Cells are the basic functional units of all living
organisms. The current understanding of
individual cell mechanisms is still in its infancy.
A significant hurdle that severely restricts
current cellular studies is the lack of efficient
cell manipulation tools that can be used
for probing, testing and controlling cellular
behavior with micro/nano level precision.
Prof. Dong Sun and his optical tweezers cell
manipulation system
In this research, generic cell manipulation
tools have been developed and employed
to investigate the cell properties. Whole
cell manipulation tools and function
characterization are made possible by the
development of a Cell Bio-Probe, which
integrates robotics, optical tweezers, and
microfluidics in a sophisticated automated cell
testing system. Robotics has been a proven
tool for object manipulation for decades,
and has recently been extended to MEMS
devices in combination with microfluidics
lab technology. Optical tweezers is an
emerging technology, utilizing a highly
focused low-power laser beam to trap and
move suspended objects with micro/nanometer
size, providing an unparalleled means
for studying the biomechanical properties of
a large variety of medically significant nonadherent
cells. The integration of optical
tweezers into a robot-aided manipulation
system, where optical tweezers function as
specialized effectors to manipulate one or
many cells simultaneously, will open up a new
dimension for probing, testing and controlling
cellular behaviors at the single cell level.
The developed cell manipulation tools, as seen
in the figure, have been utilized to manipulate
cells in various operations, which include cell
stretching, cell transportation, cell sorting,
cell adhesion and cell fusion. An automated
system, using vision feedback, permits tests on
cells to be carried out with a high degree of
repeatability. This is significant, as much of the
testing that has been reported in other works
has been conducted under manual control,
with a high degree of variability. Being able
to conduct highly repeatable tests is critical to
obtain consistent research results. Further, the
system permits the simultaneous test of many
cells to characterize the cell properties. Microfluidic
channels with MEMS based actuated
gates will permit the flow of suspended cells
to be controlled, allowing groups of cells to
be positioned for simultaneous processing.
Control methods will be utilized to control the
motion of cells, for conducting simultaneous
tests and procedures on multiple cells.