Repeated pathologies of the tympanic membrane (TM) decrease its tension inducing conductive hearing loss and adhesive processes up to cholesteatoma. Our results regarding the development of a laser based noninvasive procedure to strengthen the structure of the TM are herein presented.
Copper is a heavy metal, which is used in heat and electrical conductors and in a multitude of alloys in the technical context. Moreover, it is a trace element that is essential for the life of organisms but can cause toxic effects in elevated concentrations. Maximum limits in water and beverages exist. Here, the decrease of the fluorescence lifetime of green fluorescent protein (GFP) by Förster resonance energy transfer is used to measure the copper ion concentration in drinking water. Therefore, a system is developed that is based on a GFP sample in a predefined concentration. The GFP mutant can be excited with blue light. For binding of copper ions, a His-tag is included in the GFP. After measuring the fluorescence lifetime of pure GFP, the copper determination of the sample is performed by lifetime measurement. Therefore, the lifetime can be assigned to the copper concentration of the GFP-doped drinking water sample. In summary, a method for the quantification of copper ions based on changes of the fluorescence lifetime of GFP is developed, and the measurement of the copper concentration in water samples is performed.
Copper is a heavy metal, which is used in heat and electrical conductors and in a multitude of alloys in the technical
context. Moreover, it is a trace element that is essential for the life of organisms but can cause toxic effects in elevated
concentrations. Maximum limits in water and for beverages exist. Beyond that there is a need for the control of copper
concentrations in the fields of sewage and agriculture. Hence, competitive measurement systems that allow for the fast,
user-friendly and reliable detection are presumed to have a large potential market.
One prominent class of naturally occurring fluorophores is the Green Fluorescent Protein (GFP). GFP originally stems
from the jellyfish Aequorea Victoria and has found its way in various applications e.g. as biosensors in basic research
and for monitoring gene expression. Exploiting GFP in plant cells allowed for the visualization of the copper uptake by
changes in the GFP fluorescence. In principle changes in the fluorescence intensity or in the fluorescence lifetime can be
utilized to determine copper concentrations. However, lifetime changes have the advantage of omitting calibration
measurements and therefore make this method ideally suited for sensing purposes.
Here the decrease of the fluorescence lifetime of GFP by Förster resonance energy transfer (FRET) is used to measure
the copper ion concentration in drinking water. Therefore a system is developed that is based on a GFP sample in a
predefined concentration. The GFP mutant can be excited with blue light. For binding of copper ions a His-tag is
included in the GFP. After measuring the fluorescence lifetime of the pure GFP the copper determination of the sample
is performed by lifetime measurement. Therefore the lifetime can be assigned to the copper concentration of the GFP-doped
drinking water sample. In summary a method for the quantification of copper ions based on changes of the
fluorescence lifetime of GFP is developed and the measurement of the copper concentration in water samples is
performed.
Dye based solar cells have been studied thoroughly in recent years. However, using this technology for dye based light sensors in polymer based systems offers several advantages compared to classical devices. A printable light sensor could be easily integrated into current smart label fabrication processes. Moreover, printable light sensors combined with novel conductive polymers could solve reliability issues resulting from bonding processes. In this paper we report on the fabrication of dye based light sensors using Ruthenium 535-bis-TBA as active dye and Iodide solution as charge transporting layer. A prototype has been developed and tested successfully. In order to improve the technology towards smart label integration, silica gel has been used to harden the Iodide liquid electrolyte. Depending on the silica gel concentrations, different stiffness levels can be achieved. Whereas the first light sensor prototypes have been made on glass substrates, the new ones are based on polymer substrates. The polymer foil KAPTON by Du Pont has been used as substrate. Special care has to be taken regarding the preparation of the transparent electrodes. The transparent conductive oxide (TCO) Indium Tin Oxide (ITO), which has been used as transparent electrode, has to be cured at elevated temperatures.
In conclusion we have shown that dye based light sensors can be used for the integration into smart labels. Moreover modifications in the process lead to a light sensor which is compatible to future polymer based systems.
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