Christin Fischer

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Aerobic spores pose serious problems for both food product manufacturers and consumers. Milk is particularly at risk and thus an important issue of preventive consumer protection and quality assurance. The spore-former Bacillus cereus is a food poisoning Gram-positive pathogen which mainly produces two different types of toxins, the diarrhea inducing and(More)
A semiautomated two-step method for in vitro selection of DNA aptamers using magnetic separation and solid-phase emulsion polymerase chain reaction has been developed. The application of a magnetic separator allows the simultaneous processing of up to 12 SELEXs (systematic evolution of ligands by exponential enrichment) with different targets or buffer(More)
The quality of the beverage industry's products has to be constantly monitored to fulfill consumers' high expectations. The thermo-acidophilic Gram-positive Alicyclobacillus spp. are not pathogenic, but their heat-resistant endospores can survive juice-processing conditions and have become a major economic concern for the fruit juice industry. Current(More)
Usually, small molecules like single metabolites used in clinical diagnostic can be quantified by instrumental approaches like LC-MS or bioanalytical techniques using antibodies or aptamers as selective receptors. The present work comprises the generation of aptamers with an affinity towards the medically relevant metabolite phytosphingosine via the(More)
Marzipan is a confectionary which is mostly offered in form of filled chocolate, pralines, or pure. According to the German guidelines for oil seeds only almonds, sugar and water are admitted ingredients of marzipan. A product very similar in taste is persipan which is used in the confectionary industry because of its stronger flavor. For persipan(More)
The present work demonstrates the first automated enrichment approach for antibiotics in milk using specific DNA aptamers. First, aptamers toward the antibiotic sulfanilamide were selected and characterized regarding their dissociation constants and specificity toward relevant antibiotics via fluorescence assay and LC-MS/MS detection. The performed(More)
The present work demonstrates the implementation of aptamers as capture molecules for a wide range of target classes in lateral flow assay applications. The targets were chosen in order to cover a wide range of target classes (small sized - metabolite, medium sized - protein, and large sized - whole cell/spore). For each target class one target molecule was(More)
Aptamer-based trapping techniques are in general suitable to replace common antibody-based enrichment approaches. A time-consuming isolation or clean-up is often necessary during sample preparation, e.g. for the detection of spores. For the development of bioanalytical routine approaches, aptamers with a high affinity to B. cereus spores were applied for(More)
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