Hum. Reprod. Advance Access originally published online on September 30, 2005
Human Reproduction 2006 21(2):477-483; doi:10.1093/humrep/dei323
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IVF within microfluidic channels requires lower total numbers and lower concentrations of sperm
1 Department of Urology, 2 Department of Biomedical Engineering, 3 Department of Macromolecular Science and Engineering, 4 Department of Obstetrics and Gynecology and 5 Department of Molecular and Integrated Physiology, University of Michigan, Ann Arbor, MI 48109, USA
6 To whom correspondence should be addressed at: 6428 Medical Sciences I, 1301 E Catherine St, Ann Arbor, MI 48109-0617, USA. E-mail: smithgd{at}med.umich.edu
BACKGROUND: Microfluidic technology has been utilized in numerous biological applications specifically for miniaturization and simplification of laboratory techniques. We sought to apply microfluidic technology to murine IVF. METHODS: Microfluidic devices measuring 500 µm wide, 180 µm deep, and 2.25 cm in length were designed and fabricated using poly(dimethylsiloxane) (PDMS). Controls were standard centre-well culture dishes with 500 µl of media, half of which also contained PDMS as a material control. Denuded mouse oocytes were placed into microchannels or centre-well dish controls in groups of 10, then co-incubated overnight with epididymal mouse sperm at various concentrations. Fertilization was assessed and Fisher’s exact test was used for statistical analysis (P < 0.05 significant). RESULTS: Fertilization rates between the two control groups (42%, no PDMS; 41%, with PDMS; not significant) were similar. Fertilization rates for denuded oocytes at standard mouse insemination sperm concentration (1°106 sperm/ml) was poorer in microchannels (12%) than controls (43%; P < 0.001). As insemination concentrations decreased, fertilization rates improved in microchannels with a plateau between 8°104 and 2°104 sperm/ml (4000–1000 total sperm). At these concentrations, combined fertilization rate for denuded oocytes was significantly higher in microchannels than centre-well dishes (27 versus 10%, respectively; P < 0.001), and was not significantly different from corresponding controls with a sperm concentration of 1°106 (37%; P = 0.06). CONCLUSIONS: Murine IVF can be conducted successfully within microfluidic channels. Lower total numbers and concentrations of sperm are required. Microfluidic devices may ultimately be useful in clinical IVF.
Key words: IVF/microfluidics/murine/sperm