Sensor System for Autonomous Detection of Mold Spore Contamination

An autonomous sensor system for monitoring mold spore contaminations inside archives at desired time intervals is presented. Presence of airborne mold spores in the indoor environment not only damages organic material but it is also a potential threat to human health. To avoid this risk a sensor system for monitoring mold spore concentrations is of great importance. In this thesis, a mold sensor system with a replaceable bioreactor array for autonomous detection of the airborne spores has been investigated. The sensor system consists of a bioreactor cartridge to analyze the mold growth, an air sampling unit for distributing the mold spores into the bioreactors and a control unit to automatize the detection process. Each bioreactor is sealed with a sacrificial silicon nitride membrane, which can be opened on demand. Once activated, the membrane gets opened and the spores present in the air sample get in contact with the culture medium and start to germinate. The mold detection is performed by using an integrated approach of impedance and colorimetric principles

Sensorsystem zur autonomen Erkennung von Schimmelpilzkontaminationen

An autonomous sensor system for monitoring mold spore contaminations inside archives at desired time intervals is presented. Presence of airborne mold spores in the indoor environment not only damages organic material but it is also a potential threat to human health. To avoid this risk a sensor system for monitoring mold spore concentrations is of great importance. In this thesis, a mold sensor system with a replaceable bioreactor array for autonomous detection of the airborne spores has been investigated. The sensor system consists of a bioreactor cartridge to analyze the mold growth, an air sampling unit for distributing the mold spores into the bioreactors and a control unit to automatize the detection process. Each bioreactor is sealed with a sacrificial silicon nitride membrane, which can be opened on demand. Once activated, the membrane gets opened and the spores present in the air sample get in contact with the culture medium and start to germinate. The mold detection is performed by using an integrated approach of impedance and colorimetric principles

An Impedance-Based Mold Sensor with on-Chip Optical Reference

A new miniaturized sensor system with an internal optical reference for the detection of mold growth is presented. The sensor chip comprises a reaction chamber provided with a culture medium that promotes the growth of mold species from mold spores. The mold detection is performed by measuring impedance changes with integrated electrodes fabricated inside the reaction chamber. The impedance change in the culture medium is caused by shifts in the pH (i.e., from 5.5 to 8) as the mold grows. In order to determine the absolute pH value without the need for calibration, a methyl red indicator dye has been added to the culture medium. It changes the color of the medium as the pH passes specific values. This colorimetric principle now acts as a reference measurement. It also allows the sensitivity of the impedance sensor to be established in terms of impedance change per pH unit. Major mold species that are involved in the contamination of food, paper and indoor environments, like Fusarium oxysporum, Fusarium incarnatum, Eurotium amstelodami, Aspergillus penicillioides and Aspergillus restrictus, have been successfully analyzed on-chip