Applications of

have been designed and fabricated in silicon for use in various analytical tasks. We studied sperm motility and performed sperm selection in channels (80 p.m wide x 20 p.m deep), branching structures (40 p.m wide x 20 p.m deep, eight bifurcations), and channels containing barri-ers (7 p.m feature size). Sperm-cervical mucus and sperm-hyaluronic acid interactions were assessed by us-ing appropriate microchannel-chamber structures filled with either cervical mucus or hyaluronic acid. Simultane-ous assessment of the potency of different spermicides (e.g., nonoxynol-9, Cl 3G) and spermicide concentrations was achieved with structures comprising chambers con-taining spermicide connected via channels to a central chamber into which semen was introduced. Semen was also tested for the presence of sperm-specific antibodies by using microchannels filled with human anti-lgG anti-body-coated microbeads. Indexing Terms: fertility/infertility studies immunoassay spermicide microscopy Semen analysis is a key component in the evaluation of male infertility. Various tests are performed on a semen sample, including determination of motility, morphology, viability, interaction with cervical mucus, and the presence of anti-sperm antibodies (1). Motility is assessed conventionally either by estimating the rel-ative percentage of motile sperm through use of a hemo-cytometer, a Makier Counting Chamber (2), or comput-er-assisted semen analysis (1, 3). Motility of sperm, especially linear motility, is a very important measure-ment. One difficulty with the existing motility tech-niques is that sperm motion must be determined in several directions in a chamber or on a slide. We rea-soned that constraining sperm in a channel would sim-plify assessment of motility because one would need to determine the movement of sperm in only one direction along the channel. We have investigated, therefore, the application of microchanels fabricated in silicon by conventional lithographic techniques (Figure IA) for determining sperm motility and assessing other aspects of sperm function