Extracellular Synthesis and Characterization of Silver Nanoparticles-Antibacterial Activity against Multidrug-Resistant Bacterial Strains.

Herein, we report the use of a cell-free extract for the extracellular synthesis of silver nanoparticles (AgNPs) and their potential to address the growing threat of multidrug-resistant (MDR) pathogenic bacteria. The reproducibility of AgNP synthesis was good and AgNP formation kinetics were monitored as a function of various reaction factors via ultraviolet-visible absorption spectroscopy. This green method was dependent on the alkaline pH of the reaction mixture. With the addition of dilute sodium hydroxide, well-dispersed AgNPs could be produced in large quantities via the classical nucleation and growth route. The new biosynthetic route enabled the production of AgNPs within a narrow size range of 4 to 17 nm. The AgNPs were characterized using various techniques and their antibacterial activity against MDR pathogenic bacteria was evaluated. Field-emission scanning electron microscopic imaging revealed prominent morphological changes in Staphylococcus aureus cells due to mechanical damage, which led to cell death. Escherichia coli cells showed signs of contraction and intracellular fluid discharge as a consequence of disrupted cell membrane function. This new biologically-assisted extracellular strategy is potentially useful for the decontamination of surfaces and is expected to contribute to the development of new products containing AgNPs.

Using chemical bath deposition to create nanosheet-like CuO electrodes for supercapacitor applications.

We report the effect of ionic liquids on chemically synthesized hierarchical-like copper oxide (CuO) thin films for supercapacitor applications. Concisely, the CuO thin films were deposited via chemical bath deposition (CBD) using 2-dimethylimidazolium chloride [HPDMIM(C1)], 1-(2',3'-dihydroxypropyl)-3-methylimidazolium chloride [DHPMIM(C1)], and N-(3-methyl-2-oxopropyl)pyridine chloride [MOCPP(C1)] ionic liquid solvents. The effects of the ionic liquid solvents on the morphological evolution of the as-prepared films were analyzed, and electrochemical properties were investigated. The highest specific capacitance was achieved for the electrode with a nanosheet-like structure produced by functionalization with the HPDMIM(C1) ionic liquid. The maximum specific capacitance achieved for the HPDMIM(C1):CuO hybrid electrode was 464 F g-1 at 5 mV s-1 in a 1 M Na2SO4 electrolyte. Thus, our findings, in addition to the stability of the HPDMIM(C1):CuO, indicate that it is a candidate for energy-storage applications.

Adsorptive remediation of cobalt oxide nanoparticles by magnetized α-cellulose fibers from waste paper biomass.

Remediation of engineered-nanomaterials is an up-coming major environmental concern. This study demonstrates adsorptive-remediation of cobalt oxide nanoparticles (CoO NPs) from the water. The α-cellulose-fibers were extracted from waste-paper biomass (WP-αCFs) and magnetized with Fe3O4 NPs (M-WP-αCFs). The XRD, FT-IR, and TGA were performed for detailed characterization of the newly developed bioadsorbent. The M-WP-αCFs was then applied for adsorptive remediation of CoO NPs. The adsorptive kinetics of CoO NPs adsorption onto the M-WP-αCFs reveals the pseudo-second-order model. The various adsorption isotherm studies revealed Langmuir is a best-fit isotherm. A prominently high adsorption capacity qm (1567 mg/g) corroborated extraordinary adsorptive potential of M-WP-αCFs. Furthermore, CoO NPs were adsorbed onto M-WP-αCFs were analyzed by the XPS, VSM, and TEM. Therefore, this study gave rise WP biomass extracted and rapidly-separable nano-biocomposite of 'M-WP-αCFs' with a high-capacity for CoO NPs remediation and can be further applied in remediation of several other engineered-nanomaterials.

Chlamydomonas angulosa (Green Alga) and Nostoc commune (Blue-Green Alga) Microalgae-Cellulose Composite Aerogel Beads: Manufacture, Physicochemical Characterization, and Cd (II) Adsorption.

This study presents composite aerogel beads prepared by mixing dissolved cellulose with Chlamydomonas angulosa and Nostoc commune cells, respectively, at 0.1, 0.3, and 0.5% (w/w). The manufactured composites (termed regenerated cellulose (RC)), with C. angulosa (RCCA-(1, 3, and 5)), and with N. commune (RCNC-(1, 3, and 5)) were analyzed. Both RCCA-5 and RCNC-5 showed the high specific surface area to be about 261.3 and 332.8 m²·g-1. In the microstructure analysis, network structures were observed in the cross-sections of RC, RCCA-5, and RCNC-5. The pyrolysis temperature of the RCCA-5 and RCNC-5 composite aerogel beads was rapidly increased about 250 °C during the mixing of cellulose with C. angulosa and N. commune. The chemical analysis of RC, RCCA-5, and RCNC-5 showed peaks corresponding to various functional groups, such as amide, carboxyl, and hydroxyl groups from protein, lipid, and carbohydrate. RCNC-5 at pH 6 demonstrated highest Cd2+ removal rate about 90.3%, 82.1%, and 63.1% at 10, 25, and 50 ppm Cd2+, respectively. At pH 6, Cd2+ adsorption rates per unit weight of the RCNC-5 were about 0.9025, 2.0514, and 3.1547 mg/g at 10, 25, and 50 ppm, respectively. The peaks assigned to the amide, carboxyl, and hydroxyl groups in RCCA-5, RCNC-5, and RC were shifted or disappeared immediately after adsorption of Cd2+. The specific surface area, total pore volume, and mean pore diameter of composites was decreased due to adsorption of Cd2+ on the developed materials. As can be seen in the X-ray powder diffraction (XRD) spectrum, significant changes in the molecular structure of the composite aerogel beads were not observed even after adsorption of Cd2+.

Paper waste extracted α-cellulose fibers super-magnetized and chitosan-functionalized for covalent laccase immobilization.

Enormous disposal of paper wastes (PW) causing number of environmental problems. PW is efficiently used to extract multifunctional α-cellulose fibers (αCFs). Thus, αCFs extraction from PW, and functionalization with Fe3O4 and chitosan were successfully performed for immobilization of laccase. Therefore, in this investigation, PW extracted αCFs were tuned with supermagnetic Fe3O4 (M) and functionalized with chitosan (CTA) (M-PW-αCF-CTA). Furthermore, M-PW-αCF-CTA was glutaraldehyde cross-linked for covalent laccase immobilization. The synthesized materials were characterized by FT-IR, TGA, FE-SEM, FE-HR-TEM and VSM analyzes. M-PW-αCF-CTA exhibited magnetic saturation value of 14.72 emu/g. Laccase immobilized on M-PW-αCF-CTA (M-PW-αCF-CTA-Lac) gave 92% of activity recovery and loading capacity of 73.30 mg/g. M-PW-αCF-CTA-Lac showed excellent pH, temperature, and storage stabilities with the exceptional reusability potential. Moreover, M-PW-αCF-CTA-Lac was applied for repeated removal of carcinogenic Direct Red 28 (DR28). Therefore, M-PW-αCF-CTA-Lac is green and economical biocatalyst with extraordinary separation potential can be enforced for environmental pollutants reclamation.

Cellulose⁻Chitosan Antibacterial Composite Films Prepared from LiBr Solution.

Cellulose and chitosan solutions were prepared in 60% LiBr and mixed with a different weight ratio. The washing and drying of the prepared cellulose⁻chitosan composite films were performed under identical conditions. The color of the liquefied mixtures and films was initially transparent but changed from colorless to brownish yellow depending on the ratio of chitosan in the solution. The cross section observed in the SEM results indicated that the film developed with a higher ratio of chitosan was more robust and possessed greater antibacterial properties. FT-IR analysis of the films showed that hydrogen bonds between cellulose and chitosan in composite films were successfully achieved and retained excellent mechanical properties. The proper ratio of chitosan in the cellulose solution can increase the tensile strength and improve the elongation of the films; however, the E-modulus property was consistently reduced. The antibacterial activity and mechanical properties of the films were greatly improved as the amount of chitosan in the film increased.

Long-term trends in intraocular pressure after combined vitrectomy with sub-tenon injection of triamcinolone acetonide.

PURPOSE: To evaluate the long-term effect of vitrectomy by itself and combined vitrectomy with sub-Tenon injection of triamcinolone acetonide (TA) on intraocular pressure (IOP). METHODS: In a retrospective cohort study, the medical records of 56 eyes of 56 patients who underwent nonemergent vitrectomy and were followed up for at least 24 months were reviewed. Thirty-two eyes of 32 patients underwent combined vitrectomy with sub-Tenon injection of TA. Twenty-four eyes of 24 patients underwent vitrectomy only. Increased IOP of >4 mmHg from the baseline, change in IOP from the baseline, and preoperative and postoperative measured IOPs were recorded and compared between the two groups, and with fellow eyes. RESULTS: Minimum follow-up period was 24 months. Except the IOP at postoperative 1 day, there were no significant differences between vitrectomized eyes and nonvitrectomized fellow eyes. There were also no differences between vitrectomized eyes and eyes that underwent combined vitrectomy with sub-Tenon injection of TA. And in the comparison of the vitrectomy-only eye group and the vitrectomy with sub-Tenon TA eye group, there was also no significant difference during the whole follow-up period. CONCLUSION: Vitrectomy by itself or combined vitrectomy with sub-Tenon injection of TA does not seem to increase IOP in the long term.

The effects of nicergoline on corneal nerve regeneration in rat corneas after photorefractive keratectomy.

PURPOSE: We wanted to investigate the effect of nicergoline on corneal nerve regeneration in rat corneas after photorefractive keratectomy (PRK). METHODS: Twenty Sprague-Dawley male rats were divided into two groups, the control group and the group that had been treated with nicergoline for 4 weeks. Corneal wound healing was evaluated by fluorescein staining after PRK. Immunofluorescent staining was performed in the rat corneas at 1 month after PRK with monoclonal antibodies for class III ß-tubulin, calcitonin gene-related peptide (CGRP), and substance P (SP). The stained nerve areas were calculated using an image-analysis program. RESULTS: The corneal wound healing rate was not significantly different between the nicergoline-treated rats and the control rats after PRK. At 1 month after PRK, the tubulin-positive, substance P-positive, and CGRP-positive nerve areas were significantly greater in the treatment group than those in the control group. CONCLUSION: Nicergoline treatment increased the corneal nerve area in the rats after they had undergone PRK. Nicergoline may help patients who have a decreased corneal sense, such as those with neurotrophic keratopathy and those patients after they undergo refractive surgery.

Safety of moxifloxacin and voriconazole in corneal storage media on porcine corneal endothelial cells.

PURPOSE: The aim of this study was to evaluate the safety of moxifloxacin and voriconazole as a supplement in corneal storage media for porcine corneal endothelial cells. METHODS: Twenty-eight eyes were divided into 4 groups. In the control group (the C group), corneal buttons were stored for 3 days in Optisol-GS. In the treatment group, the corneal buttons were preserved for 3 days in Optisol-GS mixed with 250 microg/mL moxifloxacin (M group), 100 microg/mL voriconazole (V group), and 250 microg/mL moxifloxacin plus 100 microg/mL voriconazole (MV group). We evaluated the samples via specular microscopy before and after 3 days of preservation. The mean changes of endothelial cell counts were compared among the 4 groups. Scanning electron microscopy was conducted after 3 days of preservation. RESULTS: Before the preservation, the endothelial cell counts did not differ among the 4 groups (P > 0.05). After 3 days of preservation, the endothelial cell count in the MV group was the lowest among the 4 groups (P < 0.05). After 3 days of preservation, the rate of corneal endothelial cell loss in the M and V groups did not differ significantly from the control group (P > 0.05). The rate of endothelial cell loss in the MV group was significantly higher than that of the control group (P < 0.05). Scanning electron microscopy revealed a normal mosaic pattern for the C, V, and F groups, but hexagonality was not preserved in the MV group. CONCLUSION: Preservation in Optisol-GS mixed with moxifloxacin (250 microg/mL) plus voriconazole (100 microg/mL) induced significant toxicity on the endothelial cells in porcine corneas, when compared with the control group.

Effect of a single intraoperative sub-Tenon injection of triamcinolone acetonide on the progression of diabetic retinopathy and visual outcomes after cataract surgery.

PURPOSE: To assess the effect of a single intraoperative sub-Tenon injection of triamcinolone acetonide on the progression of diabetic retinopathy (DR), visual outcomes, and cystoid macular edema (CME) after cataract surgery. SETTING: Department of Ophthalmology and Visual Science, College of Medicine, The Catholic University of Korea, Seoul, Korea. METHODS: This prospective controlled study comprised 46 eyes of 23 diabetic patients. The control group comprised eyes not treated with a triamcinolone acetonide injection, and the triamcinolone group comprised contralateral eyes treated with a single posterior sub-Tenon injection of triamcinolone acetonide at the end of cataract surgery. The visual acuity, central macular thickness (CMT) by optical coherence tomography, and progression of DR were compared between the 2 groups. RESULTS: One month postoperatively, the mean change in lines of best corrected visual acuity was significantly greater in the triamcinolone group (P = .045) and the mean change in CMT was significantly greater in the control group (P = .015). The incidence of CME was higher in the control group (P = 0.04). Scores for progression of DR at 6 months were not statistically significantly different between the 2 groups (P = 0.08). CONCLUSIONS: A posterior sub-Tenon injection of triamcinolone acetonide lowered the incidence of CME after cataract surgery in diabetic patients, improved visual recovery, and reduced the amount of CMT increase in the short term (< or = 1 month postoperatively). However, triamcinolone acetonide did not affect DR progression over the 6-month follow-up.

Hydrogen peroxide-induced cell death in a human retinal pigment epithelial cell line, ARPE-19.

The loss of retinal pigment epithelium (RPE) with aging is related to age-related macular degeneration (AMD). This study was conducted to investigate the mechanism of hydrogen peroxide (H2O2) induced cell death in a human retinal pigment epithelial cell line, ARPE-19. Hydrogen peroxide was added at different concentrations to ARPE-19 cells and cultured. The cytotoxicity was assayed by mitochondrial function using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) testing. The patterns of cell damage were assessed using an acridine orange-ethidium bromide differential staining method, in situ end labeling (ISEL) assay and transmission electron microscopy (TEM). Catalase, a major antioxidant, was used to prevent cell death. The cleavage of procaspase 3 and poly (ADP-ribose) polymerase (PARP) was determined by western blot analysis. Hydrogen peroxide significantly induced cell death in ARPE-19 cells, whereas pretreatment of the cells with catalase prevented cell death. Application of the ISEL assay and acridine orange/ethidium bromide staining demonstrated that the H2O2-induced cell death occurred by an apoptotic mechanism at lower concentrations of H2O2 (400, 500, 600 microM), whereas higher concentrations of H2O2 induced necrosis rather than apoptosis. Caspase 3 was associated with the apoptotic pathway in human RPE cell death. Western blot analysis confirmed caspase 3 activation and cleavage of substrate proteins in ARPE-19 cells treated with an H2O2 concentration of 600 microM. These results indicate that treatment with H2O2 induces apoptotic and necrotic cell death in ARPE-19, and that caspase 3 is associated with apoptotic cell death. Therefore, H2O2 may induce the destruction of RPE cells in AMD by the combined effects of apoptosis and necrosis.