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Cell or living tissues are cultured in microreaction chambers. Cell metabolic rates are monitored in real time with electric or optic microsensors for pH value and dissolved oxygen operating within these chambers. One of the most important application areas is the improvement of cancer treatment by in-vitro analyzing the individual chemosensitivity profiles prior to the application of chemotherapy. However, in a clinical setting any in-vitro diagnostic approach requires strict measures of data quality control. In order to identify operational faults in sensor readings, the signals were simulated in a 3-D finite element model (FEM) of diffusion. The program chosen was COMSOL. The model is not only used for the filtering of false data but also for the analysis of material effects (e.g. gas diffusion and absorption through polymers), for optimising the microchamber geometry and for investigating the kinetics of cell metabolism within different distributions of cell densities. [ABSTRACT FROM AUTHOR]

Impedance sensors in thick film technology have been designed as a tool for electric cell impedance sensing. The screen printed gold electrodes and the flexible PET polymeric chip substrate are homogeneously grown with Hela cells as documented by fluorescence microscopy. In contrast to previously published cell impedance measurements, we discuss the use of revised experimental conditions to improve the accuracy of the measurements. Responses of confluent cell monolayers to the treatment with two bioactive compounds are tested: (1) Histamine, triggering a cell morphological reaction and (2) the non-ionic detergent Triton X-100, leading to a complete disruption of cell membranes. The impedance is measured and compared with a standard, planar electrode arrangement for statistical evaluation. [ABSTRACT FROM AUTHOR]

In pharmacologic drug-screening and medical diagnostics, a trend towards the utilization of functional assays using living cells can be observed. Cellular life is determined by dynamic and networked molecular processes. These processes can be investigated by measuring several extra cellular parameters. This paper describes a high-throughput system that delivers real-time monitoring data of cell parameters (metabolic and morphological alterations), e.g. upon treatment with drug compounds. A life-maintenance system keeps important environmental parameters (gas, humidity, sterility, temperature) constant. [ABSTRACT FROM AUTHOR]

Application fields of microsensors are shown and the potential of the O2-FET in this field is described. The principle of measurement of pH with the O2-FET is described and an extension towards a parallel measurement of dissolved oxygen via amperometric and potentiometric methods is presented. Furthermore a finite elements model which describes the transactions at the O2-FET is introduced. Results of real measurements and of the simulation are presented and discussed. [ABSTRACT FROM AUTHOR]