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- Silica (2) (entfernen)
The implementation of fluorescent methods is of outstanding importance in the field of optical chemical sensor Technology and biosciences. Their bioanalytical applications are manifold including fluorescence microscopy, fluorescence in situ hybridization, DNA sequencing, fluorescence-activated cell sorting, immunoassays, analysis of DNA and Protein microarrays, and quantitative PCR, just to name a few examples. Particularly, fluorescence microscopy is a valuable method in the versatile field of biomedical imaging methods which nowadays utilizes different fluorescence Parameters like emission wavelength/Color and lifetime for the discrimination between different targets. Sectional Images are available with confocal microscopes. Tissue, cells or single cellular compartments can be stained and visualized with fluorescent dyes and biomolecules can be selectively labeled with fluorescent dyes to Monitor biomolecular interactions inside cells or at Membrane bound receptors.
On the other hand , fluorophores can act as indicator (or "molecular probe") to visualize intrinsically colorless and non-fluorescent ionic and neutral analytes such as pH, Oxygen (pO2), metal ions, anions, hydrogen peroxide or bioactive small organic molecules such as Sugars or nucleotides. Thereby, their photoluminescent properties (fluorescence or phoporescence intensity, exitation and/or Emission wavelength, emission lifetime or anisotropy) respond to the presence of these species in their immediate Environment. In general, the use of luminescent probes has the advantage that they can be delivered directly into the sample, and detected in a contactless remote mode. By now, these probes are often encapsulated in different types of nanoparticles (NPs) made from (biodegradable) organic polymers, biopolymers or inorganic materials like silica or bound to their surface.
Sol-Gel wood preservation
(2017)
The sol–gel-based modification of wood introduces chemical substances into wood in order to improve its characteristics and impart new properties. It stabilizes dimensions of wood (timber) components, increases its strength and resistance to water, and reduces cracking. Many sol–gel-based impregnations aim to protect against wood rot and fire. In most cases, the treatments are performed with alkoxysilanes, polysiloxanes, colloidal silica, or organically modified silica. In addition further substances such as titania, copper, and boron compounds have been applied on different types of wood. The precursor solutions were introduced by immersion, painting, or spray coating of wood followed by a drying and heat treatment process. The structure of the impregnated wood was investigated by SEM, EDX, TEM, FT-IR, NMR, and XRD. Frequently, test procedures according to standards were applied in order to assess the improvement in properties. Investigations demonstrate that silica and titania impregnations change properties first of all with increasing the amount of absorbed inorganic material (WPG), which is determined by the concentration of precursors, amount and size of particles in the sol, and the impregnation method. Sol–gel impregnation can be considered as an environmentally friendly approach of wood preservation. Various improvements in wood properties can be achieved such as reduced water uptake and volume swelling, improved weather stability, resistance against biodegradation, and fire retardancy.