Biomedical subjects

Helmut Grothe

Publications and source records attributed to Helmut Grothe.

3 recordsLinked to original sources

PubMed2006

Electric cell-substrate impedance sensing with screen printed electrode structures.

Impedance sensors in thick film technology have been tested as a tool for electric cell-substrate impedance sensing. The screen printed Pt electrodes have a width of 250-400 microm. Electrodes and the surrounding ceramic chip substrate could be homogeneously grown with L-929 and Hela cells. The performance of a screen printed interdigitated electrode structure (IDES) was compared with that of thin film structures with the same layout geometry. The thick film impedance sensors allowed to correctly record the morphological response of confluent Hela cell layers to stimulation with histamine. A thick film conductivity sensor also revealed impedance values which were dependent on cell growth on the electrode surface, even at a very low frequency range of approximately 1 Hz.

Animals↗

PubMed2004

[Chips instead of mice: cells on bioelectronic sensor-chips as an alternative to animal experiments].

An alternative assay for replacing animal experiments should serve the specific microphysiological needs of the cells and be endowed with multiparametric signal monitoring. These requirements are provided by a test system in which the key elements are biocompatible electronic sensor-chips. It is also connected to a medium perfusion set-up, which allows to control the supply of nutrients and test compounds, and the removal of culture medium. The chips are equipped with sensors that continuously monitor basic metabolic parameters and membrane-associated changes of living cells: pH-ISFETs for extracellular acidification, amperometric O2-sensors for oxygen consumption, and IDES for electrical impedance of the cell layer. Experiments with LS174T colon carcinoma cells in culture show the metabolic and electrical changes upon incubation with Zytochalasin B and chloroacetaldehyde. The signal patterns vary and indicate different mechanisms of action for these test compounds. With this test system it is possible to detect effects of unknown substances and mixtures, and to analyse the cellular probe for prolonged times.

Animal Testing Alternatives↗

PubMed2003

Multiparametric sensor chips for chemosensitivity testing of sensitive and resistant tumor cells.

Many different assays have been developed for testing the chemosensitivity of tumor cells in vitro, usually based on a single biochemical or cellular parameter. A multiparametric test system has been developed that accommodates on a single chip numerous sensors for metabolic parameters, deltapH and deltapO2, as well as for morphological changes. The cells grow directly on the chips and can be continuously monitored online up to several days. The effects of various chemotherapeutic drugs on the metabolic profile of several tumor cell lines have been investigated. In colon carcinoma-derived LS174T cells, cytochalasin B markedly increased oxygen consumption while decreasing the rate of extracellular acidification. These effects, which reflect the biochemical action of cytochalasin B, were reversible on drug removal. In contrast, chloroacetaldehyde markedly reduced respiration, which recovered when the drug was removed. Primary breast cancer cells also responded to chloroacetaldehyde with a marked reduction in deltapO2, followed by a reduced rate of acidification. Comparing the metabolism of doxorubicin-sensitive and -resistant mouse sarcoma S180 cells, the rates of acidification and respiration were inhibited by doxorubicin only in the sensitive cells, whereas in the resistant cells oxygen consumption even increased. These examples demonstrate that this chip-based test system provides rapid and important information for assessing chemosensitivity of tumor cells.

Acetaldehyde↗