Abstract
The thesis presents a novel microfluidic based sperm sorting system that the whole process can be done in only one step. The difference in sperm motility or concentration between raw semen samples can be ignored before the sorting process using this device. The fabrication process of our bio-chip include SU8 thick-film photolithography and soft-lithography, which has the advantages of low-cost, high-precision, volume production, disposable, and easy to produce etc., so that it is suitable for biomedical chip. Besides, the new idea that combines both SU-8 structure and PDMS part to construct the mode have the advantage that high aspect ratio structure can be easily made without losing the precision of micro flow channel. Since the emerging of in vitro fertilization (IVF) technology and intracytoplasmic sperm injection (ICSI), assisted reproductive technology (ART) has become an important part of medical field over the past 10 years. ISCI technology focus on the genetic normality of sperm, because the process consist the direct injection of a single sperm into an oocyte; IVF technology is an natural in vitro fertilization process that come after a series of sample pre-treatment. Since the frequency of collisions between sperms and oocytes plays a key role in the fertilization, the semen property, including motility, total number, and the concentration of sperms, will directly affect the outcome. It is difficult to determine whether the genetic materials is normal or not through micro electro mechanical system (MEMS) technology, but there is a good opportunity to use a MEMS based biochips to selected the most suitable sperms before IVF process. The study is divided into two parts. In the first part, the goal is to construct a microfluidic based sperm sorting system, which focus on the screening and the classification based on sperm motility. The details including chip design, flow field simulation, and the experiments of boar semen samples are show in chapter 3. The second part improves the screening efficiency using disjunctive design, which is present in chapter 4. At the end, some ideas of future works were proposed in Chapter 5.