scholarly journals Size- and concentration-dependence of antiviral and virucidal activity of Au nanoparticles against adenoviruses and influenza viruses H1N1

2021 ◽  
Author(s):  
Maryna Chaika ◽  
Krystyna Naumenko ◽  
Yuliia Pankivska ◽  
Olga Povnitsa ◽  
Iuliia Mukha ◽  
...  

Over the past 10 years, many scientific groups have experimentally shown that non-functionalized nanoparticles show a pronounced antiviral and antimicrobial action against different pathogens. In order to understand the mechanism of nanoparticles action it is important to know its peculiarities, i.e. dependences on different nanoparticles and pathogen properties.In this work we studied how Au nanoparticles act on the viruses outside and inside the cell, and compare this action for two sizes of nanoparticles and two types of the viruses. The study has been conducted for adenovirus and H1N1 influenza virus, and nanoparticles of 5 nm and 20 nm diameter.Virucidal and antiviral actions were observed experimentally for both types of nanoparticles against both viruses. It has been shown that intensity of virucidal action depends on the nanoparticles concentration non-monotonically for adenovirus. It has also been shown with electron microscopy that the viruses are destructed after 5 nm nanoparticles adsorption on their surface; and that the viruses change their shape after 20 nm nanoparticles adsorption on their surface. The model of physical adsorption of nanoparticles on the virus surface due to near-field interaction proposed in previous works may explain observed results on virucidal action of nanoparticles.

2015 ◽  
Vol 77 (8) ◽  
Author(s):  
Omer A. Alawi ◽  
Nor Azwadi Che Sidik ◽  
Rizalman Mamat

The past decade has seen rapid development of nanofluids science in many aspects. In recent years, refrigerant-based nanofluids have been introduced as nanorefrigerants due to their significant effects over heat transfer performance. In this investigation, the Control Volume based Finite Element Method (CVFEM) is used to simulate the natural convection heat transfer of nanorefrigerant in cylindrical horizontal annuli with imposed temperatures in both surfaces. The Maxwell–Garnetts (MG) and Brinkman models are also employed to estimate the effect of thermal conductivity and viscosity of nanorefrigerant. The governing parameters are nanoparticles types, nanoparticles concentration and size, effect of Rayleigh numbers (Ra), eccentricity and rotation of inner cylinder. Results are presented in the form of isotherms and streamlines of nanorefrigerant temperature and velocity. The results indicate that Al2O3/R141b with concentration (2%) and nanoparticles size (20 nm) has the best heat transfer performances. Moreover, the heat transfer and fluid flow enhance by increasing the Rayleigh numbers (Ra). Eccentricity and rotation of inner cylinder also have effects on heat transfer characteristics. 


2016 ◽  
Vol 90 (9) ◽  
pp. 4720-4734 ◽  
Author(s):  
Donald M. Carter ◽  
Christopher A. Darby ◽  
Bradford C. Lefoley ◽  
Corey J. Crevar ◽  
Timothy Alefantis ◽  
...  

ABSTRACTOne of the challenges of developing influenza A vaccines is the diversity of antigenically distinct isolates. Previously, a novel hemagglutinin (HA) for H5N1 influenza was derived from a methodology termed computationally optimized broadly reactive antigen (COBRA). This COBRA HA elicited a broad antibody response against H5N1 isolates from different clades. We now report the development and characterization of a COBRA-based vaccine for both seasonal and pandemic H1N1 influenza virus isolates. Nine prototype H1N1 COBRA HA proteins were developed and tested in mice using a virus-like particle (VLP) format for the elicitation of broadly reactive, functional antibody responses and protection against viral challenge. These candidates were designed to recognize H1N1 viruses isolated within the last 30 years. In addition, several COBRA candidates were designed based on sequences of H1N1 viruses spanning the past 100 years, including modern pandemic H1N1 isolates. Four of the 9 H1N1 COBRA HA proteins (X1, X3, X6, and P1) had the broadest hemagglutination inhibition (HAI) activity against a panel of 17 H1N1 viruses. These vaccines were used in cocktails or prime-boost combinations. The most effective regimens that both elicited the broadest HAI response and protected mice against a pandemic H1N1 challenge were vaccines that contained the P1 COBRA VLP and either the X3 or X6 COBRA VLP vaccine. These mice had little or no detectable viral replication, comparable to that observed with a matched licensed vaccine. This is the first report describing a COBRA-based HA vaccine strategy that elicits a universal, broadly reactive, protective response against seasonal and pandemic H1N1 isolates.IMPORTANCEUniversal influenza vaccine approaches have the potential to be paradigm shifting for the influenza vaccine field, with the goal of replacing the current standard of care with broadly cross-protective vaccines. We have used COBRA technology to develop an HA head-based strategy that elicits antibodies against many H1 strains that have undergone genetic drift and has potential as a “subtype universal” vaccine. Nine HA COBRA candidates were developed, and these vaccines were used alone, in cocktails or in prime-boost combinations. The most effective regimens elicited the broadest hemagglutination inhibition (HAI) response against a panel of H1N1 viruses isolated over the past 100 years. This is the first report describing a COBRA-based HA vaccine strategy that elicits a broadly reactive response against seasonal and pandemic H1N1 isolates.


2016 ◽  
Vol 8 (5) ◽  
pp. 64 ◽  
Author(s):  
Saad F. Oboudi ◽  
Mustafa Q. AL-Habeeb

<p class="1Body">Superconductor samples were prepared by a conventional solid-state reaction method and systematically studied for their superconducting properties. The Au nanoparticles concentration x varied from 0.0 to 1.0 wt% of the sample's total mass. Those samples were used as targets to prepare Au<sub>x</sub>–Bi<sub>1.7</sub>Pb<sub>0.3</sub>Sr<sub>2</sub>Ca<sub>2</sub>Cu<sub>3</sub>O<sub>10+δ</sub> thin films by pulsed laser deposition (PLD), deposited on Si (111) substrates and post-deposition oxygen annealing have been achieved. The effect of Au nanoparticles (20 nm) on the physical properties of superconducting phase was studied. The phase identification/gross structural characteristics of synthesized bulk and thin films samples explored through powder X-ray diffractometer and reveals that all the samples crystallize in orthorhombic structure In addition, phase examination by XRD indicated that Au nanoparticles enhanced the (Bi,Pb)-2223 phase formation. The critical transition temperature (<em>T<sub>c</sub></em>) measured by the standard DC four-probe method and was found to have optimal value at x=1.0 wt%, which had a maximum enhancement in <em>T<sub>c</sub></em> for both bulk and thin films samples. The surface morphology investigated through scanning electron microscope (SEM) and atomic force microscopy (AFM), the granular investigation showed that both number and size of voids decreased while grains size increased as x increases to 1.0 wt%.</p>


2018 ◽  
Author(s):  
Adrian Cernescu ◽  
Michał Szuwarzyński ◽  
Urszula Kwolek ◽  
Karol Wolski ◽  
Paweł Wydro ◽  
...  

<div><div>Scattering-mode Scanning Near-Field Optical Microscopy (sSNOM) allows one to obtain absorption spectra in the mid-IR region for samples as small as 20 nm in size. This configuration has made it possible to measure FTIR spectra of the protein complement of membranes. (Amenabar 2013) We now show that mid-IR sSNOM has the sensitivity required to measure spectra of phospholipids in individual bilayers in the spectral range 800 cm<sup>-1</sup>–1400 cm<sup>-1</sup>. We have observed the main absorption bands of the dipalmitoylphosphatidylcholine headgroups in this spectral region above noise level. We have also mapped the phosphate absorption band at 1070 cm<sup>-1</sup> simultaneously with the AFM topography. We have shown that we could achieve sufficient contrast to discriminate between single and multiple phospholipid bilayers and other structures, such as liposomes. This work opens the way to further research that uses nano-IR spectroscopy to describe the biochemistry of cell membranes and model systems.</div></div><div></div>


2012 ◽  
Vol 87 (3) ◽  
pp. 1400-1410 ◽  
Author(s):  
Donald M. Carter ◽  
Chalise E. Bloom ◽  
Eduardo J. M. Nascimento ◽  
Ernesto T. A. Marques ◽  
Jodi K. Craigo ◽  
...  

ABSTRACTIndividuals <60 years of age had the lowest incidence of infection, with ∼25% of these people having preexisting, cross-reactive antibodies to novel 2009 H1N1 influenza. Many people >60 years old also had preexisting antibodies to novel H1N1. These observations are puzzling because the seasonal H1N1 viruses circulating during the last 60 years were not antigenically similar to novel H1N1. We therefore hypothesized that a sequence of exposures to antigenically different seasonal H1N1 viruses can elicit an antibody response that protects against novel 2009 H1N1. Ferrets were preinfected with seasonal H1N1 viruses and assessed for cross-reactive antibodies to novel H1N1. Serum from infected ferrets was assayed for cross-reactivity to both seasonal and novel 2009 H1N1 strains. These results were compared to those of ferrets that were sequentially infected with H1N1 viruses isolated prior to 1957 or more-recently isolated viruses. Following seroconversion, ferrets were challenged with novel H1N1 influenza virus and assessed for viral titers in the nasal wash, morbidity, and mortality. There was no hemagglutination inhibition (HAI) cross-reactivity in ferrets infected with any single seasonal H1N1 influenza viruses, with limited protection to challenge. However, sequential H1N1 influenza infections reduced the incidence of disease and elicited cross-reactive antibodies to novel H1N1 isolates. The amount and duration of virus shedding and the frequency of transmission following novel H1N1 challenge were reduced. Exposure to multiple seasonal H1N1 influenza viruses, and not to any single H1N1 influenza virus, elicits a breadth of antibodies that neutralize novel H1N1 even though the host was never exposed to the novel H1N1 influenza viruses.


Vaccines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 793
Author(s):  
Ying Huang ◽  
Monique S. França ◽  
James D. Allen ◽  
Hua Shi ◽  
Ted M. Ross

Vaccination is the best way to prevent influenza virus infections, but the diversity of antigenically distinct isolates is a persistent challenge for vaccine development. In order to conquer the antigenic variability and improve influenza virus vaccine efficacy, our research group has developed computationally optimized broadly reactive antigens (COBRAs) in the form of recombinant hemagglutinins (rHAs) to elicit broader immune responses. However, previous COBRA H1N1 vaccines do not elicit immune responses that neutralize H1N1 virus strains in circulation during the recent years. In order to update our COBRA vaccine, two new candidate COBRA HA vaccines, Y2 and Y4, were generated using a new seasonal-based COBRA methodology derived from H1N1 isolates that circulated during 2013–2019. In this study, the effectiveness of COBRA Y2 and Y4 vaccines were evaluated in mice, and the elicited immune responses were compared to those generated by historical H1 COBRA HA and wild-type H1N1 HA vaccines. Mice vaccinated with the next generation COBRA HA vaccines effectively protected against morbidity and mortality after infection with H1N1 influenza viruses. The antibodies elicited by the COBRA HA vaccines were highly cross-reactive with influenza A (H1N1) pdm09-like viruses isolated from 2009 to 2021, especially with the most recent circulating viruses from 2019 to 2021. Furthermore, viral loads in lungs of mice vaccinated with Y2 and Y4 were dramatically reduced to low or undetectable levels, resulting in minimal lung injury compared to wild-type HA vaccines following H1N1 influenza virus infection.


Vaccines ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 47 ◽  
Author(s):  
Raffael Nachbagauer ◽  
Florian Krammer ◽  
Randy Albrecht

Influenza viruses cause severe diseases and mortality in humans on an annual basis. The current influenza virus vaccines can confer protection when they are well-matched with the circulating strains. However, due to constant changes of the virus surface glycoproteins, the vaccine efficacy can drop substantially in some seasons. In addition, the current seasonal influenza virus vaccines do not protect from avian influenza viruses of human pandemic potential. Novel influenza virus vaccines that aim to elicit antibodies against conserved epitopes like the hemagglutinin stalk could not only reduce the burden of drifted seasonal viruses but potentially also protect humans from infection with zoonotic and emerging pandemic influenza viruses. In this paper, we generated influenza virus vaccine constructs that express chimeric hemagglutinins consisting of exotic, avian head domains and a consistent stalk domain of a seasonal virus. Using such viruses in a sequential immunization regimen can redirect the immune response towards conserved epitopes. In this study, male ferrets received a live-attenuated vaccine virus based on the A/Ann Arbor/6/60 strain expressing a chimeric H8/1 (cH8/1) hemagglutinin, which was followed by a heterologous booster vaccination with a cH5/1N1 formalin inactivated non-adjuvanted whole virus. This group was compared to a second group that received a cH8/1N1 inactivated vaccine followed by a cH5/1N1 inactivated vaccine. Both groups showed a reduction in viral titers in the upper respiratory tract after the A(H1N1)pdm09 virus challenge. Animals that received the live-attenuated vaccine had low or undetectable titers in the lower respiratory tract. The results support the further development of chimeric hemagglutinin-based vaccination strategies. The outcome of this study confirms and corroborates findings from female ferrets primed with a A/Leningrad/134/17/57-based live attenuated cH8/1N1 vaccine followed by vaccination with an AS03-adjuvanted cH5/1N1 split virus vaccine 10.


2014 ◽  
Vol 95 (11) ◽  
pp. 2372-2376 ◽  
Author(s):  
Andi Krumbholz ◽  
Jeannette Lange ◽  
Andreas Sauerbrei ◽  
Marco Groth ◽  
Matthias Platzer ◽  
...  

The avian-like swine influenza viruses emerged in 1979 in Belgium and Germany. Thereafter, they spread through many European swine-producing countries, replaced the circulating classical swine H1N1 influenza viruses, and became endemic. Serological and subsequent molecular data indicated an avian source, but details remained obscure due to a lack of relevant avian influenza virus sequence data. Here, the origin of the European avian-like swine influenza viruses was analysed using a collection of 16 European swine H1N1 influenza viruses sampled in 1979–1981 in Germany, the Netherlands, Belgium, Italy and France, as well as several contemporaneous avian influenza viruses of various serotypes. The phylogenetic trees suggested a triple reassortant with a unique genotype constellation. Time-resolved maximum clade credibility trees indicated times to the most recent common ancestors of 34–46 years (before 2008) depending on the RNA segment and the method of tree inference.


Nature ◽  
2009 ◽  
Vol 460 (7258) ◽  
pp. 1021-1025 ◽  
Author(s):  
Yasushi Itoh ◽  
Kyoko Shinya ◽  
Maki Kiso ◽  
Tokiko Watanabe ◽  
Yoshihiro Sakoda ◽  
...  

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