Chip developed to provide men with home fertility tests
26 January 2010
A revolutionary DIY sperm count testing kit has been developed by scientists that will give men the easiest option of determining their fertility.
Until now, men had to take their sample to the hospital within one hour to get it checked by a lab technician, repeated several times over a two to three week period. With a microfluidic chip, there is no need for the technician anymore and the analysis can be done at home and saved. Previous problems, such as the labour intensive technique of visually counting sperm by putting the semen into a counting chamber, have led to further research into the development of an affordable and easier alternative. The breakthrough is described in the Royal Society of Chemistry's journal Lab on a Chip.
Dutch scientists at the University of Twente overcame the problems of manual testing by creating a microfluidic chip that can be used by men at convenient moments at home. When the system is used, the man receives a message if the measurement went well, but not what the values are. After some measurements at different days, the couple return to hospital where a gynaecologist reads out the system and decides what will be the next steps in the treatment.
The chip works by taking an electrical reading of spermatozoa related to the counting of polystyrene beads added in a known concentration to the semen sample. The measurement is made easier because there is no need to accurately measure the fluid flow through the chip, as used in hospitals, with this internal calibration method.
Sperm count is usually recorded in millions of sperm per millilitre of semen. The recognised cut off level recommended by the World Health Organisation (WHO) is 20 million sperm cells per ml. A normal count is regarded as being greater than 20 million per ml.
"Visual counting the spermatozoa in the semen by putting the semen into a counting chamber is the gold standard for this determination," the paper states. "This labour intensive method is in larger hospitals replaced by a computer assisted semen analysis system. The results of the manual test are often subjective and can hardly be compared between different laboratories, while the computer assisted semen analysis system is expensive and needs comprehensive quality control. In addition, only reliable results are obtained after analysis of at least three consecutive samples.
"To overcome the problems of the current procedure, we present here a microfluidic chip that can be used by the man himself at convenient moments at home. This is the first time that the concentration of spermatozoa has been determined on chip using electrical impedance measurements without a need to know the actual flow speed.
Co-author Loes Segerink told the Royal Society of Chemistry: "The concentration is an important parameter, but still other parameters like the motility need to be assessed as well before a good statement about the fertility can be done. The determination and integration of these parameters on the microfluidic chip will be investigated in future work, such that at the end a complete quality analysis of semen on chip is possible."
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