Marianna Gniadek

Tannic acid modified silver nanoparticles show antiviral activity in herpes simplex virus type 2 infection.

The interaction between silver nanoparticles and herpesviruses is attracting great interest due to their antiviral activity and possibility to use as microbicides for oral and anogenital herpes. In this work, we demonstrate that tannic acid modified silver nanoparticles sized 13 nm, 33 nm and 46 nm are capable of reducing HSV-2 infectivity both in vitro and in vivo. The antiviral activity of tannic acid modified silver nanoparticles was size-related, required direct interaction and blocked virus attachment, penetration and further spread. All tested tannic acid modified silver nanoparticles reduced both infection and inflammatory reaction in the mouse model of HSV-2 infection when used at infection or for a post-infection treatment. Smaller-sized nanoparticles induced production of cytokines and chemokines important for anti-viral response. The corresponding control buffers with tannic acid showed inferior antiviral effects in vitro and were ineffective in blocking in vivo infection. Our results show that tannic acid modified silver nanoparticles are good candidates for microbicides used in treatment of herpesvirus infections.

Modification of Electrode Surfaces: Deposition of Thin Layers of Polypyrrole−Au Nanoparticle Materials Using a Combination of Interphase Synthesis and Dip-in Method

Formation of thin layers of the composite material by a method based on interphase polymerization induced by a transport-controlled redox reaction is described. The obtained films were of 0.2-1 microm thickness, consisted of polypyrrole and gold nanoparticles (up to 13.5 at. %), strongly adhered to the substrate surface, and were uniform. Different carbon materials and glass wool were employed as the substrates. The first step in the synthesis was deposition of an organic layer on the substrate. This was followed by dipping the substrate in an aqueous solution containing an oxidizer and appropriate washing and drying the composite film.

Optimizing calcium selective fluorimetric nanospheres

Recently it was shown that optical nanosensors based on alternating polymers e.g. poly(maleic anhydride-alt-1-octadecene) were characterized by a linear dependence of emission intensity on logarithm of concentration over a few of orders of magnitude range. In this work we focus on the material used to prepare calcium selective nanosensors. It is shown that alternating polymer nanosensors offer competitive performance in the absence of calcium ionophore, due to interaction of the nanospheres building blocks with analyte ions. The emission increase corresponds to increase of calcium ions contents in the sample within the range from 10(-4) to 10(-1) M. Further improvement in sensitivity (from 10(-6) to 10(-1) M) and selectivity can be achieved by incorporating calcium ionophore in the nanospheres. The optimal results were obtained for core-shell nanospheres, where the core was prepared from poly(styrene-co-maleic anhydride) and the outer layer from poly(maleic anhydride-alt-1-octadecene). Thus obtained chemosensors were showing linear dependence of emission on logarithm of calcium ions concentration within the range from 10(-7) to 10(-1) M.

Toxicity of tannic acid-modified silver nanoparticles in keratinocytes: potential for immunomodulatory applications

Hydrolyzable tannins are known to exhibit anti-inflammatory activity, which can be used in combination with silver nanoparticles (AgNPs) for dermal uses. In this study, we investigated the effects of tannic acid-modified 13, 33, 46nm and unmodified 10-65nm AgNPs using the human-derived keratinocyte HaCaT and VK2-E6/E7 cell lines in the form of stationary and spheroids cultures. After exposition to tannic acid-modified AgNPs, VK2-E6/E7 cells showed higher toxicity, increased production of reactive oxygen species (ROS) and activity of JNK stress kinase, while HaCaT cell line demonstrated less ROS production and activation of ERK kinase. AgNPs internalization was detected both in the superficial and internal layers of spheroids prepared from both cell lines. Tannic acid modified AgNPs sized above 30nm did not induce DNA breaks in comet assay performed in both cell lines. Tannic acid-modified but not unmodified AgNPs down-regulated TNF-α and LPS-triggered production of IL-8 in VK2-E6/E7 but not in HaCaT cells. In summary, tannic acid-modified AgNPs sized above 30nm show good toxicological profile both in vitro and possess immunomodulatory properties useful for potential dermal applications in humans.

Polypyrrole–gold nanostructured composite, active and durable electrocatalytic material

The consequences of treatment of gold nanocrystals present in polypyrrole–gold composites and electrodeposited gold nanocrystals (PPY–Au and Au NPs) with OH radicals generated in Fenton’s reaction were investigated. Particularly, the changes in the morphology and the electrochemical properties of those materials are shown. For both materials, the etching effect was noticed. Contrary to significantly reduced catalytic activity, the changes observed in size and shape of gold nanostructures were less pronounced. In the case of PPY–Au composite material, the etching effects were less intense. Even after a 60-min radical treatment of the PPY–Au composite material, the gold–nanocrystal catalytic activity remained high. The limited dissolution of the gold nanocrystals in the PPY–Au composites, compared to bare Au NPs, can be explained by the presence of the polymer which served as a kind of protective barrier against the oxidizing agent. A decrease in the electrocatalytic properties vs. the electrooxidation of ethanol of both forms of gold nanocrystals were observed after the treatment with hydroxyl radicals.

Physical and chemical changes in Alhydrogel™ damaged by freezing

Accidental freezing of aluminum-based vaccines occurs during their storage and transportation, in both developed and developing countries. Freezing damages the freeze-sensitive aluminum adjuvanted vaccines, through separation of lattice between aluminum adjuvant and antigen, leading to formation of aluminum aggregates, and loss of potency. In this study, we examined Alhydrogel™ ([AlO(OH)]xnH2O, aluminum hydroxide, hydrated for adsorption) stored under recommended conditions, and exposed to freezing temperature until solid-frozen. The main purpose of our research was to determine the destruction areas of the solid-frozen Alhydrogel™ using selected methods of scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, Fourier-transform infrared spectroscopy and transmission electron microscopy working in diffraction mode. The Zeta potential evaluation, measurements of albumin adsorption power, thermogravimetric analysis and estimation of the mass loss after drying indicated significant structural (physical) and chemical differences between the freeze-damaged and non-frozen vaccine adjuvant. The presented results are important to better understand the type and nature of damages occurring in freeze-damaged aluminum-based vaccines. These results can be used in future studies to improve the temperature stability of aluminum adjuvanted vaccines.

Tannic Acid-Modified Silver and Gold Nanoparticles as Novel Stimulators of Dendritic Cells Activation

Silver nanoparticles (AgNPs) are promising new antimicrobial agents against a wide range of skin and mucosal pathogens. However, their interaction with the immune system is currently not fully understood. Dendritic cells (DCs) are crucial during development of T cell-specific responses against bacterial and viral pathogens. We have previously shown that tannic acid-modified silver nanoparticles (TA-AgNPs) consist of a promising microbicide against HSV-2. The aim of this study was to compare the ability of TA-AgNPs or TA-AuNPs of similar sizes (TA-Ag/AuNPs) to induce DCs maturation and activation in the presence of HSV-2 antigens when used at non-toxic doses. First, we used JAWS II DC line to test toxicity, ultrastructure as well as activation markers (MHC I and II, CD40, CD80, CD86, PD-L1) and cytokine production in the presence of TA-Ag/AuNPs. Preparations of HSV-2 treated with nanoparticles (TA-Ag/AuNPs-HSV-2) were further used to investigate HSV-2 antigen uptake, activation markers, TLR9 expression, and cytokine production. Additionally, we accessed proliferation and activation of HSV-2-specific T cells by DCs treated with TA-AgNP/AuNPs-HSV-2. We found that both TA-AgNPs and TA-AuNPs were efficiently internalized by DCs and induced activated ultrastructure. Although TA-AgNPs were more toxic than TA-AuNPs in corresponding sizes, they were also more potent stimulators of DCs maturation and TLR9 expression. TA-Ag/AuNPs-HSV-2 helped to overcome inhibition of DCs maturation by live or inactivated virus through up-regulation of MHC II and CD86 and down-regulation of CD80 expression. Down-regulation of CD40 expression in HSV-2-infected DCs was reversed when HSV-2 was treated with TA-NPs sized >30 nm. On the other hand, small-sized TA-AgNPs helped to better internalize HSV-2 antigens. HSV-2 treated with both types of NPs stimulated activation of JAWS II and memory CD8+ T cells, while TA-AgNPs treatment induced IFN-γ producing CD4+ and CD8+ T cells. Our study shows that TA-AgNPs or TA-AuNPs are good activators of DCs, albeit their final effect upon maturation and activation may be metal and size dependent. We conclude that TA-Ag/AuNPs consist of a novel class of nano-adjuvants, which can help to overcome virus-induced suppression of DCs activation.