Within this seminar, I will introduce electrochemical impedance spectroscopy (EIS) as a versatile, label free biosensing technique, which allows the monitoring of bio-molecular recognition events in real time. EIS operates fast, it is easy to integrate with microelectronics, and it is most promising for medical point-of-care applications. EIS has only very few pitfalls (usually solvable by 'common sense' and refined modeling) while the application range is remarkably broad. I will illustrate this by examples from two different life-science fields: Genomics: The detection and identification of single-nucleotide polymorphisms (SNPs) in DNA is a key towards the understanding of several hundreds of inherited diseases. Alzheimer's disease is one of these. The detection of SNP's is usually based on thermal melting of DNA-duplexes with readout by light scattering. Chemical denaturation of DNA by diluted NaOH is substantially faster, it takes only a few minutes, and EIS allows precisely to distinguish whether SNPs are present or not. Food safety: Many small molecules (toxins, neurotransmitters etc.) are hard to detect due to the lack of corresponding antibodies or enzymes. Molecularly imprinted polymers (MIPs) are therefore an interesting type of synthetic receptors, which are able to bind these target molecules in a specific way. This biomimetic recognition alters the dielectric properties at the surface of MIP-modified electrodes and this can in turn be monitored by EIS. The combination of EIS with MIP receptors allows detecting e.g. nicotine, histamine, malachite green, and serotonin at nanomolar concentrations in biologically relevant matrices. Acknowledgements: this work is supported by UHasselt-BOF, the Life-Science Initiative of the Province of Limburg, the Research Foundation Flanders FWO, the Belgian Federal Science Policy Office BELSPO, and the European Framework Program FP 7.
Within this seminar, I will introduce electrochemical impedance spectroscopy (EIS) as a versatile, label free biosensing technique, which allows the monitoring of bio-molecular recognition events in real time. EIS operates fast, it is easy to integrate with microelectronics, and it is most promising for medical point-of-care applications. EIS has only very few pitfalls (usually solvable by 'common sense' and refined modeling) while the application range is remarkably broad. I will illustrate this by examples from two different life-science fields: Genomics: The detection and identification of single-nucleotide polymorphisms (SNPs) in DNA is a key towards the understanding of several hundreds of inherited diseases. Alzheimer's disease is one of these. The detection of SNP's is usually based on thermal melting of DNA-duplexes with readout by light scattering. Chemical denaturation of DNA by diluted NaOH is substantially faster, it takes only a few minutes, and EIS allows precisely to distinguish whether SNPs are present or not. Food safety: Many small molecules (toxins, neurotransmitters etc.) are hard to detect due to the lack of corresponding antibodies or enzymes. Molecularly imprinted polymers (MIPs) are therefore an interesting type of synthetic receptors, which are able to bind these target molecules in a specific way. This biomimetic recognition alters the dielectric properties at the surface of MIP-modified electrodes and this can in turn be monitored by EIS. The combination of EIS with MIP receptors allows detecting e.g. nicotine, histamine, malachite green, and serotonin at nanomolar concentrations in biologically relevant matrices. Acknowledgements: this work is supported by UHasselt-BOF, the Life-Science Initiative of the Province of Limburg, the Research Foundation Flanders FWO, the Belgian Federal Science Policy Office BELSPO, and the European Framework Program FP 7.
