The Short:
Newscientist reports that researchers at the University of Toronto have created a microgripper device capable of grabbing and releasing objects as small as a cell. Tiny tweezers or grippers have been created by several researchers over the years, but what makes this microgripper unique is its sense of touch. From the article:

“The robotic gripper can exert as little as 20 nanoNewtons of force and are the first to be able to feel the strength of their grip on objects so delicately, says Yu Sun of the University of Toronto in Canada, who led their development.”

“The grippers are the first to not only feel their grip strength, but
also when they touch a surface. This allows them to sense when they’ve
run into things, helping them get close to cells and other objects
without damaging collisions.”

The Long:

The original research article can be found here. A few other interesting quotes:

“This paper reports on a monolithic MEMS-based microgripper with integrated force feedback along two axes and presents the first demonstration of forcecontrolled micro-grasping at the nanonewton force level”

“The tweezers’ arms are about 3 millimetres long, with fine tips able
to grasp cells just 10 micrometres across. In trials using pig heart
cells, the pincer could pick up and move the cells without damaging
them. Holding them with only 100 nanoNewtons of force, the gripper
squashed the cells out of shape by only 15%.”

“The grippers are controlled by software that can identify individual cells
and move the tweezers into position in just a few seconds. That’s much
faster than a person could do, Sun says.”

An amazing series of photos is presented below, showing how the microgripper was used to take three randomly placed cells and move them into a straight line:

Figure 11. Cell manipulation and alignment with force-controlled micrograsping. (a) After contact detection, the microgripper grasps a first cell. (b) The microgripper transfers the cell to a new position and releases the cell. (c) The microgripper grasps a second cell. (d) Transferring and releasing the second cell. (e) The microgripper approaches a third cell. (f) Transferring and releasing the third cell. Three cells of different sizes are transferred to desired positions and aligned.

Images are from the research article