Irritable bowel syndrome (IBS) is a disease affecting up to 15% of the population in the developed world. Symptoms such as abdominal pain, diarrhea, constipation and psychological problems negatively affect the patient’s life leading to an economical burden on society due to an increased absence from work and costs related to medical care. The exact cause of IBS is still up for debate but over the years it has become clear that an elevated histamine concentration in the gastrointestinal (GI) tract can be both an indicator and cause of IBS . The current state of detection requires extraction of gastrointestinal fluids by means of endoscopy and biopsy of the GI tract to exclude certain other diseases. Currently the histamine concentration can be measured by relatively expensive techniques such as high pressure liquid chromatography (HPLC). An alternative method of detection utilizes molecularly imprinted polymers (MIPs) which are biomimetic receptor elements that can be produced at low cost and offer superior resistance to detoriation by heat, pH and time. In the past these MIPs have been used in combination with electrochemical impedance spectroscopy and the heat-transfer method (HTM) to detect histamine, serotonin and nicotine in biological fluids [2-3]. These detection methods rely on the fact that water filled cavities in the MIPs show a lower thermal- and electrical resistance than cavities that are filled with bound target molecules.
In our research we are working towards integration of a MIP based biosensor into a catheter such as the ones that are already used inside hospital settings and in parallel work is done on an external measurement cell for in vitro reference measurements. The intestinal, catheter based measurement, will allow for more accurate histamine measurements because the patient experiences less stress compared to a fullscale endoscopy. Along with more patient comfort an on-site measurement does not suffer from sample detoriation due to ambient oxygen which is hard to avoid in the time gap between extraction and analysis in a hospital lab. The external measurement cell can be connected to currently existing GI fluid-aspiration catheters in order to measure the histamine concentration simultaneously right next to the patient during extraction. Impedance spectroscopy is the proposed read-out method since this is already commonly performed on patients for medical purposes. Acknowledgements: FWO project G.0B25.14N. Monitoring of gut functions and inflammation processes with biomimetic sensors based on molecularly imprinted polymers.
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