The construction of an interfacial valve-based microfluidic chip for thermotaxis evaluation of human sperm

Abstract

Thermotaxis has been demonstrated to be an important criterion for sperm evaluation, yet clinical assessment of thermotaxis capacity is currently lacking. In this article, the on-chip thermotaxis evaluation of human sperm is presented for the first time using an interfacial valve-facilitated microfluidic device. The temperature gradient was established and accurately controlled by an external temperature gradient control system. The temperature gradient responsive sperm population was enriched into one of the branch channels with higher temperature setting and the non-responsive ones were evenly distributed into the two branch channels. We employed air-liquid interfacial valves to ensure stable isolation of the two branches, facilitating convenient manipulation of the entrapped sperm. With this device, thermotactic responses were observed in 5.7%-10.6% of the motile sperm moving through four temperature ranges (34.0-35.3 °C, 35.0-36.3 °C, 36.0-37.3 °C, and 37.0-38.3 °C, respectively). In conclusion, we have developed a new method for high throughput clinical evaluation of sperm thermotaxis and this method may allow other researchers to derive better IVF procedure.

Microfluidics for sperm research

“…Samples were also evaluated for the presence of sperm-specific antibodies by employing human anti-IgG antibody-coated beads. Results highlighted the advantages of multiplexed sperm CCD-coupled inverted microscope [48] Combined: pressure-and chemoattractant-driven…”

“…Thermotaxis has been demonstrated to be a significant factor in sperm quality assessment. Thermotactic assessment of human sperm was recently performed employing a microfluidic system with an interfacial valve ( Figure 2F,G) [48]. A thermal gradient was created between two branches and precisely controlled by a peripheral temperature gradient control unit.…”

“…(G) Thermal gradient formed using a control unit between the branches, N1 and N2, of the devices. Reproduced, with permission, from[48].…”

Advances in Microfluidics‐Based Assisted Reproductive Technology: From Sperm Sorter to Reproductive System‐on‐a‐Chip

“…Though not measured for human, the surgically removed rabbit oviduct showed 1.6° temperature difference along its 10 cm length. Following the initial work of Ko et al the only completed microfluidic device to study sperm thermotaxis was reported by Li et al In their design, motile sperms are first selected in a straight microchannel using the standard screening protocol. Then, the thermotactic ability of previously selected motile sperms is evaluated in a chamber, where the temperature is varied in 1.3° intervals using an external thermal controller.…”

Microfluidic assessment of swimming media for motility-based sperm selection

“…V C 2015 AIP Publishing LLC 9, 044113-1 known to cause iatrogenic transmission of genetic defects. 10,11 Recently, microfluidics emerged as a high-throughput, automated, and sensitive platform for studying gamete function, 12,13 sperm selection, 14,15 and embryo development. 16,17 Several factors urge the application of microfluidics for ARTs including: (1) providing a geometrically confined environment that closely mimics the in vivo environment, 18 (2) possibility of highly multiplexed sample analysis, 14 (3) operating with small sample volumes relevant for hypospermia (i.e.…”