated in the solution with higher pH value exhibited larger adsorption capacities. Kinetic studies showed that the composites could adsorb TV dye rapidly and reached the equilibrium in 90min. The adsorption process followed pseudo-second order kinetics and involved particle diffusion mechanism. The calculated maximum adsorption capacities of CS-CMM and TiO2/CS-CMM were 84.32 and 97.51mgg(-1), respectively. Compare to CS, the TiO2/CS nanocomposite coated CMM showed higher antibacterial characteristics as tested against Escherichia coli.

CuO embedded chitosan spheres as antibacterial adsorbent for dyes.

Chitosan/copper oxide (CS/CuO) composite spheres were prepared by simple mixing of CuO nanomaterials in CS solution followed by dropwise addition to NH4OH solution. The characterizations of all the prepared spheres were carried out by FESEM, EDS, XRD, XPS, and FTIR analyses while the thermal properties were analyzed by TGA. Further the ability of composite spheres was tested as an easily removable pollutant adsorbent from water containing different dyes and compared with pure CS. Composite spheres were found to be the best adsorbent when applied to remove indigo carmine (IC), congo red (CR) and methyl orange (MO) from water. Amongst the three dyes, CS/CuO composite spheres were more selective toward MO adsorption. CS/CuO composite spheres also displayed significant antibacterial activity by inhibiting Pseudomonas aeruginosa growth. Thus the fabricated composite spheres can be used as a biosorbent in the future.

Anti-bacterial chitosan/zinc phthalocyanine fibers supported metallic and bimetallic nanoparticles for the removal of organic pollutants

In this report, we prepared chitosan (CS) membrane, CS/zinc phthalocyanine (ZnPc-CS) composite fibers and pellets as support for the synthesis of zero valent metal nanoparticles. The composite fibers and pellets of ZnPc-CS were prepared by simply dispersing 5wt% of ZnPc in CS solution. ZnPc-CS composite were applied as economical host material for the development of metallic and bimetallic zero valent nanoparticles. The composites of ZnPc-CS were put in 0.1M metals salt solutions (mono- and bi-metallic) for the adsorption of metal ions. The metal ions adsorbed ZnPc-CS fibers were treated with 0.1M sodium borohydride (NaBH4) aqueous solution for conversion of metal ions into nanoparticles. Thus, through water based in-situ preparation process, metals nanoparticles loaded on ZnPc-CS composite fibers and pellets were achieved. The presence of respective metals nanoparticles on the composite fibers was confirmed using FE-SEM, XRD and FTIR. Moreover, we determined that these composites exhibit excellent catalytic efficiency and recyclability in the reduction reactions of 4-nitrophenol (4-NP), methyl orange (MO) and cango red (CR). In addition, these composites displayed high antibacterial activity as tested against pathogenic bacteria Escherichia coli.

Anti-bacterial PES-cellulose composite spheres: dual character toward extraction and catalytic reduction of nitrophenol

Polyethersulfone (PES) based hybrid adsorbents were used for the removal of different phenols from aqueous solutions, which are categorized as major aquatic organic pollutants. In an effort to develop adsorbents with high surface area, PES, PES-silica (PES-SiO2), PES-carbon black (PES-CB) and PES-cellulose acetate-CB (PES-CA-CB) were prepared in the form of spheres and characterized by using FESEM, TEM, EDS, XRD, FTIR, and TGA. All the hybrid spheres were selective toward adsorption of 4-nitrophenol (4-NP) and among different hybrid spheres, PES-CA-CB spheres possessed high affinity and competent selectivity toward 4-NP. Therefore, different adsorption parameters have been optimized for PES-CA-CB spheres. The adsorption uptake of 4-NP onto PES-CA-CB spheres was highly dependent on pH and concentration of 4-NP. The highest adsorption was recognized at a pH around 6. The adsorption isotherm of 4-nitrophenol on PES-CA-CB obeyed the Langmuir model with an adsorption capacity of 128.79 mg g−1. Further, all hybrid spheres were utilized as supporting materials for Cu nanoparticles. Hybrid spheres supported Cu nanoparticles were applied for the catalytic reduction of 4-NP. Among all the hybrid spheres supported Cu nanoparticles, PES-CA-CB spheres supported Cu (Cu@PES-CA-CBspheres) nanoparticles exhibited high catalytic activity. Finally, Cu@PES-CA-CBspheres showed excellent antibacterial activity compared to all the hybrid spheres and hybrid spheres supporting Cu nanoparticles. All these adsorbents and catalysts can be prepared by a very simple method, are easily recovered by just removing the pellet from the solution and can be used several times.

5-Lipoxygenase: A Promising Drug Target Against Inflammatory Diseases-Biochemical and Pharmacological Regulation

5-Lipoxygenase (5-LO) is the key enzyme involved in the synthesis of pro-inflammatory leukotrienes (LTs) and has become a prime target for new drug discovery research and development efforts by the pharmaceutical and biotech industry. The pathophysiological effects of LTs can be modulated by the selective inhibition of 5-LO. In this review, we summarize the established dogma and recent progress on the biochemical and pharmacological regulation of 5-LO and its diverse cellular partners. In the last decade, significant research efforts have led to the exploitation of 5-LO pathway for developing new drugs against inflammatory diseases. Despite few setbacks, a number of promising molecules have moved into clinical development. These fundamental discoveries and proof-of-concept studies will ultimately be helpful in delineating how 5-LO pathway participates in the development of disease phenotype and what are possible key biomarkers of disease progression and regression. Elucidation of molecular mechanism-of-action of 5-LO in individual cell types will pave the way for improving efficacy parameters. Taken together, this combined knowledge about the 5-LO pathway would be helpful in planning collaborative and targeted R&D efforts, by the academic laboratories and pharmaceutical/ biotech industry, for the discovery and development of novel, efficacious and safer drugs against multiple diseases.

Characterization of native fungi responsible for degrading crude oil from the coastal area of Yanbu, Saudi Arabia

ABSTRACT A total of 15 fungal isolates were obtained from oil-contaminated sites near the Red Sea in the Yanbu region. Based on the preliminary DCPIP (2,6-dichlorophenolindophenol) assay, three isolates showed promising oil degrading ability. The next-generation sequencing of the ITS-I and ITS-II internal transcribed spacer regions assigned the isolates to Aspergillus and Penicillium. Among these three strains, Y2 (Aspergillus oryzae) was the most efficient, degrading about 99% of the crude oil. The degradation rates were corroborated using spectrophotometric and gas chromatography–mass spectrometry analyses after two weeks of cultivation in Bushnell–Haas medium. All the three strains proved to be potent oil-degrading strains and, hence, can be utilized to degrade oil contaminants.

Isolation and identification of bacterial consortia responsible for degrading oil spills from the coastal area of Yanbu, Saudi Arabia

ABSTRACT Twenty-three crude-oil-degrading bacteria were isolated from oil-contaminated sites near the Red Sea. Based on a high growth rate on crude oil and on hydrocarbon degradation ability, four strains were selected from the 23 isolated strains for further study. These four strains were selected on the basis of dichlorophenolindophenol assay. The nucleotide sequences of the 16S rRNA gene showed that these isolated strains belonged to genus Pseudomonas and Nitratireductor. Among the four isolates, strains S5 (Pseudomonas sp., 95%) and 4b (Nitratireductor sp., 70%) were the most effective ones in degrading crude oil. Using a spectrophotometer and gas chromatography–mass spectrometry, degradation of more than 90% of the crude oil was observed after two weeks of cultivation in Bushnell–Haas medium. The results showed that these strains have the ability to degrade crude oil and may be used for environmental remediation.

Antiproliferation and antibacterial effect of biosynthesized AgNps from leaves extract of Guiera senegalensis and its catalytic reduction on some persistent organic pollutants

The study concentrate on the biosynthesis of silver nanoparticles (AgNps) from the leaves extract of Guiera senegalensis with focus on its; antiproliferation effect on prostate (PC3), breast (MCF7) and liver (HepG2) cancer cell lines, antibacterial effect on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) and the degradation on 4-nitrophenol (4-NP) and congo red dye (CR). The synthesized AgNps were characterized by FTIR, TEM, FESEM, XRD and EDX analysis. The EDS spectrum revealed that the synthesized nanoparticles (Nps) were composed of 55.45% Ag atoms of spherical shape with approximately 50nm size, identified from TEM and FESEM data. The antiproliferation effect of the AgNps varies with cell lines in a concentration dependent manner. The result showed that the AgNps were more effective on PC3 (IC50 23.48μg/mL) than MCF7 (29.25μg/mL) and HepG2 (33.25μg/mL) by the virtue of their IC50 values. The AgNps were highly effective against E. coli and S. aureus by killing 99% colonies. The AgNps also shows a good catalytic reduction of the toxic organic pollutants in which only 3mg of the AgNps degraded 95% of both CR dye and 4-NP in 22 and 36min respectively. Therefore, the green synthesis of AgNps may have potential applications in pharmacology and industries for the treatment of cancers, bacterial infections and in degrading toxic organic pollutants in water.

Nanocomposites containing polyvinyl alcohol and reinforced carbon-based nanofiller: A super effective biologically active material

A new class of biologically active polymer nanocomposites based on polyvinyl alcohol and reinforced mixed graphene/carbon nanotube as carbon-based nanofillers with a general abbreviation (polyvinyl alcohol/mixed graphene–carbon nanotubes) has been successfully synthesized by an efficient solution mixing method with the help of ultrasonic radiation. Mixed graphene and carbon nanotubes ratio has been prepared (50%:50%) wt by wt. Different loading of mixed graphene–carbon nanotubes (2, 5, 10, 15, and 20 wt%) were added to the host polyvinyl alcohol polymer. In this study, polyvinyl alcohol/mixed graphene–carbon nanotubesa–e nanocomposites were characterized and analyzed by X-ray diffraction, Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, and the thermal stability was measured by thermogravimetric analysis and derivative thermal gravimetric. Fourier transform infrared and X-ray diffraction spectra proved the addition of mixed graphene–carbon nanotubes into polyvinyl alcohol matrix. X-ray diffraction patterns for these nanocomposites showed 2θ = 19.35° and 40° due to the crystal nature of polyvinyl alcohol in addition to 2θ = 26.5° which attributed to the graphite plane of carbon-based nanofillers. Thermal stability of polyvinyl alcohol/mixed graphene–carbon nanotubes nanocomposites was enhanced comparing with pure polyvinyl alcohol. The main degradation step ranged between 360° and 450°C. Moreover, maximum composite degradation temperature has appeared at range from 285°C to 267°C and final composite degradation temperature (FCDT) displayed at a temperature range of 469–491°C. Antibacterial property of polyvinyl alcohol/mixed graphene–carbon nanotubesa–e nanocomposites were tested against Escherichia coli bacteria using the colony forming units technique. Results showed an improvement of antibacterial property. The rate percentages of polyvinyl alcohol/mixed graphene–carbon nanotubesb, polyvinyl alcohol/mixed graphene–carbon nanotubesc, and polyvinyl alcohol/mixed graphene–carbon nanotubesd nanocomposites after 24 h are 6%, 5%, and 7% respectively. However, polyvinyl alcohol/mixed graphene–carbon nanotubese nanocomposite showed hyperactivity, where its reduction percentage remarkably raised up to 100% which is the highest inhibition rate percentage. In addition, polyvinyl alcohol and polyvinyl alcohol/graphene–carbon nanotubesa–d showed colony forming units values/ml 70 × 106 and 65 ± 2 × 106 after 12 h. After 24 h, the colony forming units values/ml were in the range of 86 × 106–95 × 106.

Albizia chevalier based ag nanoparticles: Anti-proliferation, bactericidal and pollutants degradation performance

The eco-friendly biosynthesis of silver nanoparticles (AgNps) from bark extract of Albizia chevalier are reported here for their anti-proliferative, antibacterial and pollutant degradation potentials. The synthesized AgNps were characterized by FTIR spectroscopy, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy dispersive X-rays spectrometry (EDS) and X-ray diffraction studies. The TEM and FESEM images show a monodispersed spherical shaped particles of approximately 30 nm. Crystalline peaks were obtained for the synthesized AgNps in XRD spectrum. The AgNps were investigated for in vitro anticancer and antibacterial activities and its potential to degrade 4-nitrophenol (4-NP) and congo red dye (CR). The MTT results shows a significant dose-dependent antiproliferation effect of the AgNps on the cell lines HepG2, MDA-MB-231 and MFC7. The effect was found more pronounced in MDA-MB-231 as compared to MFC-7 cell lines. The antibacterial results indicated 99 and 95% killing of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) respectively, after 24 h of incubation with the AgNps. The AgNps were found to speed up the reductive degradation of 4-NP and CR dye, which give an alternative route for the removal of toxic organic pollutants from the wastewater. The synthesized AgNps were not only used as a bactericidal and anticancer agent, but also effectively used for the reductive degradation of carcinogenic compounds which are listed as the priority pollutants. Therefore, AgNps have the potential for the treatment of various cancers, bacterial infections and for industrial detoxification of wastewater.