Progressive Sperm Separation Using Parallelized, High-Throughput, Microchamber-based Microfluidics

Abstract

Motility is one of the most important factors in sperm migration toward egg. Therefore, sperm separation based on motility increases the chance of the best sperm selection in the process of infertility treatments. Unfortunately, it is now vastly done by conventional procedures which lack certain delicacy and precision and increase the risk of damage to sperm cells. Microfluidic systems, on the other hand, can sort sperm in a less intrusive way. However, microfluidic techniques have yet to receive widespread adoption in clinical settings, not only due to their relatively cumbersome operation, but also their extremely low outcome, leaving them inefficient in practice. Here we propose a microchamber-based microfluidic platform that can separate progressive motile sperm from nonviable sperm and debris as well as trapped nonprogressive sperm in the microchambers. Our platform is operated in a short period of time (<10 min) with an excellent degree of controllability, without any prior sample preparation. Our results show that the microchambers depth does not affect the residence time of motile sperm. Therefore, we are able to inspect high sample volumes (1 mL) within the same time. Furthermore, we maximize the concentration of the collected sperm by tuning the washing medium flow rate above the sperm rheotactic threshold. We foresee that our microfluidic platform may provide a facile solution for high-throughput, robust, and easy-to-modify for collection of progressive sperm needed for assisted reproductive technologies (ARTs).

Gradient-Based Microfluidic Platform for One Single Rapid Antimicrobial Susceptibility Testing

“…We demonstrate a high-throughput gradient-based microfluidic (i.e., GM 2 ) platform that can be used to probe the effects of antibiotic drug efficacy on a clinically isolated bacterial species (Figure a). Our GM 2 device consists of two PDMS and glass slide pieces, fabricated by using a conventional soft lithography technique (Figure a). ,− The GM 2 platform is made of four openings (A–D) and microchambers connected to the main channel via side channels (Figure a). The dimensions of different parts of microchambers and side channels are shown in the inset of Figure a.…”

“…We followed the instruction provided by Microchem (Westborough, MA) for the GM 2 device fabrication. − In detail, the design of the GM 2 platform was patterned on a silicon wafer by SU-8 2050, using a well-established soft lithography technique. In detail, we used spin-coating (speed = 2800 rpm and time = 2 min) and patterned a thin 70 μm SU-8 2050 on a precleaned silicon wafer.…”