A way of monitoring cell respiration in microchips could lead to better devices for fertility research.

Microfluidic devices are used to manipulate biological cells, for example, in sorting human sperm, but information on how well the cells are surviving within such microchips can be limited. Now, Hitoshi Shiku at Tohoku University, Sendai, Japan, and colleagues have used a technique called scanning electrochemical microscopy (SECM) to monitor individual cells in a microfluidic device by measuring their oxygen uptake. 

Shiku and colleagues developed their method using a channel filled with Escherichia coli cells as a model of a microfluidic device. One face of the channel was formed from a membrane through which oxygen could flow freely and the team used SECM to measure the oxygen concentration along this face. Shiku's co-worker Takeshi Saito said that because the measurement takes place on the other side of an oxygen-permeable membrane, disturbance to the cells is avoided. 

Shiku found that oxygen uptake levels for the cells in his model device differed from values reported for similar cells trapped in collagen gels. This means the dimensions and material of a chip affect oxygen uptake and therefore how well the cells survive, said Shiku. Being able to monitor cell respiration in this way should lead to improved designs for chips for biological research, he added.

Commenting on the work, Salvatore Daniele, an expert in electrochemistry from the University of Venice, Italy, said that the main advantage of the approach was its potential for continuous monitoring of cell activity in very small volume samples.

Future work will involve applying the method to other cell suspensions such as semen and Saito says that this technology could have a role in studies aimed at improving human fertility. 

Michael Smith