We demonstrate a strong enhancement in the antimicrobial and antifungal action of berberine encapsulated in nanogel carriers whose surface is functionalised with a cationic polyelectrolyte. The effect comes from the electrostatic adhesion of the cationic nanocarriers on the cell wall.

We explore the effects of the particle size and the surface charge of polyelectrolyte-coated titania nanoparticles on their toxicity towards green microalgae and yeast cells in UV/vis light.

We demonstrate a strong enhancement of the antimicrobial action of chlorhexidine which is attributed to the electrostatic adhesion of the cationic nanocarriers on the microbial cell walls which leads to their accumulation and local delivery of chlorhexidine directly on to the microbial cell membrane.

In the present work, we investigated novel, green, and facile approach for the synthesis of stable silver nanoparticles by use of inexpensive and available Iraqi Zahdi palm dates extract as reducing and stabilizing agents. The formation and color change of dark brown suspension of silver nanoparticles were monitored and examined by ultraviolet-visible spectrophotometric analysis at maximum wavelength of 401 nm. The produced nanoparticles were characterized by dynamic light scattering (DLS), Fourier transform-infrared spectrometry (FTIR), atomic force microscope (AFM), X-ray diffraction (XRD) and scanning electron microscopy (SEM)-energy dispersive spectroscopy (EDS). The results demonstrated that particle size distribution was around 90 ± 40 nm which was in line with grain size of the nanoparticles measured by AFM, while the crystallite size was about 20 nm according to the results observed from XRD technique. Additionally, the zeta potential of synthesized silver nanoparticles was found to be nearly about -25 mV, whereby the suspension showed high stability upon storing the sample in a cool place for a long period of time. The synthesized silver nanoparticles exhibited efficient antibacterial activity against pathogenic methicillin-resistant Staphylococcus aureus (MRSA) bacteria. They also showed enhanced anticancer activity against breast cancer cells (MCF7) with high apoptotic effect as compared with normal MCF10A cells, which confirmed the biocompatible nature of green synthesized silver nanoparticles. It is considered that nanosilver particles synthesized with palm dates extract may basically establish a significant step to synthesize such nanoparticles for topical applications as well as an alternative anticancer drug of existing chemotherapeutics of cancer..

Silver nanoparticles have been considered as powerful antimicrobial agents recently, especially with the increasing incidence of diseases associated with biofilm and multi-drug resistant pathogens. The aim of this study was to synthesize silver nanoparticles by biological and chemical methods and combination with imipenem to eradicate biofilm-forming bacteria at phenotypic and genotypic levels. The biosynthesis of silver nanoparticles was done by using Enterobacter cloacae (cell-free suspension) while chemosynthesis was conducted using sodium borohydride. Biological and chemical silver nanoparticles were characterized by ultraviolet-visible spectrophotometry which showed absorbance peak at 400 and 390nm respectively. Fourier transformer infrared analysis revealed that carboxylic and polyphenolic groups were coated on surface of both silver nanoparticles. Scanning electron microscope and size analyser showed that the sizes of biologically and chemically silver nanoparticles were 63 nm and 25 nm, respectively. In addition, it showed the formation of cubical nanoparticles. The antimicrobial effect of synthesized silver nanoparticles were evaluated by agar well diffusion and macrodilution method to determine minimum inhibitory concentration value. The results showed that biological silver nanoparticles were more effective on biofilm forming bacteria (Serratia fonticola and Pantoea sp.) than chemical synthesized ones. In addition, the combination effect between silver nanoparticles and imipenem displayed synergistic effect. Gene expression of biofilm encoding genes (smaI and esaL) were evaluated by real-time quantitative polymerase chain reaction (RT-qPCR) before and after treatment with silver nanoparticles in both types and imipenem and in combination between them. The results revealed that biological silver nanoparticles alone or in combination with antibiotics were more effective on biofilm gene expression by down regulation than other treatments.

We investigated the effects of short-term exposure of bare TiO 2 NPs and polyelectrolyte-coated TiO 2 NPs in the 5-25 nm size range, at relatively high concentrations (of 500 and 1000 mg/L) under light or dark conditions, in D. rerio embryos. The biological endpoints investigated included embryo viability and mRNA transcript levels of antioxidant and membrane transport genes relative to control embryos. The presence of nanoparticles on the surface of embryos was assessed using TEM. The results confirm an accumulation of TiO 2 NPs on the outer surface (chorion) of the embryo, but not within the embryo. No significant difference in embryo viability was detected following each exposure regime. The expression of antioxidant biomarker, SOD2, was significantly impacted by the type of TiO 2 NP, with TiO 2 NPs/PSS/PAH coating exposure showing down regulation; the concentration of the nanoparticles, with down regulation at 500 mg/L; and dark/light condition with down regulation in the light. The expression levels of the hypoxia and membrane markers, HIF1 and Pxmp2, were not significantly impacted by any factor. The study indicates that SOD2 mRNA expression levels may be useful in the detection of apparent oxidative stress induced by the titania nanoparticle build up on the embryo chorion surface.

Silver nanoparticles have been considered a powerful antimicrobial agents recently especially after increasing incidence of diseases associated with biofilm and multi-drug resistant pathogens required to find a novel path to eradicate that challenge. The present study aims to evaluate the antibacterial activity of biosynthesized silver nanoparticles (AgNPs) using a cell-free extract of Enterobacter cloacae and chemo synthesis by sodium borohydride (NaBH 4 ) on biofilm-forming Pseudomonas oryzihabitans. Antimicrobial effect of silver nanoparticles in both types and in combination with imipenem were evaluated by agar well diffusion method. The results revealed a good response to inhibit biofilm-forming Pseudomonas oryzihabitans growth by silver nanoparticles antibacterial activity in both types (biological and chemical) and in combination with imipenem; the antimicrobial effect was increased and enhanced. In the present study, it was found that the biological and chemical silver nanoparticles were considered a novel and decisive solution against biofilm and multi-drug resistance bacteria with a preference of biological silver nanoparticles.

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