Freezing cells inside glass cages could potentially improve human fertility treatments.

Utkan Demirci and Grace Montesano, at Harvard Medical School and the Massachusetts Institute of Technology, in Cambridge, US, have developed the first high-throughput cell vitrification method for automated cell preservation. Demirci and Montesano's research involves cell encapsulation in droplets; 'the aim is to apply the technology to real problems in medicine,' said Demirci.  

Demirci and Montesano's cell preservation method works by trapping single cells in droplets of a cryoprotectant - a liquid that prevents cell damage on freezing - and the droplets are then vitrified. Vitrification is a rapid freezing process in which a fluid turns into a glass-like solid without crystal formation. The new procedure can preserve cells at rates as high as thousands of cells per second while retaining cell viability. It also allows lower concentrations of toxic cryoprotectant such as 1,2-propanediol to be used, leading to significantly reduced osmotic stress on the cells. Furthermore, automation avoids human error and minimises mechanical stress to the cells due to manual handling.

Vitrified cells (left) can be thawed (right) and remain viable

Among the different cells preserved were liver cells and mouse embryonic stem cells and Demirci suggests that future work could provide controlled vitrification methods for reproductive (germ) cell preservation. 'This could have impact in extending human fertility, allowing higher yields and success,' said Demirci. 'One challenge in vitrifying germ cells is their larger size compared to other cell types. We will optimise our system to address challenges in this arena by changing the droplet sizes and concentrations.' 

David Juncker, an expert in high-throughput cell analysis from McGill University, in Montreal, Canada, explained that 'cell preservation and manipulation is of great interest. The method seems versatile,' he added, 'I could imagine using it for rare stem cell collection and conservation.' 

Kathleen Too