Monitoring Cells and Spores by Biomimetic Sensors - Applications in Biotechnology and Biological Threat

摘要

Biological species such as cells are permanently changing their properties due to environmental conditions and nutrition. An innovative recognition strategy is based on patterning polymers with bioparticles of interest. Thus, cavities are generated which engulf e.g. cells and spores. An efficient enrichment of analytes on the surface of these coatings can be detected by QCMs (Quartz-Crystal- Microbalances). The mass-sensitive QCM data were compared with AFM (Atomic-Force-Microscopy) measurements, where e.g. Escherichia coli bacteria adhered on a sensor coating were directly counted. Furthermore, the conversion of spores to bacteria can be monitored when sufficient nutrition is guaranteed. This process was studied via B. subtilis spores / bacteria as model for anthrax threat. Both the decay of spores and the growth of bacteria can be monitored by a Sauerbrey effect via a frequency alteration. The bacteria are selectively incorporated into the sensor layer which consists of a cross linked polyurethane. A glucose concentration of 10% in solution yields saturation effects concerning the influence of nutrition. Furthermore, progress was achieved in detecting cells by patterning with plastic cells which were generated by double imprinting by native analogues. Thus, sensor coatings can be reproduced easily. Synchronized cells can be used for selective monitoring of cells at a distinct growing phase. Thus, the type of cells, e.g. the bacterium strain, stages of cell reduplication and extent of nutrition can be recognized by biomimetic sensor strategies.