A major breakthrough in the study of diseases has been achieved by scientists at Ecole Polytechnique Federale De Lausanne (EPFL). The team has been able to successfully create ways to stimulate cells and microtissue in vivo and in vitro mechanically.
The researchers led by Selman Sakar developed micromachines that can carry out complicated manipulation tasks under physiological conditions on a microscopic scale. These new tools will help doctors and scientists better understand the conditions that cause disease.
Artificial muscles move tiny tools
The powerful tools are powered by cell-sized artificial muscles. The set of tools are made up of microactuators and soft robotic devices which are wirelessly activated by laser beams that can perform both chemical and mechanical stimulation of a variety of biological samples.
"We wanted to create a modular system powered by the contraction of distributed actuators and the deformation of compliant mechanisms," said Sakar. The complete system is assembled in an almost Lego brick-like fashion from various hydrogel components.
Once a compliant skeleton is attained, tendon-like polymer connections are added between the skeleton and the microactuators. By assembling the bricks and actuators in different ways, scientists can create an array of complicated micromachines.
"Our soft actuators contract rapidly and efficiently when activated by near-infrared light. When the entire nanoscale actuator network contracts, it tugs on the surrounding device components and powers the machinery," said Berna Ozkale, the study's lead author.
Using this method the scientist can activate multiple microactuators at specified locations that open many possibilities for research.
The authors of the paper that detail their new approach say their new technology could be adapted by doctors for use in medical implants to stimulate tissue mechanically.
It could also be used as an on-demand method of delivery of biological agents. The research is published in Lap on a Chip.
Hydrogel remembers shapes
Sakar’s lab is also involved in another exciting project that is developing novel ways to pick up and transport microscopic objects in a liquid environment independent of their shape or size.
Unlike using actuated fingers, this new way of transport does not require an understanding of the object's shape nor does the grip mechanism need to be pre-set.
The system works by using a hydrogel that can ‘remember its original shape.' When the gel is placed next to an object within a tube, it engulfs the object and replicates its shape, Calcium ions are added to the tube, and the hydrogel becomes a solid.
This solid can then be used to transport the object. To release the object the calcium ions are swapped out for potassium ions, thus making the ball soft again.
“The hydrogel can take on a variety of shapes, making it a kind of universal gripper,” says Haiyan Jia, the lead author.