Intramolecular hydrogen transfer in DNA induced by site-selective resonant core excitation.

We present experimental evidence for soft X-ray induced intramolecular hydrogen transfer in the protonated synthetic tri-oligonucleotide (UAG) in the gas-phase (U: fluorouracil). The trinucleotide cations were stored in a cryogenic ion trap and exposed to monochromatic synchrotron radiation. Photoionization and photofragmentation product ion yields were recorded as a function of photon energy.

Site-selective soft X-ray absorption as a tool to study protonation and electronic structure of gas-phase DNA.

The conformation and the electronic structure of gas-phase oligonucleotides depends strongly on the protonation site. 5'-d(FUAG) can either be protonated at the A-N1 or at the G-N7 position. We have stored protonated 5'-d(FUAG) cations in a cryogenic ion trap held at about 20 K.

Stoichiometric control of the density of states in PbS colloidal quantum dot solids.

Colloidal quantum dots, and nanostructured semiconductors in general, carry the promise of overcoming the limitations of classical materials in chemical and physical properties and in processability. However, sufficient control of electronic properties, such as carrier concentration and carrier mobility, has not been achieved until now, limiting their application. In bulk semiconductors, modifications of electronic properties are obtained by alloying or doping, an approach that is not viable for structures in which the surface is dominant.

SAINT-liposome-polycation particles, a new carrier for improved delivery of siRNAs to inflamed endothelial cells.

Interference with acute and chronic inflammatory processes by means of delivery of siRNAs into microvascular endothelial cells at a site of inflammation demands specific, non-toxic and effective siRNA delivery system. In the current work we describe the design and characterization of siRNA carriers based on cationic pyridinium-derived lipid 1-methyl-4-(cis-9-dioleyl)methyl-pyridinium-chloride) (SAINT-C18) and the transfection enhancer protamine, complexed with siRNA/carrier DNA or siRNA only. These carriers, called SAINT-liposome-polycation-DNA (S-LPD) and SAINT-liposome-polycation (S-LP), have a high efficiency of siRNA encapsulation, low cellular toxicity, and superior efficacy of gene downregulation in endothelial cells in vitro as compared to DOTAP-LPD.