Evamaria Stütz

Cell-Based Sensor System Using L6 Cells for Broad Band Continuous Pollutant Monitoring in Aquatic Environments

Pollution of drinking water sources represents a continuously emerging problem in global environmental protection. Novel techniques for real-time monitoring of water quality, capable of the detection of unanticipated toxic and bioactive substances, are urgently needed. In this study, the applicability of a cell-based sensor system using selected eukaryotic cell lines for the detection of aquatic pollutants is shown. Readout parameters of the cells were the acidification (metabolism), oxygen consumption (respiration) and impedance (morphology) of the cells. A variety of potential cytotoxic classes of substances (heavy metals, pharmaceuticals, neurotoxins, waste water) was tested with monolayers of L6 cells (rat myoblasts). The cytotoxicity or cellular effects induced by inorganic ions (Ni2+ and Cu2+) can be detected with the metabolic parameters acidification and respiration down to 0.5 mg/L, whereas the detection limit for other substances like nicotine and acetaminophen are rather high, in the range of 0.1 mg/L and 100 mg/L. In a close to application model a real waste water sample shows detectable signals, indicating the existence of cytotoxic substances. The results support the paradigm change from single substance detection to the monitoring of overall toxicity.

Using a cell-based gas biosensor for investigation of adverse effects of acetone vapors in vitro

In this study, a cell-based gas biosensor is presented used for the detection and investigation of gaseous organic compounds in air. The response of living human nasal cells (RPMI 2650) and human lung cells (A549) towards the direct exposure of gaseous substances for 10 min is monitored with a multi-parametric sensor system. Changes in the cellular impedance, oxygen consumption rate and acidification rate can be recorded after the exposure and represent the cytotoxicity of the present gas. The sensor is able to notify the presence of acetone in aqueous solution (2%) but in notably lower concentrations in the gas phase (100-333 ppm) within 30-60 min after the end of the gas exposure. Cell viability is not affected by a sequential exposure to humidified synthetic air (60% r.h.) with a flow rate of 300 ml/min and therefore offers the possibility for a continuous air monitoring. In addition, exposure to synthetic air has no influence on the signals of consecutive acetone exposure. The system might be used in the future for the monitoring of ambient air in work spaces.

Simultaneous detection of multiple bioactive pollutants using a multiparametric biochip for water quality monitoring.

Water is a renewable resource but yet finite. Its sustainable usage and the maintenance of a good quality are essential for an intact environment, human life and a stable economy. Emerging technologies aim for a continuous monitoring of water quality, overcoming periodic analytical sampling, and providing information on the current state of inshore waters in real time. So does the here presented cell-based sensor system which uses RLC-18 cells (rat liver cells) as the detection layer for the detection of water pollutants. The electrical read-out of the system, cellular metabolism, oxygen consumption and morphological integrity detects small changes in the water quality and indicates a possible physiological damage caused. A generalized functional linear model was implemented in order to regress the chemicals present in the sample on the electrical read-out. The chosen environmental pollutants to test the system were chlorpyrifos, an organophosphate pesticide, and tetrabromobisphenol A, a flame retardant. Each chemical gives a very characteristic response, but the toxicity is mitigated if both chemicals are present at once. This will focus our attention on the statistical approach which is able to discriminate between these pollutants.

3.2.3 Living cell-based gas sensor system for the detection of acetone in air

In this study, a cell-based gas biosensor is presented, which can be used for the detection of gaseous organic compounds in ambient air. The response of living human nasal cells (RPMI 2650) towards the direct exposure of gaseous substances is monitored with a multi-parametric sensor system using an exposure time of 10-15 minutes. Changes in the cellular impedance, oxygen consumption rate and acidification rate are recorded immediately after the exposure and represent the metabolic cell reaction to the gas presented. The system is able to notify the presence of acetone in aqueous solution (~2%) but also - in significantly lower concentrations - in the gas phase (~200 ppm) within 30 minutes. The concentration-dependent decrease of cellular impedance is caused by the lipophilicity of this solvent, which causes hydrophobic interactions within the protein structure of the cell. The system might be used in the future for the monitoring of ambient air in work spaces as well as for the characterization of medical gases and aerosols.