Drexel's microswimmer robot chains can decouple and reconnect in a magnetic field
Drexel University researchers, led by MinJun Kim, PhD, a professor in the College of Engineering, have successfully pulled off a feat that both sci-fi fans and Michael Phelps could appreciate. Using a rotating magnetic field they show how multiple chains of microscopic magnetic bead-based robots can link up to reach impressive speeds swimming through in a microfluidic environment. Their finding is the latest step toward using the so-called "microswimmers" to deliver medicine and perform surgery inside the body.
In a paper recently published in Nature Scientific Reports, the mechanical engineers describe their process for magnetically linking and unlinking the beads while they're swimming, and individually controlling the smaller decoupled robots in a magnetic field. This data helps further the concept of using microrobots for targeted, intravenous drug delivery, surgery and cancer treatment.
"We believe microswimmer robots could one day be used to carry out medical procedures and deliver more direct treatments to affected areas inside the body," said U Kei Cheang, PhD, a postdoctoral research fellow in Drexel's College of Engineering and lead author of the paper. "They can be highly effective for these jobs because they're able to navigate in many different biological environments, such as the blood stream and the microenvironment inside a tumor."
One of the central findings is that longer chains can swim faster than shorter ones. This was determined by starting with a three-bead swimmer and progressively assembling longer ones. The longest chain examined by the group, 13-beads in length, reached a speed of 17.85 microns/second.
Drexel engineers have been adding the understanding of microrobots for biomedical applications for nearly a decade, with the goal of producing a robotic chain that can travel inside the body, then decouple to deliver their medicinal payload or targeted treatment.
The reason for this approach is that a rather versatile robot that can do multiple tasks could be controlled using a single magnetic field.
The robot chains move by spinning, like a long screw-like propeller in step with a rotating external magnetic field. So the faster the field rotates, the more the robots spin and the faster they move. This dynamic propulsion system is also the key to getting them to divide into shorter segments. At a certain rate of rotation the robotic chain will split into two smaller chains that can move independently of each other.
"To disassemble the microswimmer we simply increased the rotation frequency," Cheang said. "For a seven-bead microswimmer, we showed that by upping the frequency 10-15 cycles the hydrodynamic stress on the swimmer physically deformed it by creating a twisting effect which lead to disassembly into a three-bead and four-bead swimmer."
Once separate, the field can be adjusted to manipulate the three and four-bead robots to move in different directions. Because the beads are magnetized, they can eventually be reconnected -- simply by tweaking the field to bring them back into contact on the side with the corresponding magnetic charge. The team also determined optimal rotation rates and angle of approach to facilitate re-linking the microswimmer chains.
This finding is a key component of a larger project in which Drexel is partnering with 10 institutions of research and medicine from around the world to develop this technology for performing minimally invasive surgery on blocked arteries.
"For applications of drug delivery and minimally invasive surgery, future work remains to demonstrate the different assembled configurations can achieve navigation through various in vivo environments, and can be constructed to accomplish different tasks during operative procedures," the authors write. "But we believe that the mechanistic insight into the assembly process we discussed in this research will greatly aid future efforts at developing configurations capable of achieving these crucial abilities."
link to video: https:/
Britt Faulstick | EurekAlert!
Novel breast tomosynthesis technique reduces screening recall rate
21.02.2017 | Radiological Society of North America
Biocompatible 3-D tracking system has potential to improve robot-assisted surgery
17.02.2017 | Children's National Health System
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
22.02.2017 | Power and Electrical Engineering
22.02.2017 | Life Sciences
22.02.2017 | Physics and Astronomy