Tiny nano-sized packets called vesicles, also known
as exosomes, are secreted from cells
and often carry important biological messages related
to health or disease states.
Currently, the only way to isolate these vesicles
from blood is by using modern cell-sorting technologies,
such as taggings with chemicals or exposing them
to strong mechanical forces that could damage them.
But now, a multi-disciplinary team
of researchers from MIT and elsewhere
has developed a novel, much gentler, method
using sound waves to isolate exosomes directly
from the undiluted blood.
Their new microfluidic device includes two subunits,
each containing a pair of slightly tilted transducers.
When sound waves produced by these transducers
encounter one another, they generate
a series of pressure nodes.
Each time a cell or particle flowing through the channel
encounters a node, the pressure guides the cell particle
in a particular direction to isolate it and ultimately
In the first unit of their device,
there is a lower driving frequency,
which isolates larger particles such as red and white blood
cells and platelets.
The second unit has a much higher driving frequency
and therefore is able to separate the smaller
nanoparticles and isolate the exosomes from the remaining
The new method takes less than 25 minutes to process, as
compared to hours or even days using a centrifuge.
The device is also portable, economical,
and offers the potential to preserve the characteristics
and functions of isolated exosomes.
The researchers hope this automated point-of-care device
can help with health monitoring, disease diagnosis,