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ED pattern of gold standard solution (blue) superimposed on the experimental ED pattern obtained from AuNPs analysis (red)
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Gold nanoparticles (AuNPs) have been exploited for a wide range of potential applications, including drug delivery systems, catalysts, optical sensors and antimicrobial agents [1-5]. However, the harsh conditions employed in several synthetic approaches has forced researchers to investigate milder routes [6]. Biological macromolecules such as prote...
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... size tunability of the AuNPs was later verified by TEM measurements to display correlation between UV-Vis data and corresponding incubation times (Table 1, Figs. 1 & 2). The metallic nature of the AuNPs was confirmed by superimposing the ED pattern obtained from the experimental samples with that of the gold standard (Fig. 5). The spherical shape of the AuNPs was determined by eucentric tilting. In order to ensure experimental reproducibility, the concentration of DNA used to yield the AuNPs was maintained constant. This was necessary since, upon dilution of the DNA concentration by 50 fold, a progressive broadening of the UV-Vis spectra of the NP was ...
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Citations
... However, in this study, the high positive charge on the AgNP-pIREGFP-H5 surface made it more likely to adhere to the cell membrane and interfere with cellular function.18 The size of the nanoencapsulated plasmid is dictated by several parameters that influence the particle formation mechanism, eg, the G-C versus A-T content and the degree of topological purity of the plasmid suspension.19 It has been suggested that particles less than about 150 nm in diameter are preferred for endocytosis.3,20 ...
In order to develop a systemically administered safe and effective nonviral gene delivery system against avian influenza virus (AIV) that induced cytokine expression, the hemagglutinin (H5) gene of AIV, A/Ck/Malaysia/5858/04 (H5N1) and green fluorescent protein were cloned into a coexpression vector pIRES (pIREGFP-H5) and formulated using green synthesis of silver nanoparticles (AgNPs) with poly(ethylene glycol) and transfected into primary duodenal cells taken from 18-day-old specific-pathogen-free chick embryos. The AgNPs were prepared using moderated temperature and characterized for particle size, surface charge, ultraviolet-visible spectra, DNA loading, and stability. AgNPs and AgNP-pIREGFP-H5 were prepared in the size range of 13.9 nm and 25 nm with a positive charge of +78 ± 0.6 mV and +40 ± 6.2 mV, respectively. AgNPs with a positive surface charge could encapsulate pIREGFP-H5 efficiently. The ultraviolet-visible spectra for AgNP-pIREGFP-H5 treated with DNase I showed that the AgNPs were able to encapsulate pIREGFP-H5 efficiently. Polymerase chain reaction showed that AgNP-pIREGFP-H5 entered into primary duodenal cells rapidly, as early as one hour after transfection. Green fluorescent protein expression was observed after 36 hours, peaked at 48 hours, and remained stable for up to 60 hours. In addition, green fluorescent protein expression generally increased with increasing DNA concentration and time. Cells were transfected using Lipocurax in vitro transfection reagent as a positive control. A multiplex quantitative mRNA gene expression assay in the transfected primary duodenal cells via the transfection reagent and AgNPs with pIREGFP-H5 revealed expression of interleukin (IL)-18, IL-15, and IL-12â.
... A control sample prepared in the same way in the absence of MBI did not show these darker areas in the image. Since a carbon-coated grid was used and carbon nanotubes are present in the mixture, the Netcounts method (sample area minus control area) [34] is not used. As a result, the X-ray scattered lines from the copper grid show up in the background of the spectrum. ...
In recent years, toroidal nanostructures have become an appealing topic in nanoscience owing to their unique structure and promising applications. Among them, polymeric toroidal self-assemblies have attracted considerable attention because of their manipulability and diversity. Despite the substantial advances in the area of polymeric nanotoroids, the universal formation principles and functions of these toroids have not been sufficiently summarized. This article aims to review recent advances in the formation and function of polymeric nanotoroids. The significant role of theoretical simulations in revealing the formation mechanism and inherent structure of toroidal assemblies is emphasized. Additionally, a perspective on the challenges of this research field is addressed.
Recent efforts in bio-inspired Au nanomaterial synthesis have identified that Trp residues of Au binding peptides AuBP1 (WAGAKRLVLRRE) and AuBP2 (WALRRSIRRQSY) have the capacity to drive metal ion reduction. Such a capability could be intrinsically valuable for material production under sustainable conditions that limits the number of reagents re-quired for nanoparticle generation. Additionally, it could also allow for precise localization of inorganic materials based upon peptide positioning. These advances in material peptide design could prove to be significant for applications in catalysis, sensing, plasmonic, etc. Herein we examine this reduction capability of tryptophan modified peptides to identify strategies to incorporate such reactivity into non-reactive peptides to enhance their individual functionality for material production. This is examined using peptide mutation studies that incorporate Au3+ reductive Trp residues into non-reactive materials binding peptides. The results demonstrate that reactivity can be incorporated into non-functional biomolecules where the location of the Trp, the neighboring residues in direct contact with the Trp, and the complete sequence all can be tuned to greatly modulated Au3+ reduction reactivity. Additionally, the binding strength of the peptide to the free metal ions in solu-tion is shown to alter the reactivity where stronger affinity between the biomolecules and metal ions leads to diminished reduction. Taken together, these results present pathways toward selective biological modifications of material directing pep-tides to increase their inherent capabilities for the design, production, and stabilization of functional inorganic nanomaterials.
In order to develop a systemically administered safe and effective nonviral gene
delivery system against avian influenza virus (AIV) that induced cytokine expression, the
hemagglutinin (H5) gene of AIV, A/Ck/Malaysia/5858/04 (H5N1) and green fluorescent
protein were cloned into a coexpression vector pIRES (pIREGFP-H5) and formulated using
green synthesis of silver nanoparticles (AgNPs) with poly(ethylene glycol) and transfected
into primary duodenal cells taken from 18-day-old specific-pathogen-free chick embryos.
The AgNPs were prepared using moderated temperature and characterized for particle size,
surface charge, ultraviolet-visible spectra, DNA loading, and stability. AgNPs and AgNP-
pIREGFP-H5 were prepared in the size range of 13.9 nm and 25 nm with a positive charge
of +78 ± 0.6 mV and +40 ± 6.2 mV, respectively. AgNPs with a positive surface charge could
encapsulate pIREGFP-H5 efficiently. The ultraviolet-visible spectra for AgNP-pIREGFP-H5
treated with DNase I showed that the AgNPs were able to encapsulate pIREGFP-H5 efficiently.
Polymerase chain reaction showed that AgNP-pIREGFP-H5 entered into primary duodenal
cells rapidly, as early as one hour after transfection. Green fluorescent protein expression was
observed after 36 hours, peaked at 48 hours, and remained stable for up to 60 hours. In addition,
green fluorescent protein expression generally increased with increasing DNA concentration
and time. Cells were transfected using Lipocurax in vitro transfection reagent as a positive
control. A multiplex quantitative mRNA gene expression assay in the transfected primary
duodenal cells via the transfection reagent and AgNPs with pIREGFP-H5 revealed expression
of interleukin (IL)-18, IL-15, and IL-12β.
