Biological applications of magnetic nanoparticles

In this review an overview about biological applications of magnetic colloidal nanoparticles will be given, which comprises their synthesis, characterization, and in vitro and in vivo applications. The potential future role of magnetic nanoparticles compared to other functional nanoparticles will be discussed by highlighting the possibility of integration with other nanostructures and with existing biotechnology as well as by pointing out the specific properties of magnetic colloids. Current limitations in the fabrication process and issues related with the outcome of the particles in the body will be also pointed out in order to address the remaining challenges for an extended application of magnetic nanoparticles in medicine.

Direct metabolites of Ethanol as biological markers of alcohol use: Basic aspects and applications

In addition to self reports and questionnaires, biomarkers are of relevance in the diagnosis of and therapy for alcohol use disorders. Traditional biomarkers such as gamma-glutamyl transpeptidase or mean corpuscular volume are indirect biomarkers and are subject to the influence of age, gender and non-alcohol related diseases, among others. Direct metabolites of ethanol such as Ethyl glucuronide (EtG), ethyl sulphate (EtS) and phosphatidylethanol (PEth) are direct metabolites of ethanol, that are positive after intake of ethyl alcohol. They represent useful diagnostic tools for identifying alcohol use even more accurately than traditional biomarkers. Each of these drinking indicators remains positive in serum and urine for a characteristic time spectrum after the cessation of ethanol intake - EtG and EtS in urine up to 7 days, EtG in hair for months after ethanol has left the body. Applications include clinical routine use, emergency room settings, proof of abstinence in alcohol rehabilitation programmes, driving under influence offenders, workplace testing, assessment of alcohol intake in the context of liver transplantation and foetal alcohol syndrome. Due to their properties, they open up new perspectives for prevention, interdisciplinary cooperation, diagnosis of and therapy for alcohol-related problems.

The Influence of Different Metal-Chelators on the Biological Profil of Nanoparticles for Gallium-68 Based Molecular Imaging

The use of metal chelators is becoming increasingly important in the development of new tracers for molecular imaging. With the rise of the field of nanotechnology, the fusion of both technologies has shown great potential for clinical applications. The pharmacokinetcs of nanoparticles can be monitored via positron emission tomography (PET) after surface modification and radiolabeling with positron emitting radionuclides. Different metal ion chelators can be used to facilitate labeling of the radionuclides and as a prerequisite, optimized radiolabeling procedure is necessary to prevent nanoparticle aggregation and degradation. However, the effects of chelator modification on nanoparticle pharmacokinetic properties have not been well studied and currently no studies to date have compared the biological effects of the use of different chelators in the surface modification of nanoparticles.

Sugar modification as a means to increase the biological performance of oligonucleotides

Modification of the ribose unit in DNA and RNA profoundly influences the self-rcognition and the biological properties of the nucleic acids. Conformational restriction of the ribose units, as in LNA and tricyclo-DNA, has been identified as a powerful tool to increase DNA and RNA affinity as well as biological stability and antisense properties. Apart from that sugar modified DNA analogues, as homo-DNA, have shown to be orthogonal base-pairing systems which by virtue of non-crosscommunicating with the natural nucleic acids open novel applications in biotechnology.

Strategies to determine the biological function of microRNAs

MicroRNAs (miRNAs) are regulators of gene expression that control many biological processes in development, differentiation, growth and metabolism. Their expression levels, small size, abundance of repetitive copies in the genome and mode of action pose unique challenges in studies elucidating the function of miRNAs. New technologies for identification, expression profiling and target gene validation, as well as manipulation of miRNA expression in vivo, will facilitate the study of their contribution to biological processes and disease. Such information will be crucial to exploit the emerging knowledge of miRNAs for the development of new human therapeutic applications.

Influence of polymers on microstructure and adhesive strength of cementitious tile adhesive mortars

The impact of polymer modification on the physical properties of cementitious mortars is investigated using a multimethod approach. Special emphasis is put on the identification and quantification of different polymer components within the cementitious matrix. With respect to thin-bed applications, particularly tile adhesives, the spatial distributions of latex, cellulose ether (CE), polyvinyl alcohol (PVA), and cement hydration products can be quantified. It is shown that capillary forces and evaporation induce water fluxes in the interconnected part of the pore system, which transport CE, PVA, and cement ions to the mortar interfaces. In contrast, the distribution of latex remains homogeneous. In combination with results from qualitative experiments, the quantitative findings allow reconstruction of the evolution from fresh to hardened mortar, including polymer film formation, cement hydration, and water migration. The resulting microstructure and the failure modes can be correlated with the final adhesive strength of the tile adhesive. The results demonstrate that skinning prior to tile inlaying can strongly reduce wetting properties of the fresh mortar and lower final adhesive strength.