Microfluidic biosensor systems for cardiotoxicity assaying

Sammanfattning: Toxicity screening is an important part of pharmaceutical development and early detection of toxic side effects provide the opportunity for early redesign or termination of unfeasible projects. Today toxicity testing is relying on experiments on animals. Ethical concerns, high costs and problems with interspecies variability in animal experiments have introduced incentives for cell-based toxicity assays. The recent development of stem cell technology have raised the hope for toxicity testing with higher predictivity that can reduce the amount of animals sacrificed, increase the patient safety and reduce the costs in pharmaceutical development.Cell development and behavior is to a large extent dependent on the microenvironment. Microfluidic techniques can be used to build small-sized structures that provide the opportunity to introduce a high degree of control of the cell culture environment with features in cell sizes. In this thesis is demonstrated two different methods for infusing cells into microfluidic cell culture devices using either cells clustered in cardiac bodies during differentiation or cells pre-seeded in microporous carriers prior to infusion.Microfluidic cell culture devices are well suited for optical  evaluation. Demonstrated in this thesis is fluorescent staining in combination with confocal microscopy as well as automated imaging with evaluation of beating frequency of cardiomyocyte cell clusters can be used to assess toxicity of cells cultured in microfluidic devices.Biosensors use biological recognition elements to measure the presence of a chemical substance, for example low concentrations of biomarkers secreted by cells in a toxicity assay. Especially capacitive biosensors have shown very low limit of detection. In addition, protein G is demonstrated as an affinity ligand to capture IgG antibodies used as recognition element in a biosensor application or used for antibody screening.