Nanoparticles for RNA Interference

Efficient and safe protein nanoparticles for the targeted delivery of small molecule, protein and oligonucleotide based drugs will play a key role in the field of science in the upcoming years. Whereas viral and liposomal formulations have been extensively tested throughout the last two decades, their inherent and in the case of viruses sometimes even fatal obstacles not seldom seem impossible to conquer. The time for the development of a new therapeutic option in form of an advanced drug delivery system within pharmaceutical technology, biopharmacy and clinical studies has come. In our eyes gelatin based nanoparticles with polysaccharide and peptide modifications are an optimum to fulfil this need and will therefore be the center of the research presented in this work. Basically, nanoparticles with a size from 150 to 300 nm were prepared by desolvating a clear solution of gelatin through dropwise addition of an organic anti-solvent under heavy stirring. A subsequent destabilization of the water soluble protein chains resulted in round particles with a homogenous size distribution and an even surface. Initially, the polymers used for the formulation of the nanoparticles were characterized by such methods like asymmetric flow field-flow fractionation and nuclear magnetic resonance spectroscopy. Furthermore, established measurement and calculation algorithms were revised into state-of-the-art technology and applied as so called automatic microviscosimetry for in- depth protein analysis. The development of novel nanoparticle formulations based on these polymers was done in a second step using diethyl-amino-ethanol-dextran, polysorbate and polyethylene glycol, as well as methylation and acetylation chemistry. While the modified dextran mainly increased the zeta potential of the nanoparticles, the other modifications were intended to change the pharmacokinetic distribution patterns towards e.g. prolonged circulation times. In novel nanoparticle cytology science the use of a flow chamber device for cell cultivation allowed us to study the interaction patterns of nanoparticles with adherent cells under near to physiological conditions simulating blood vessels, junctions and shear stress. This in-vitro model can be used for online preclinical and high-throughput screenings of new nanoparticle and protein formulations with cell monolayers. The hindrances in traditional static cell culture models were shown to be overcome by comparing several nanoparticle formulations in a static and in a flow model. Proper nanoparticle formulations were tested further in innovative preclinical in-vivo models like the hamster dorsal skin fold chamber and the mouse cremaster model to elucidate their body distribution and targeting properties with a focus on kinetics, blood cell interaction and novel fluorescence detection techniques. In addition, the potential of gelatin nanoparticles as therapeutic options in a model for antigen induced arthritis was demonstrated. Finally, hybrid (sandwich) nanoparticles were formulated by combining gelatin nanoparticle preformulations with the endosomolytic peptide Melittin from bee venom and loading them with small interfering RNA molecules against VEGFR2 and luciferase. The novel hybrid carriers were extensively tested in cell cultures towards their efficiency to induce a protein knock-down based on RNA interference. With these results the door for further, more profound in-vivo studies in the field of oncology might be opened

Optimized dispersion of nanoparticles for biological in vitro and in vivo studies

Background: The aim of this study was to establish and validate a practical method to disperse nanoparticles in physiological solutions for biological in vitro and in vivo studies. Results: TiO(2) (rutile) dispersions were prepared in distilled water, PBS, or RPMI 1640 cell culture medium. Different ultrasound energies, various dispersion stabilizers (human, bovine, and mouse serum albumin, Tween 80, and mouse serum), various concentrations of stabilizers, and different sequences of preparation steps were applied. The size distribution of dispersed nanoparticles was analyzed by dynamic light scattering and zeta potential was measured using phase analysis light scattering. Nanoparticle size was also verified by transmission electron microscopy. A specific ultrasound energy of 4.2 x 10(5) kJ/m(3) was sufficient to disaggregate TiO(2) (rutile) nanoparticles, whereas higher energy input did not further improve size reduction. The optimal sequence was first to sonicate the nanoparticles in water, then to add dispersion stabilizers, and finally to add buffered salt solution to the dispersion. The formation of coarse TiO(2) (rutile) agglomerates in PBS or RPMI was prevented by addition of 1.5 mg/ml of human, bovine or mouse serum albumin, or mouse serum. The required concentration of albumin to stabilize the nanoparticle dispersion depended on the concentration of the nanoparticles in the dispersion. TiO(2) (rutile) particle dispersions at a concentration lower than 0.2 mg/ml could be stabilized by the addition of 1.5 mg/ml albumin. TiO(2) (rutile) particle dispersions prepared by this method were stable for up to at least 1 week. This method was suitable for preparing dispersions without coarse agglomerates (average diameter < 290 nm) from nanosized TiO(2) (rutile), ZnO, Ag, SiO(x), SWNT, MWNT, and diesel SRM2975 particulate matter. Conclusion: The optimized dispersion method presented here appears to be effective and practicable for preparing dispersions of nanoparticles in physiological solutions without creating coarse agglomerates

Center and Periphery. Theological Perspectives on Church and Society

Krisenzeit – Zeit der Kirche – Zeit der Theologie? Die Problemlagen der Gegenwart stellen die wissenschaftliche Theologie vor so große Herausforderungen wie selten zuvor. Nicht allein stehen in den kommenden Jahren strukturelle Weichenstellungen an, welche die Kirche kaum unberührt lassen werden. Schon jetzt verlangt die prekäre Situation vieler Menschen und ganzer Völker nach einer tragfähigen Reflexion und Verkündigung des Glaubens. Christliche Theologie darf die notwendigen Antworten hier nicht schuldig bleiben. In der vorliegenden Festschrift haben sich Kollegen, Freunde und Schüler von Otmar Meuffels den vielfältigen Fragestellungen zugewandt, welche die Arbeit an der zeitgenössischen Heilsbedeutung des christlichen Glaubens aufwirft. Sie schreiben damit seinen prägenden Ansatz fort, der stets die aktuelle Relevanz der Rede von Gott im Blick hat. In diesem Sinn zeigen die in diesem Band versammelten Beiträge auf ganz unterschiedlichen Feldern die Anschlussfähigkeit der Theologie in den heute virulenten gesellschaftlichen Debatten.Time of Crisis – Times of Church – Time of Theology? Academic theology has rarely faced bigger challenges than those of the present. The coming years will see structural course changes which will leave the church hardly untouched. Even today, the precarious situation of people and people’s demands for viable reflection and proclamation of Faith. Christian theology must not fail to give necessary answers in this regard. In this publication, colleagues, friends, and students of Otmar Meuffels faced these diverse questions, which are posed by working with the contemporary soteriological significance of Christian faith. With this, they continue his defining approach which always focuses on the current relevance of the speech of God. Therefore, all contributions collected in this publication show the ability to connect theology with current and relevant societal controversies in completely different fields

Taxonomy based on science is necessary for global conservation

Peer reviewe

Role of molecular architecture and interface morphology on the performance of organic solar cells

Imperial Users onl

Role of molecular architecture and interface morphology on the performance of organic solar cells

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Optimized dispersion of nanoparticles for biological <it>in vitro </it>and <it>in vivo </it>studies

Abstract Background The aim of this study was to establish and validate a practical method to disperse nanoparticles in physiological solutions for biological in vitro and in vivo studies. Results TiO2 (rutile) dispersions were prepared in distilled water, PBS, or RPMI 1640 cell culture medium. Different ultrasound energies, various dispersion stabilizers (human, bovine, and mouse serum albumin, Tween 80, and mouse serum), various concentrations of stabilizers, and different sequences of preparation steps were applied. The size distribution of dispersed nanoparticles was analyzed by dynamic light scattering and zeta potential was measured using phase analysis light scattering. Nanoparticle size was also verified by transmission electron microscopy. A specific ultrasound energy of 4.2 × 105 kJ/m3 was sufficient to disaggregate TiO2 (rutile) nanoparticles, whereas higher energy input did not further improve size reduction. The optimal sequence was first to sonicate the nanoparticles in water, then to add dispersion stabilizers, and finally to add buffered salt solution to the dispersion. The formation of coarse TiO2 (rutile) agglomerates in PBS or RPMI was prevented by addition of 1.5 mg/ml of human, bovine or mouse serum albumin, or mouse serum. The required concentration of albumin to stabilize the nanoparticle dispersion depended on the concentration of the nanoparticles in the dispersion. TiO2 (rutile) particle dispersions at a concentration lower than 0.2 mg/ml could be stabilized by the addition of 1.5 mg/ml albumin. TiO2 (rutile) particle dispersions prepared by this method were stable for up to at least 1 week. This method was suitable for preparing dispersions without coarse agglomerates (average diameter 2 (rutile), ZnO, Ag, SiOx, SWNT, MWNT, and diesel SRM2975 particulate matter. Conclusion The optimized dispersion method presented here appears to be effective and practicable for preparing dispersions of nanoparticles in physiological solutions without creating coarse agglomerates.</p

Effect of High Sugar Intake on Glucose Transporter and Weight Regulating Hormones in Mice and Humans

<div><p>Objective</p><p>Sugar consumption has increased dramatically over the last decades in Western societies. Especially the intake of sugar-sweetened beverages seems to be a major risk for the development of obesity. Thus, we compared liquid versus solid high-sugar diets with regard to dietary intake, intestinal uptake and metabolic parameters in mice and partly in humans.</p><p>Methods</p><p>Five iso-caloric diets, enriched with liquid (in water 30% vol/vol) or solid (in diet 65% g/g) fructose or sucrose or a control diet were fed for eight weeks to C57bl/6 mice. Sugar, liquid and caloric intake, small intestinal sugar transporters (GLUT2/5) and weight regulating hormone mRNA expression, as well as hepatic fat accumulation were measured. In obese versus lean humans that underwent either bariatric surgery or small bowel resection, we analyzed small intestinal GLUT2, GLUT5, and cholecystokinin expression.</p><p>Results</p><p>In mice, the liquid high-sucrose diet caused an enhancement of total caloric intake compared to the solid high-sucrose diet and the control diet. In addition, the liquid high-sucrose diet increased expression of GLUT2, GLUT5, and cholecystokinin expression in the ileum (P<0.001). Enhanced liver triglyceride accumulation was observed in mice being fed the liquid high-sucrose or -fructose, and the solid high-sucrose diet compared to controls. In obese, GLUT2 and GLUT5 mRNA expression was enhanced in comparison to lean individuals.</p><p>Conclusions</p><p>We show that the form of sugar intake (liquid versus solid) is presumably more important than the type of sugar, with regard to feeding behavior, intestinal sugar uptake and liver fat accumulation in mice. Interestingly, in obese individuals, an intestinal sugar transporter modulation also occurred when compared to lean individuals.</p></div