Study Of Sperm Sorting Using Microfluidic Chip

Objective: To study a new sorting method for motile sperm using home-made polydimethylsiloxane (PDMS) microfluidic chip. Methods: Thirty motile sperm specimens were measured by PDMS microfluidic chip in order to assess toxicity of the chip. Meanwhile, to choose a suitable separating conditions, the thirty sperm specimens were separated by different PDMS chips with three different entrance angles(30°,45°,60°)and three different channel width (120μm,180μm,250μm)of microfluidic chip sorting device respectively , and the semen parameters such as sperm motility, normal morphology and hypoosmotic swelling rate were compared before and after the experiment. Then, each of semen specimens of forty infertility men was divided into two aliquots, and processed respectively by microfluidic chip with the optimal separation efficiency and swim-up methods. Sperm routine parameters were determined using computer assisted sperm analysis (CASA); Sperm DNA integrity was determined using sperm chromatin dispersion test (SCD). Results:⑴There was no significant difference in sperm motility and survival between spermatozoa of 30 sperm specimens with and without exposure to PDMS, the average of the survival index and the average of the motility index reached 97.2% and 94.5%.⑵There were significant differences between pre-separation and post-separation in terms of sperm motility (P﹤0.01) and morphology(P﹤0.01) with microfluidic chip sorting device.⑶Comparing with three different entrance angles microfluidic chip sorting device, there were significant differences in the recovery rate of motile sperm (P﹤0.01), and with decreasing of with the entrance angles, the recovery rate of motile sperm was enhanced accordingly. But there was no difference in sperm motility and survival with three different entrance angles of microfluidic chip(P﹥0.05). (4) Comparing with three different width of micro-channel and , there are significant differences in the recovery rate of motile sperm (P﹤0.01), and with increasing of the wide of channel, the recovery rate of motile sperm was increased accordingly. But there was no difference in sperm motility and survival with three different width of micro-channel (P﹥0.05).⑸The experimental results showed there were significant differences between pre-sorting and post-sorting in terms of sperm motility (P<0.01),morphology (P<0.01) and hypoosmotic swelling rate(P<0.01) by two methods. Comparing with swim-up method, both sperm routine parameters and sperm DNA integrity by microfluidic chip sorting device were significantly increased (P<0.01). Conclusions: Microfluidic chip sorting device in the selection of sperm can get better qualitative sperm, and it is a simple, fast, small injury for sperm. The microfluidic chip sorting device provides a novel method for sorted motile, morphologically normal spermatozoa from semen without centrifugation. This technology may be useful in sorting motile spermatozoa and insemination and in vitro fertilization to improve birth health quality in future.