Unhealthy cells are less “squishy” than their healthy counterparts. That difference is used by a small device developed by engineers at Monash University to test living blood cells for diseases, such as malaria and diabetes. The device can then sort the cells for future culturing and experimentation without harming them.
The patented “lab-on-a-chip” and accompanying control system has attracted considerable interest from pharmaceutical companies, according to co-inventor Dr Greg Sheard of the Department of Mechanical and Aerospace Engineering.
“When blood cells become unhealthy, their mechanical properties alter,” he says. “There’s increasing evidence showing they lose their squishiness—their membrane stiffness, internal viscosity and deformability all change.”
The new device, which is about the size of a microscope slide, can assess that. But its operation depends on an understanding of fluid flows and on simulations involving the complex equations of computational fluid dynamics. That’s why its inventors needed access to the supercomputers at the Victorian Life Sciences Computation Initiative to design it.
The chip is marked with micro-channels about a tenth of a millimetre wide in the shape of a cross. At the end of the arms are portals through which fluid can be injected or withdrawn. By careful management and control of the fluid flows down each arm, individual blood cells, less than a hundredth of a millimetre in diameter, can be drawn into the centre of the cross.
At this point they are subjected to a fluid pulse, and their deformation assessed and recorded using high speed photography. On the basis of the result the blood cells can be sorted and ejected down one of two exit arms.