An electrochemical microfluidic sensor system with 96 measurement channels for quantitative characterization of biofilm formation from multi-resistant bacterial mixed populations and for the development of strategies for their inactivation and destabilization

• Applicants: Professor Dr.-Ing. Bastian Ernst Rapp; Professor Dr. Thomas Schwartz
• Subject Area: Microsystems ; Measurement Systems ; Parasitology and Biology of Tropical Infectious Disease Pathogens
• Term: from 2012 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 224685959

Biofouling can be observed on any technical substrate in direct contact with aqueous systems. Over time, so-called biofilms will form on these substrates. Biofilms are sessile colonies of bacteria that form tissue-like structures. The bacteria organized in biofilms are substantially more resistive compared to bacteria in suspension and are genetically very adaptive. This capability leads to a fast and efficient adaption to environmental conditions which renders formerly effective treatment and removal strategies ineffective over very short time spans. The increase of these antibiotic-resistant germs in hospitals has become alarming. The World Health Organization has deemed this one of the most critical hazards for human health of the upcoming decades. In order to develop and characterize new and effective treatment strategies against these bacteria, new technological and microbiological tools for fast, parallel and quantitative assessment of biofilm formation and for quantitative characterization of treatment strategies are urgently required.Here the current proposal will make a substantial contribution. In the course of this projects second funding phase, a multi-channel sensor system which was developed during the first funding phase will be used for the characterization of single species and mixed species biofilms formed from antibiotic-resistant bacteria. The system allows parallel and time-resolved characterization of biofilm formation using electrochemical impedance spectroscopy (EIS) on a total of 96 measurement channels in 48 microfluidic channels at a time. Besides EIS the system allows monitoring the activity of the formed biofilms using amperometry which allows the quantitative characterization of the effectiveness of treatment strategies to remove and/or inactive the biofilms. During this project, the sensor system will be expanded and further sensor capability will be added. The amperometric measurement will be expanded to a total of 96 measurement channels. In addition, online measurement of oxygen and of the biofilms optical density will be added. Furthermore, online removal of samples from the biofilms formed in the microfluidic channels will be implemented in order to assess the biofilms transcriptome. Using this system, two application scenarios will be addressed. First, the characterization of treatment and cleaning strategies on biofilms formed from multi-resistant mixed populations in order to develop more effective protocols for biofilm removal and/or inactivation and to elucidate the underlying mechanisms of genetic adaptation. Second, the system will be used for online monitoring and genetic profiling of the induced development of antibiotic resistance. This will allow unmatched insight into the mechanisms of resistance formation while providing a system which allows characterization and optimization of potential treatment strategies on multi-resistant bacteria strains in a quantitative, time-resolved manner.

• DFG Programme: Research Grants