[Sperm sorting based on the imitation of the physiological process on the microfluidic chip].

OBJECTIVE: To establish a new method for sperm sorting by imitating the physiological process of sperm-cervical mucus interaction on the microfluidic chip. METHODS: We designed a microfluidic chip to imitate the physiological process of natural sperm sorting in the microchannel based on the interaction between sperm and cervical mucus, and obtained motile sperm after the interaction. Meanwhile, we established an integrated real-time sperm detection reservoir on this chip to determine sperm parameters using the computer-assisted sperm analysis system. We analyzed 30 samples using both microfluidic and swim-up methods, and compared the results with those obtained before sorting. RESULTS: The rate of grade a + b sperm, the rate of morphologically normal sperm, straight-line velocity (VSL), average path velocity (VAP) and straightness (STR) were (29.78 +/- 11.24)%, (8.00 +/- 5.19)%, (18.89 +/- 4.90) microm/s, (26.84 +/- 5.13) microm/s and (70.15 +/- 7.61)%, respectively, before sorting, (71.65 +/- 11.18)%, (14.95 +/- 6.79)%, (24.14 +/- 5.95) microm/s, (32.61 +/- 6.36) microm/s and (73.87 +/- 9.34)%, respectively, after swim-up sorting, and (92.37 +/- 6.33)%, (23.33 +/- 7.67)%, (34.03 +/- 16.78) microm/s, (38.73 +/- 16.40) microm/s and (84.91 +/- 12.56)%, respectively, after sorting on the microfluidic chip. The sperm parameters obtained before sorting showed statistically significant differences from those obtained on the chip (P < 0.01) and by the swim-up method (P < 0.05). CONCLUSION: Imitation of the physiological interaction between sperm and cervical mucus on the microfluidic chip helped the realization of both the natural sorting and real-time analysis of sperm. The quality of the sperm sorted on the microfluidic chip is significantly better than that of the sperm before sorting and sorted by the swim-up method. This has prepared the ground for imitating the fertilization process under the physiological condition on the microfluidic chip.

[Effects of a microfluidic sperm sorter on sperm routine parameters and DNA integrity].

OBJECTIVE: To investigate the effects of a microfluidic sperm sorter on the routine parameters and DNA integrity of human sperm. METHODS: We divided 40 semen samples into two aliquots and performed sperm sorting using a self-made polydimethylsiloxane microfluidic sperm sorter and the swim-up method, respectively. Then we evaluated and compared the effects of these two methods on the sperm routine parameters and DNA integrity by computer-assisted sperm analysis and sperm chromatin dispersion test. RESULTS: After processing, sperm motility, normal morphology and tail hypoosmotic swelling rate were significantly improved, while sperm DNA damage remarkably decreased (P < 0.01). The microfluidic sperm sorter achieved a significantly lower rate of sperm DNA damage than the swim-up method ([ 8.4 +/- 5.8 ]% vs [16.4 +/- 9.2] %, P < 0.01), but no statistically significant differences were found in all other parameters between the two methods. CONCLUSION: High-quality sperm with less DNA integrity damage could be obtained in sperm sorting with the microfluidic sperm sorter.