Drawing of blood
components being separated by sound waves.
Image: Tony
Huang/Penn State
(September 22, 2015) Commercially
available cell sorters can rapidly and accurately aid medical diagnosis and
biological research, but they are large and expensive, present a biohazard and
may damage cells. Now a team of researchers has developed a cell sorter based
on acoustic waves that can compete with existing fluorescence-activated cell
sorters and is an inexpensive lab on a chip.
"The current benchtop cell sorters are too expensive,
too un-safe, and too high-maintenance," said Tony Jun Huang, Penn State
professor of engineering science and mechanics. "More importantly, they
have very low biocompatibility. The cell-sorting process can reduce cell
viability and functions by 30 to 99 percent for many fragile or sensitive cells
such as neurons, stem cells, liver cells and sperm cells. We are developing an
acoustic cell sorter that has the potential to address all these
problems."
Over the past decade, microfluidic cell sorters have emerged
as a promising new tool for single cell sequencing, rare cell isolation, and
drug screening. However, many of these microfluidic devices operate at only a
few hundred cells per second, far too slow to compete with commercial devices
that operate on the order of tens of thousands of operations per second. The
Penn State system can sort about 3,000 cells per second, with the potential to
sort more than 13,000 cells per second.
The researchers achieve the speed by using focused
interdigital transducers to create standing surface acoustic waves. When the
waves are not focused, the acoustic field spreads out, slowing the sorting
process. The narrow field allows the sorting to take place at high speed while
gently manipulating individual cells.