Removal of lead ions from aqueous solution using new magnetic metal-organic framework.

In this research, new magnetic nanocomposites that consist of NH2-MIL53 (Al) and Fe3O4 nanoparticles functionalized with cysteine were synthesized and characterized. The application of these nanocomposites was investigated to remove lead ions from the wastewater model. The concentration of metal ions was measured by the utilization of flame atomic absorption spectroscopy (FAAS). Also, XRD, SEM, EDX, and FTIR instruments were used to identification and characterization of the synthesized nanocomposites. The effect of operating parameters such as; pH, contact time and adsorbent dosage were investigated on lead removal. The synthesized nanocomposite showed great potential for lead removal. The maximum adsorption capacity of the nanocomposite was about 361.53 mg/g. Adsorption kinetic parameters well fitted with the pseudo-second order kinetic model. The reusability test of the synthesized magnetic absorbent showed good adsorption efficiency for at least three consecutive cycles.

The Role of Inflammatory Cytokines in Neovascularization of Chemical Ocular Injury.

AIM: Chemical injuries can potentially lead to the necrosis anterior segment of the eye, and cornea in particular. Inflammatory cytokines are the first factors produced after chemical ocular injuries. Inflammation via promoting the angiogenesis factor tries to implement the wound healing mechanism in the epithelial and stromal layer of the cornea. METHODS: Narrative review. RESULTS: In our review, we described the patterns of chemical injuries in the cornea and their molecular mechanisms associated with the expression of inflammatory cytokines. Moreover, the effects of inflammation signals on angiogenesis factors and CNV were explained. CONCLUSION: The contribution of inflammation and angiogenesis causes de novo formation of blood vessels that is known as the corneal neovascularization (CNV). The new vascularity interrupts cornea clarity and visual acuity. Inflammation also depleted the Limbal stem cells (LSCs) in the limbus causing the failure of normal corneal epithelial healing and conjunctivalization of the cornea.

The effect of N-acetyl cysteine and doxycycline on TNF-α-Rel-a inflammatory pathway and downstream angiogenesis factors in the cornea of rats injured by 2-chloroethyl-ethyl sulfide.

BACKGROUND: Cornea injury of sulfur mustard (SM) is considered as the most devastating injuries to the eye. This study aimed to evaluate the single and combined effects of N-acetyl cysteine (NAC) and doxycycline on the inflammatory pathway and cornea neovascularization (CNV) in the rat model of SM-injured cornea. MATERIALS AND METHODS: The right cornea of male Sprague-Dawley rats was subjected to 2-chloroethyl-ethyl sulfide (CEES). Rats were topically treated with a single and combined of 0.5% NAC and 12.5 µg/ml doxycycline and examined at 3rd, 15th, and 21st days. The activity of three antioxidant enzymes was analyzed in the cornea of different groups. Real-time PCR was performed to measure gene expression of inflammatory factors (tnf-α, rel-a & cxcl-1) and angiogenesis factors (vegf-a, mmp2,9) in the cornea lysates. The histological and opacity assessments were also carried out. RESULTS: The activity of antioxidant enzymes significantly declined 3 days after the CEES damage. NAC eye drop recovered the enzyme activity on the 21st day of treatment (p-value < .05). The expression of tnf-α and rel-a genes significantly increased after CEES cornea exposure, while NAC declined their expression on the 7th and 21st days. The CNV score and angiogenesis factor expression were decreased in the long term by single and combined treatments (p-value < .05), but the infiltration of inflammatory cells was not completely amended. CONCLUSION: NAC and doxycycline eye drop could improve the CNV complication. Also, NAC was an effective treatment against the inflammatory pathway involved in CEES-injured cornea.

Effects of Xenogen Mesenchymal Stem Cells and Cryo-Platelet Gel on Intractable Wound Healing in Animal Model (Rat).

BACKGROUND: Today, the effects of growth factors and mesenchymal stem cells (MSCs) in promoting wound healing has been confirmed. OBJECTIVE: This study aimed to investigate the effect of MSCs and platelet cryogel on wound healing. METHODS: 40 male wistar rats were randomly divided into five groups (n=8). The control group was just dressed, the second group received platelet cryogel, the third group received platelet cryogel containing MSCs, the fourth group received plasma, and the fifth group received plasma plus MSCs. The biopsy was obtained from the wounds in the 2, 4, 6, and 8 days of the treatment. Then, pathological evaluation was conducted. Finally, qRT-PCR was performed to determine angiogenesis. RESULTS: The intervention groups had faster wound healing and lower wound area than the control group (p<0.05). The highest wound healing rate and the smallest wound area was observed in the group receiving platelet cryogel plus MSCs. Angiogenesis, fibrosis, myoepithelial and epithelialization in the pathologic examination using H & E staining were not significantly different between the groups. The expression of Ang-1 in the intervention groups was higher than the control group and the highest expression was observed in the platelet cryogel plus MSCs, followed by the platelet cryogel group. The expression of VEGF in the plasma plus MSCs was higher than in the other groups. CONCLUSION: Further studies require to determine the effects of combined use of platelet cryogel plus MSCs on other types of wound and evaluate mechanisms involved in wound healing like collagenesis and inflammatory factors.

Fabrication of the robust and recyclable tyrosinase-harboring biocatalyst using ethylenediamine functionalized superparamagnetic nanoparticles: nanocarrier characterization and immobilized enzyme properties.

Immobilized tyrosinase onto the functionalized nanoparticles with the ability to be reused easily in different reaction cycles to degrade phenolic compounds is known as a substantial challenge, which can be overcome through surface modification of the particles via proper chemical groups. Herein, the synthesis and silica coating of superparamagnetic nanoparticles using a simple procedure as well as their potential for tyrosinase immobilization were demonstrated. Therefore, N-[3-(trimethoxysilyl)propyl]ethylenediamine was used to functionalize the silica-coated nanoparticles with amine groups. Then, the ethylenediamine functionalized magnetic nanoparticles (EMNPs) were suspended in a solution containing tetrahydrofuran and cyanuric chloride (as an activating agent) to modify nanocarriers. To immobilize enzyme, a mixture of tyrosinase and cyanuric chloride functionalized magnetic nanoparticle (Cyc/EMNPs) was shaken at room temperature. The particles were characterized by EDX, TGA, SEM, FTIR, and TEM. As a result, the successful functionalization of the magnetic nanoparticles and covalent attachment of tyrosinase onto the Cyc/EMNPs were confirmed. The fabricated nano-biocatalyst particles were semi-spherical in shape. The immobilized tyrosinase (Ty-Cyc/EMNPs) exhibited remarkable reusability of six consecutive reaction cycles while no considerable loss of activity was observed for the first three cycles. Moreover, the excellent stability of the biocatalyst at different temperatures and pHs was proved. The Ty-Cyc/EMNPs with interesting features are promising for practical applications in biosensor development and wastewater treatment.

Biotransformation of phenol in synthetic wastewater using the functionalized magnetic nano-biocatalyst particles carrying tyrosinase.

Low conversion efficiency and long-processing time are some of the major problems associated with the use of biocatalysts in industrial processes. In this study, modified magnetic iron oxide nanoparticles bearing tyrosinase (tyrosinase-MNPs) were employed as a magnetic nano-biocatalyst to treat phenol-containing wastewater. Different factors affecting the phenol removal efficiency of the fabricated nano-biocatalyst such as catalyst dosage, pH, temperature, initial phenol concentration, and reusability were investigated. The results proved that the precise dosage of nano-biocatalyst was able to degrade phenol at the wide range of pHs and temperatures. The immobilized tyrosinase showed proper phenol degradation more than 70%, where the substrate with a high concentration of 2500 mg/L was subjected to phenol removal. The nano-biocatalyst was highly efficient and reusable, since it displayed phenol degradation yields of 100% after the third reuse cycle and about 58% after the seventh cycle. Moreover, the immobilized tyrosinase was able to degrade phenol dissolved in real water samples up to 78% after incubation for 60 min. It was also reusable at least seven cycles in the real water sample. The results proved the effectiveness and applicability of the fabricated nano-biocatalyst to treat phenol-containing wastewaters in a shorter time and higher efficiency even at high phenol concentration. The developed nano-biocatalyst can be promising for the micropollutants removal and an alternative for the catalysts used in traditional treatment processes.

Covalent immobilization of tyrosinase onto cyanuric chloride crosslinked amine-functionalized superparamagnetic nanoparticles: Synthesis and characterization of the recyclable nanobiocatalyst.

Magnetic nanoparticles (MNPs) were synthesized using the chemical co-precipitation method. Then the nanoparticles were coated with silica via hydrolysis of tetraethyl orthosilicate using the sol-gel process. The silica coated magnetic nanoparticles were amine-functionalized with 3-aminopropyltriethoxysilane/ethanol solution. Subsequently, the nanoparticles were added to a solution of cyanuric chloride in tetrahydrofuran to synthesize cyanuric chloride-functionalized magnetic nanoparticles (Cy-MNPs). For covalent immobilization of tyrosinase, Cy-MNPs were added to a freshly prepared tyrosinase solution and the mixture was shaken. The FTIR spectra, as well as EDX, analysis proved the covalent immobilization of tyrosinase on the nanoparticles. The magnetic properties of tyrosinase-immobilized magnetic nanoparticles (tyrosinase-MNPs) were specified by VSM analysis. TEM images indicated that the most of the tyrosinase-MNPs had a semi-spherical shape with an average size of 17nm. The synthesized nanoparticles had a high loading capacity of 194mg tyrosinase/g nanoparticles with an immobilization yield of 69%. The optimum condition for both free and immobilized tyrosinase was found at pH 7.0 and 35°C. The immobilized enzyme was active after treatment of the particles at various pHs and temperatures for 100min. In addition, reusability of the immobilized enzyme was investigated and it was proved its suitability to be used for more than 7 cycles. Also, tyrosinase-MNPs remained about 70% of its initial activity after storing at 4°C for 40days. This nanobiocatalyst with interesting properties is promising for practical application in wastewater treatment and biosensor development.

Data in support of covalent attachment of tyrosinase onto cyanuric chloride crosslinked magnetic nanoparticles.

Preparation and characterization of cross linked amine-functionalized magnetic nanoparticles as an appropriate support for covalent immobilization on tyrosinase was presented in the study "Covalent immobilization of tyrosinase onto cyanuric chloride crosslinked amine-functionalized superparamagnetic nanoparticles: synthesis and characterization of the recyclable nanobiocatalyst" (Abdollahi et al., 2016 ) [1]. Herein, complementary data regarding X-ray powder diffraction (XRD) to characterize the synthesized magnetic nanoparticles, and transmission electron microscopy (TEM) to determine the size and morphology of tyrosinase immobilized magnetic nanoparticles (tyrosinase-MNPs) were reported. The purification results of the extracted tyrosinase from mushroom Agaricus bisporus were provided in a purification table. The covalent immobilization of tyrosinase onto cyanuric chloride functionalized magnetic nanoparticles was proved by performing thermo-gravimetric and energy-dispersive X-ray spectroscopy analyses. The operational stability of immobilized tyrosinase was investigated by incubating tyrosinase-MNPs at different pH and temperatures.

Virulence factors, serogroups and antimicrobial resistance properties of Escherichia coli strains in fermented dairy products.

BACKGROUND: From a clinical perspective, it is essential to know the microbial safety of fermented dairy products. Doogh and kashk are fermented dairies. These products are used by millions of people but their microbial qualities are unknown. Shiga toxin producing Escherichia coli (STEC) is one of the most commonly detected pathogens in the cases of food poisoning and food-borne illnesses. The present investigation was carried out in order to study the molecular characterization and antimicrobial resistance properties of STEC strains isolated from fermented dairy products. METHODS: Six hundred fermented dairy samples were collected and immediately transferred to the laboratory. All samples were cultured immediately and those that were E. coli-positive were analyzed for the presence of O157 , O26, O103, O111, O145, O45, O91, O113, O121 and O128 STEC serogroups, tetA, tetB, blaSHV, CITM, cmlA, cat1, aadA1, dfrA1, qnr, aac (3)-IV, sul1 and ereA antibiotic resistance genes and stx1, stx2, eaeA, ehly, cnf1, cnf2, iutA, cdtB, papA, traT, sfaS and fyuA virulence factors using PCR. Antimicrobial susceptibility testing was performed also using disk diffusion methodology with Mueller-Hinton agar. RESULTS: Fifty out of 600 (8.33%) dairy samples harbored E. coli. In addition, yoghurt was the most commonly contaminated dairy. O157 (26%) and O26 (12%) were the most commonly detected serogroups. A significant difference was found between the frequency of Attaching and Effacing E. coli and Enterohaemorrhagic E. coli (P <0.05). Stx1 (44%), eae (36%), papA (32%) stx2 (30%), and ehly (28%) were the most commonly detected virulence factors. The genes encode resistance against tetracycline (tetA and tetB) (76% and 70%, respectively), cephalothin (blaSHV) (38%), ampicillin (CITM) (36%) and gentamicin (aac (3)-IV) (32%) were the most commonly detected. High resistance levels to tetracycline (84%), penicillin (46%), ampicillin (38%) and streptomycin (36%) were observed. CONCLUSION: Fermented dairy products can easily become contaminated by antibiotic resistant STEC strains. Our findings should raise awareness about antibiotic resistance in Iran. Clinicians should exercise caution when prescribing antibiotics, especially in veterinary treatments.