"Development and study of diamond architectures for biosensing applications."
The irritable bowel syndrome is a condition in which the normal muscular function of the gut is disrupted. This disturbance brings large loads with it, affecting everyday life such that the quality of life of the patients is deteriorated. About 20% of the population suffers from this disease.The research is driven from the perspective of the patient welfare and the economic implications of this disease. The pathogenesis of this disorder is not known but it is thought that the mast cell degranulation, which among other things, histamine and tryptase are freely put, may be a possible mediator for this condition. Current techniques do not allow to measure concentrations of these substances on the spot. Therefore, there has been attempted to develop a rapid test, that allows measurements in vivo so that the short live mast cell degranulation can be followed on the mucous membrane of the small intestine.
The biosensor which is being developed for the detection of histamine is a polymer-based immunogen, which is read out impedimetrically.
The biological recognition layer consists of antibodies against histamine which are physically adsorbed to the transducer layer, for which in this project a semi-conductive polymer MDMO-PPV is used . With contact angle measurements, the saturation concentration of this surface functionalizationis has been determined. This functionalization is confirmed by several characterization techniques such as Quartz Crystal Microbalance (QCM) and Atomic Force Microscopy (AFM). Due to its low molecular weight (111 Da) histamine is difficult to detect impedimetrically. This project uses interdigital electrodes (IDE) to significantly increase the sensitivity. In this way the impedimetric signal changed 30% when detecting 120nmol / ml histamine. Also a synthesis of a competitor of a competing assay is tested.