Integration of sperm motility and chemotaxis screening with a microchannel-based device.
BACKGROUND
Sperm screening is an essential step in in vitro fertilization (IVF) procedures. The swim-up method, an assay for sperm motility, is used clinically to select the ideal sperm for subsequent manipulation. However, additional parameters, including acrosome reaction capability, chemotaxis, and thermotaxis, are also important indicators of mammalian sperm health. To monitor both sperm motility and chemotaxis simultaneously during sperm screening, we designed and constructed a microdevice comprising a straight channel connected with a bibranch channel that mimics the mammalian female reproductive tract.


METHODS
The width and length of the straight channel were optimized to select the motile sperms. We selectively cultured cumulus cells in the bibranch channel to generate a chemoattractant-forming chemical gradient. Sperm chemotaxis was represented by the ratio of the sperm swimming toward different branches.


RESULTS
The percentage of motile sperms improved from 58.5% (3.8%) to 82.6% (2.9%) by a straight channel 7 mm in length and 1 mm in width. About 10% of sperms were found to be chemotactically responsive in our experiment, which is consistent with previous studies.


CONCLUSIONS
For the first time, we achieved the combined evaluation of both sperm motility and chemotaxis. The motile and chemotactically responsive sperms can easily be enriched on a lab-on-a-chip device to improve IVF outcome.
Xie
Lan
L
Medical Systems Biology Research Center, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing, China.
Ma
Rui
R
Han
Chao
C
Su
Kai
K
Zhang
Qiufang
Q
Qiu
Tian
T
Wang
Lei
L
Huang
Guoliang
G
Qiao
Jie
J
Wang
Jundong
J
Cheng
Jing
J
D000818:Animals; D002478:Cells, Cultured; D002633:Chemotaxis; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D044085:Microfluidics / Q000295:instrumentation; D013081:Sperm Motility; D013094:Spermatozoa / Q000502:physiology*