Medicine is constantly developing and in order to (early) diagnose common diseases, such as cancer, Parkinson's or Alzheimer's, a liquid biopsy-based approach is of increasing relevance. Samples are complex body fluids, especially blood, whereby a separation of the cells, particles and molecules of interest is often necessary for a subsequent analysis. Conventional methods such as centrifugation, the gold standard of many sample preparations, are reaching their limits in terms of gentle cell separation, purity and automatability. At the same time, the volumes of biological samples required for analysis are decreasing and point-of-care solutions are becoming increasingly important. New technologies for sample preparation are therefore urgently needed to meet this demand. Surface acoustic wave (SAW)-based microfluidic systems have already shown promising results in the handling of biological samples, but there is still a lack in the ability to transfer laboratory set-ups into a real-world environment. In this work, an industrially feasible manufacturing technology for SAW-based microfluidic chips that can be used for separation of blood plasma was developed. For this purpose, polymeric microchannels were integrated directly on the piezoelectric substrate together with the interdigital transducers required for SAW excitation. This was done reproducibly on the wafer-level with established lithographic methods, but a relatively young material system, i.e. dry film resists, allowing an industrial scale-up of the acoustofluidic chips. Furthermore, the chip layout was designed robustly to ensure a stable and continuous separation process and the “lab-around-the-chip” was further developed into an easy-to-use system. Moreover, blood plasma separation at high flow rates of up to 50 μL/min for a 1:5 diluted sample and a throughput of 888,000 cells/s in the SAW-based microfluidic chip was demonstrated. In comparison to microfluidic alternatives, high cell separation purity was achieved with special focus on the use of analytical methods for the detection of low cell concentrations in blood plasma. Direct comparison to centrifugation further indicated a gentler separation method for the cells and more reproducible results. The SAW-based microfluidic system developed in this work offers great potential for future application in liquid biopsy.

Reliable analytical tools are important for time efficient and economical process development, production and batch release of pharmaceuticals. Therapeutics recovered from human plasma, called plasma protein products, involve a large pharmaceutical industry of plasma fractionation. In plasma fractionation of human immunoglobulin G (hIgG) and albumin (HSA) recommended analysis techniques are regulated by the European Pharmacopoeia and are including total protein concentration assays and zone electrophoresis for protein composition and purity. These techniques are robust, but more efficient techniques with higher resolution, specificity and less hands-on time are available. Surface plasmon resonance is an optical method to study biomolecular interactions label-free in real time. This technology was used in this master thesis to set up assays using Biacore systems for quantification of HSA and hIgG from all steps of chromatographic plasma fractionation as a tool for process development and in-process control. The analyses have simplified mass balance calculations to a high extent as they imply specific detection of the proteins compared with using total protein detection. The assays have a low hands-on time and are very simple to perform and the use of one master calibration curve during a full week decreases analysis time to a minimum. Quick, in-process control quantification of one sample is easily obtained within <10 minutes. For final QC of hIgG or for process development, an assay to quantify the distribution of the IgG subclasses (1-4) was set up on Biacore and showed significantly lower hands-on time compared with a commercial ELISA. All assays showed reliable quantification and identification performed in unattended runs with high precision, accuracy and sensitivity.