The use of multiple-strain algal sensor chips for the detection and identification of volatile organic compounds

Although biosensors detecting a great variety of toxicants have been developed during the last decades, the simultaneous detection and identification of several targets by one biosensor is not possible in the majority of the biosensor systems. In our study we proved the concept of the detection and identification of two different volatile toxic compounds with a non-selective biochip-based algal biosensor. For that purpose we produced array plate biochips to utilise three membrane-immobilised algal strains of genus Klebsormidium and Chlorella in one biosensor system. A novel IMAGING-PAM chlorophyll fluorometer was applied to measure the impact of volatile organic compounds (VOC) on photosynthesis of chip-immobilized algae in terms of quantum efficiency of electron transport (DeltaF/F'm). Formaldehyde (FA) vapour was detectable with statistical significance in concentrations relevant to human health from 10 ppb to 10 ppm. The biosensor response recorded within minutes was concentration-dependent and reversible. Moreover, vapours of formaldehyde (0.05-1 ppm) and methanol (MeOH) (200-1000 ppm) were significantly identified by the compound-specific response rate as a quotient of the biosensor responses of the respective algal strains. Using the IMAGING-PAM chlorophyll fluorometer, data sampling proved to be highly efficient. Based on our results we conclude that the principle of the algal sensor chip (ASC) suggests further research on the detection and identification of VOCs and other toxic substances in gaseous environment with that biochip system.