For the first time, the covalent immobilization of oligonucleotides double helices onto surfaces prior to sequential denaturation and rehybridization is proven to lead to optimal hybridization efficiency. Two indirect methods were used for monitoring these reactions in situ: the quartz crystal microbalance with dissipation monitoring (QCM-D) and the wavelength interrogated optical sensor (WIOS, Bright Reader). Both techniques led to the result that with this immobilization approach one could reach nearly 100% hybridization efficiency. Moreover, applying the polymer theory to the adsorption of nucleotide sequences onto surfaces, we demonstrate, that for single stranded sequences the coil conformation prevails over the stretch one.
This chapter reviews the use of dynamic light scattering (DLS) in the wide field of supramolecular materials chemistry through nonexhaustive yet representative examples. Aside from demonstrating the broad field of applicability of DLS, the basic principle of light scattering with reference to excellent publications on the theoretical background is recalled to highlight the major limitations of the technique to prevent misuse.
Neopterin is synthesized by human monocyte-derived macrophages primarily upon stimulation with the cytokine interferon-Q Q. We studied the in£uence of neopterin on the generation of reactive oxygen species (ROS) in human peripheral blood neutrophils. Radical formation was measured using a biochemiluminometer. Neutrophils were isolated from peripheral blood of healthy donors. The generation of ROS by neutrophils suspended in Earl's solution (pH = 7.4) at 37 ‡C was investigated by monitoring of chemiluminescence using luminol and lucigenin as light emitters. Neopterin induced chemiluminescence in suspensions of neutrophils in the presence of luminol, but not of lucigenin. Neopterin a¡ected only adhesive cells. Addition of neopterin into the suspension of the cells involving D-mannitol, L-histidine and diazabicyclo[2.2.2]octane (DABCO) decreased luminol-dependent chemiluminescence (LDCL) of the neutrophils. The action of superoxide dismutase (SOD) and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) reduced neopterin-induced LDCL of neutrophils. Data suggest that neutrophils respond on exposure to neopterin with additional generation of singlet oxygen, hydroxyl radical and nitric oxide by nicotinamide adenine dinucleotide phosphate (NADPH)-independent pathways. ß
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