Curcumin Sustained Release with a Hybrid Chitosan-Silk Fibroin Nanofiber Containing Silver Nanoparticles as a Novel Highly Efficient Antibacterial Wound Dressing

Drug loading in electrospun nanofibers has gained a lot of attention as a novel method for direct drug release in an injury site to accelerate wound healing. The present study deals with the fabrication of silk fibroin (SF)-chitosan (CS)-silver (Ag)-curcumin (CUR) nanofibers using the electrospinning method, which facilitates the pH-responsive release of CUR, accelerates wound healing, and improves mechanical properties. Response surface methodology (RSM) was used to investigate the effect of the solution parameters on the nanofiber diameter and morphology. The nanofibers were characterized via Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), zeta potential, and Dynamic Light Scattering (DLS). CS concentration plays a crucial role in the physical and mechanical properties of the nanofibers. Drug loading and entrapment efficiencies improved from 13 to 44% and 43 to 82%, respectively, after the incorporation of Ag nanoparticles. The application of CS hydrogel enabled a pH-responsive release of CUR under acid conditions. The Minimum Inhibitory Concentration (MIC) assay on E. coli and S. aureus bacteria showed that nanofibers with lower CS concentration cause stronger inhibitory effects on bacterial growth. The nanofibers do not have any toxic effect on cell culture, as revealed by in vitro wound healing test on NIH 3T3 fibroblasts

Isolation and molecular characterization of a novel Na + /H + antiporter gene, AlNHX2, from Aeluropus littoralis and comparison of AlNHX1 and AlNHX2

Abstract Halophytes have high tolerance against salinity and it is expected that these plants have special proteins that allow them to thrive under salinity conditions. Hence, to understand molecular aspects of vacuolar Na + /H + antiporter, which has a possible role in salt tolerance in halophytic plants, a novel Na + /H + antiporter gene, AlNHX2, was isolated and characterized by rapid amplification of cDNA ends (RACE) technique. The results revealed that AlNHX2 is expressed in leaves, stems and roots and its expression in leaves is 1.767 and 1.269 times higher than stems and roots, respectively. This gene has an ORF with 1617 bp in length, a 3'-UTR region with 245 pb, and a 5'-UTR region with 187 bp which encodes a 538 amino acid protein shared a high homology with those putative vacuolar Na + /H + antiporters of higher plants. Putative phosphorylation sites within AlNHX1 and AlNHX2 were determined using the prediction software, and the binding of 14-3-3 protein to specific domains within AlNHX1 and AlNHX2 was predicted. The results also revealed this binding is induced by a protein kinase-mediated phosphorylation of a specific Thr or Ser residue in these domains. The results also revealed that the activities of AlNHX1 and AlNHX2 are regulated by PKC, p38MAPK and GSK3. In addition, the findings reported here show the interaction of CaM protein with C-terminal of AlNHX2. Autoinhibitory domain at C-terminal region of AlNHX2 that can suppress the protein activity under normal growth conditions was also found

Bioremediation capability and characterization of bacteria isolated from petroleum contaminated soils in Iran

This study was carried out to isolate bacteria for bioremediation of petroleum polluted soils. Five samples were used for isolation in this study. They were four soil samples in addition to one kerosene sample. The soil samples including soils contaminated by crude oil and gas oil and two soil samples with no outward contamination which were collected from Shiraz Oil Refinery sites. Seven strains were selected among the isolated colonies for further experiments. The selected isolates were cultured in standard succinate medium (SSM) minimal medium in which 2.5% v/v kerosene was used as carbon source. In another bacterial SSM culture, carbon, sulfur or nitrogen source was removed and 20% v/v kerosene added to check the ability of isolates to utilizekerosene as sole source for C, N and S. Finally, cultures of four strains with higher growth in modified SSM cultures were selected for GC analysis. In this study they were named C2 and C4 which were isolated from crude oil contaminated soil and SI1 and SI2 isolated from soils with no outward contamination. GC analysis showed that C2 could degrade 69% of 5% v/v kerosene in 7 d, while C4 and SI1 degraded 48% and 42% of 5% v/v kerosene during this 7-d period respectively, and the degradation ability of SI2 was 38% after 7 d. Analysis of 16S rRNA gene showed that C2 was close to Citrobacter sedlakii, C4 and SI1 were related to Entrobacter hormeachei and SI2 was close to Entrobacter cloacae, respectively

Successful treatment of allergic conjunctival granuloma by topical tacrolimus: A clinicopathologic case report

Allergic conjunctival granuloma is a rare cause of conjunctival ocular lesions. The aim of this case report was to present a successful treatment of an allergic conjunctival granuloma with topical tacrolimus eye drops. A 20-year-old female presented with bilateral multiple yellow nodules of the bulbar conjunctival epithelium and conjunctival injection. The patient had tearing, photophobia, itching, foreign body sensation, and red eye. The patient's signs and symptoms progressed despite the use of topical steroids. The patient was treated by application of tacrolimus eye drop (0.005%) in her right eye every 6 h while the left eye was put on placebo. Her signs and symptoms were recorded at each visit. After 3 weeks' therapy with topical tacrolimus eye drop, the patient became asymptomatic in her right eye and conjunctival granulomas fully resolved. Topical tacrolimus seems to be an effective therapeutic option for the treatment of allergic conjunctival granulomas

Biomass and lipid induction strategies in microalgae for biofuel production and other applications

The use of fossil fuels has been strongly related to critical problems currently affecting society, such as: global warming, global greenhouse effects and pollution. These problems have affected the homeostasis of living organisms worldwide at an alarming rate. Due to this, it is imperative to look for alternatives to the use of fossil fuels and one of the relevant substitutes are biofuels. There are different types of biofuels (categories and generations) that have been previously explored, but recently, the use of microalgae has been strongly considered for the production of biofuels since they present a series of advantages over other biofuel production sources: (a) they don’t need arable land to grow and therefore do not compete with food crops (like biofuels produced from corn, sugar cane and other plants) and; (b) they exhibit rapid biomass production containing high oil contents, at least 15 to 20 times higher than land based oleaginous crops. Hence, these unicellular photosynthetic microorganisms have received great attention from researches to use them in the large-scale production of biofuels. However, one disadvantage of using microalgae is the high economic cost due to the low-yields of lipid content in the microalgae biomass. Thus, development of different methods to enhance microalgae biomass, as well as lipid content in the microalgae cells, would lead to the development of a sustainable low-cost process to produce biofuels. Within the last 10 years, many studies have reported different methods and strategies to induce lipid production to obtain higher lipid accumulation in the biomass of microalgae cells; however, there is not a comprehensive review in the literature that highlights, compares and discusses these strategies. Here, we review these strategies which include modulating light intensity in cultures, controlling and varying CO2 levels and temperature, inducing nutrient starvation in the culture, the implementation of stress by incorporating heavy metal or inducing a high salinity condition, and the use of metabolic and genetic engineering techniques coupled with nanotechnology

Ocular safety of intravitreal ethylene diamine tetra acetic acid (EDTA): An experimental feasibility study

Ethylene diamine tetra acetic acid (EDTA) is a chelating component that is able to diminish oxidative reactivity and can be a potential neuroprotective drug in various ocular diseases. For assessing the safety of intravitreal EDTA, 10 rabbits were allocated and divided into 5 groups. Right eyes of the animals received intravitreal EDTA (112.5, 225, 450, 900 and 1800 µg /0.1 ml). Fellow eyes were considered as controls. Clinical examinations and electroretinography (ERG) were performed at the baseline and on day 28. The enucleated eyes were subjected to hematoxylin and eosin (H&E) staining, immunohistochemistry for glial fibrillary acidic protein (GFAP) and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) test. Clinical examinations, H&E staining and TUNEL assay were unremarkable. The ERG test did not exhibit any significant alteration compared to the baseline values, except for a significant decrease in just one measurement of the eyes injected with 225 µg EDTA. The mean scores of GFAP immune reactivity in the eyes injected with 112.5 and 225 µg EDTA indicated a non-significant reaction. The scores in higher doses were significant. We suggest intravitreal EDTA with a dose threshold of < 450 µg should be studied for ratification of the safe dose

Development of a Theoretical Model That Predicts Optothermal Energy Conversion of Gold Metallic Nanoparticles

Gold nanoparticles (AuNPs) can be found in different shapes and sizes, which determine their chemical and physical characteristics. Physical and chemical properties of metallic NPs can be tuned by changing their shape, size, and surface chemistry; therefore, this has led to their use in a wide variety of applications in many industrial and academic sectors. One of the features of metallic NPs is their ability to act as optothermal energy converters, where they absorb light at a specific wavelength and heat up their local nanosurfaces. This feature has been used in many applications where metallic NPs get coupled with thermally responsive systems to trigger an optical response. In this study, we synthesized AuNPs that are spherical in shape with an average diameter of 20.07 nm. This work assessed simultaneously theoretical and experimental techniques to evaluate the different factors that affect heat generation at the surface of AuNPs when exposed to a specific light wavelength. The results indicated that laser power, concentration of AuNPs, time × laser power interaction, and time illumination, were the most important factors that contributed to the temperature change exhibited in the AuNPs solution. We report a regression model that allows predicting heat generation and temperature changes with residual standard errors of less than 4%. These results are highly relevant in the future design and development of applications where metallic NPs are incorporated into systems to induce a temperature change triggered by light exposure