Scientists from the Netherlands have designed a chip that calculates sperm cell concentration in semen and could be used as an at home fertility test. 

Counting sperm in semen is a key parameter used to assess male fertility. Current methods involve taking a sample to a laboratory technician who manually counts the number of sperm in a specific volume using a microscope. As well as the inconvenience of getting the sample to the lab quickly, results from this procedure often appear to be subjective and it requires manual handling of the sample says Loes Segerink at the University of Twente, Enschende. 

The chip developed by Segerink and colleagues consists of a microchannel containing a pair of electrodes which measure the impedance of the fluid at a certain frequency. Different cells present in the semen are distinguished by the size of the impedance signal. Doping the sample with a known quantity of latex beads and comparing the ratio of bead signals to sperm signals allows calculation of the sperm concentration. 

'The device makes objective determination of the concentration possible without extensive manual handling, subjective analysis or an expensive system. Furthermore it can be used at places outside the laboratory, for instance at home,' says Segerink. Other parameters used to assess semen quality could also be integrated onto the chip, she adds, which could lead to handheld devices for fertility testing at home. 

David Holmes, an expert on microdevices that use impedance spectroscopy for cell sorting, from the London Centre for Nanotechnology, UK, says 'The technique is extremely powerful as it represents a label-free method of cell analysis. Improvements in the sensitivity of these devices will ultimately result in the development of simple to use fertility analysers.' 

Jennifer Newton 

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