How much does a cell weigh? US chemists are using miniature cantilevers to find out.

'Cell mass is directly related to cell growth and division,' says Rashid Bashir at the University of Illinois at Urbana-Champaign. In an effort to understand the role a cell's mass plays in these processes, Bashir and colleagues have designed a device to measure an individual cell's mass as it grows in fluid. 

The device contains an array of functionalised silicon cantilevers overhanging microfluidic channels. As suspensions of mammalian cells flow through the channels, individual cells can be captured on the cantilevers using alternating electric fields. Once immobilised, the cells grow and their change in mass is calculated from the change in the cantilever resonance frequency. 

The team now plans to refine the method by trapping cells on suspended pedestals. This will allow them to control cell position on the cantilevers and should improve the technique's sensitivity. 

'Eventually we want to measure cell mass as a function of time,' says Bashir. He explains that directly measuring the mass of a single cell, rather than the average cell mass in a sample, ultimately could let scientists follow a single cell's mass as it progresses through the cell cycle. 'Ideally we would like to monitor one cell as it splits into two,' Bashir adds. 

Russell Johnson