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Herpes simplex virus type 1 (HSV-1) is a common virus of mankind and HSV-1 infections are a significant cause of blindness. The current antiviral treatment of herpes infection relies on acyclovir and related compounds. However, acyclovir resistance emerges especially in the long term prophylactic treatment that is required for prevention of recurrent herpes keratitis. Earlier we have established antiviral siRNA swarms, targeting sequences of essential genes of HSV, as effective means of silencing the replication of HSV in vitro or in vivo. In this study, we show the antiviral efficacy of 2´-fluoro modified antiviral siRNA swarms against HSV-1 in human corneal epithelial cells (HCE). We studied HCE for innate immunity responses to HSV-1, to immunostimulatory cytotoxic double stranded RNA, and to the antiviral siRNA swarms, with or without a viral challenge. The panel of studied innate responses included interferon beta, lambda 1, interferon stimulated gene 54, human myxovirus resistance protein A, human myxovirus resistance protein B, toll-like receptor 3 and interferon kappa. Our results demonstrated that HCE cells are a suitable model to study antiviral RNAi efficacy and safety in vitro. In HCE cells, the antiviral siRNA swarms targeting the HSV UL29 gene and harboring 2´-fluoro modifications, were well tolerated, induced only modest innate immunity responses, and were highly antiviral with more than 99% inhibition of viral release. The antiviral effect of the 2’-fluoro modified swarm was more apparent than that of the unmodified antiviral siRNA swarm. Our results encourage further research in vitro and in vivo on antiviral siRNA swarm therapy of corneal HSV infection, especially with modified siRNA swarms.

Chemical modifications of small interfering (si)RNAs are used to enhance their stability and potency, and to reduce possible off-target effects, including immunogenicity. We have earlier introduced highly effective antiviral siRNA swarms against herpes simplex virus (HSV), targeting 653 bp of the essential UL29 viral gene. Here, we report a method for enzymatic production and antiviral use of 2′-fluoro-modified siRNA swarms. Utilizing the RNA-dependent RNA polymerase from bacteriophage phi6, we produced 2′-F-siRNA swarms containing either all or a fraction of modified adenosine, cytidine or uridine residues in the antisense strand of the UL29 target. The siRNA containing modified pyrimidines demonstrated high resistance to RNase A and the antiviral potency of all the UL29-specific 2′-F-siRNA swarms was 100-fold in comparison with the unmodified counterpart, without additional cytotoxicity. Modest stimulation of innate immunity signaling, including induced expression of both type I and type III interferons, as well as interferon-stimulated gene 54, by 2′-F-cytidine and 2′-F-uridine modified siRNA swarms occurred at early time points after transfection while the 2′-F-adenosine-containing siRNA was similar to the unmodified antiviral siRNA swarm in this respect. The antiviral efficacy of the 2′-F-siRNA swarms and the elicited cellular innate responses did not correlate suggesting that innate immunity pathways do not significantly contribute to the observed enhanced antiviral activity of the modified siRNAs. The results support further applications of enzymatically produced siRNA molecules with incorporated adenosine nucleotides, carrying fluoro-modification on ribose C2′ position, for further antiviral studies in vitro and in vivo., Graphical abstract Image 1, Highlights • Phage phi6 polymerase can use 2′-F-dNTP substrates to produce 2′-F-modified dsRNA. • SiRNAs containing 2′-F-modified pyrimidine nucleotides demonstrate resistance to RNase A. • Enzymatically produced 2′-F-siRNA swarms display low cytotoxicity. • Antiviral activity of 2′-F-siRNAs against HSV exceeds that of the unmodified siRNAs. • Innate immunity induction by 2′-F-siRNAs is similar to that of unmodified siRNAs.

Reduction of graphene oxide (GO) with vanadium(III) trichloride under various reaction conditions has been investigated. The results show that V(III) can be used as an efficient reducing agent for GO in aqueous solutions at low concentrations and in moderate temperatures under ambient conditions. The IR spectroscopy and X-ray photoelectron spectroscopy (XPS) show that the structure of the vanadium-reduced material is similar to reduced graphene oxide prepared using TiCl3 or hydrazine as a reducing agent. The electrical conductivity of the material is also similar in all cases. However, on the basis of the XPS results, vanadium-based reduction does not leave significant reductant impurities in the product and does not lead to graphene substitution reactions. The success of vanadium(III) is somewhat surprising because the formal redox potential of the V(IV)/V(III) pair is rather anodic, but spectrophotometric studies of the reaction unambiguously showed that the process is a redox reaction. This method introduces a new facile graphene oxide reduction technique, which can be applied under ambient aqueous conditions.

Novel metal-organic frameworks [Eu2L3(DMSO)2(MeOH)2] x 2 DMSO x 3 H2O, 1, and [Zn2L2(DMSO)2] x 1.6 H2O, 2, (L = 4,4'-ethyne-1,2-diyldibenzoate) have been synthesized and structurally characterized. Compound 1 is a 3D open framework while 2 features interpenetrating 2D sheets in the crystal lattice. Both compounds have been characterized with X-ray crystallography, elemental analysis, and thermogravimetric analysis. Compounds 1 and 2 are red and blue-green luminescent, respectively, in the solid state at ambient temperature. Thermogravimetric analysis implies that the extensive interpenetration stabilizes the lattice of 2, although it diminishes the porosity at the same time. The luminescence of 1 can be reversibly quenched and restored by the addition and removal of iodine.

We report the formation of a tetrapallada-macrocycle induced by an unusual transmetallation, in which an anionic bidentate chelate ligand is replaced by a phenyl ligand from phenylboronic acid, leaving the chloride ligands intact.