Semen Refinement: Microfluidic separation techniques for the removal of micro-organisms from semen for the veterinary industry

In the veterinary industry, artificial insemination is widely applied to produce offspring. Although the spread of diseases is minimized by artificial insemination, micro-organisms are still found in semen. Apart from spreading diseases to recipient female, the presence of micro-organisms in semen decreases semen quality and therewith fertilization rates are reduced. Currently, antibiotics are applied to every semen dose to kill bacteria and screening techniques are performed frequently to detect viruses in semen. However, these processes have several disadvantages such as the emergence of antibiotic resistant bacteria as well as the time duration and working hours before a test results is known. The aim of the doctoral thesis is to develop a microfluidic device for the reduction of micro-organisms from semen for the daily semen processing in the veterinary industry. It has been shown that the viability of spermatozoa after microfluidic processing is maintained for both porcine and bovine spermatozoa. The size-based separation technique pinched-flow fractionation has been applied to remove viruses from semen while maintaining high spermatozoa recoveries. For the separation of bacteria from semen, a separation technique using acoustic waves, known as acoustophoresis, has been applied. The need to process several hundreds of milliliter within an acceptable amount of time is challenging as most microfluidic applications process smaller sample volumes. Concepts to increase the sample throughput are formed to close the gap between the proof-of-principle and the actual application in industry