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Tech Front: Device Lures Cancer Cells Away from Organs


A small, implantable device that researchers are calling a cancer “super-attractor” could eventually give doctors an early warning of relapse in breast cancer patients and even slow the disease’s spread to other organs in the body.

The sponge-like device developed at the University of Michigan is designed to attract the cancer cells that emerge in the bloodstream during the early stages of cancer’s recurrence—before tumors form elsewhere in the body. A new study in mice shows that the device attracts detectable numbers of cancer cells before they’re visible elsewhere in the body. It also shows that the cancer cells spread to the lungs 88% more slowly in the mice that received the implants. Cancer cells also spread more slowly to the liver and other organs. The team’s findings are reported in a new paper published in the journal Nature Communications.
Conceptual illustration of implantable sponge-like device that attracts cancer cells from the bloodstream.
“Breast cancer is a disease that can recur over a long period in a patient’s life, and a recurrence is often very difficult to detect until the cancer becomes established in another organ,” said Jacqueline Jeruss, an associate professor of surgery in the U-M Comprehensive Cancer Center and an author on the paper.

Jeruss said the idea for the super-attractor was born from the knowledge that cancer cells don’t spread randomly. Instead, they’re attracted to specific areas within the body. So the team worked to design a device that exploited that trait.

“We set out to create a sort of decoy—a device that’s more attractive to cancer cells than other parts of the patient’s body,” explained U-M Biomedical Engineering Professor Lonnie Shea, an author on the paper. “It acts as a canary in the coal mine. And by attracting cancer cells, it steers those cells away from vital organs.”

The device’s spongy structure is particularly attractive to circulating cancer cells. It’s made of an FDA-approved material that’s already widely used in surgical sutures and harmlessly dissolves in the body over time.

When the super-attractor was implanted just beneath the skin of the mice in the study, their cancer-compromised immune systems responded as they would to any foreign object, sending out cells to attack the intruder. Cancer cells were then attracted to the immune cells within the device, where they took root in tiny pores designed to be hospitable to them. The study also found that the cells captured by the implant didn’t group together into a secondary tumor, as they normally would.

“We were frankly surprised to see that cancer cells appeared to stop growing when they reached the implant,” Shea said. “We saw individual cells in the implant, not a mass of cells as you would see in a tumor, and we didn’t see any evidence of damage to surrounding tissue.

The device implanted in the mouse study was only a few millimeters in diameter; a human-sized version might be a bit larger than a pencil eraser. The team is now working to gain a better understanding of why cancer cells are attracted to specific areas of the body and why they’re so strongly attracted to the device.


“RoboBee” Research Goes Swimmingly at Harvard

So far, they’ve been limited to science-fiction films and comic books, but now, thanks to biomimetics, the flying submarine may be one step closer to reality. Engineers have been trying to design functional aerial-aquatic vehicles for decades with little success. The biggest challenge is conflicting design requirements: aerial vehicles require large airfoils like wings or sails to generate lift while underwater vehicles need to minimize surface area to reduce drag. It is hard to imagine such a craft that wasn’t, well, a fish out of water.

To solve this, engineers at the Harvard John A. Paulson School of Engineering and Applied Science (SEAS) turned to biomimetics—the imitation of aspects of nature for the purpose of solving complex problems. In this case, they studied not a flying fish but an aquatic bird that is able to swim under the surface of the water for long periods—the puffin. The bird employs similar flapping motions to propel itself through air as through water.

“Through various theoretical, computational and experimental studies, we found that the mechanics of flapping propulsion are actually very similar in air and in water,” said Kevin Chen, a graduate student in the Harvard Microrobotics Lab at SEAS. “The only difference is the speed at which the wing flaps.”
Harvard researchers have demonstrated an insect-scale robot that can swim as well as fly.
This research was presented recently in a paper at the International Conference on Intelligent Robots and Systems in Germany, where first author Chen accepted the award for best student paper. The paper was co-authored by Farrell Helbling, Nick Gravish, Kevin Ma and Robert Wood.

The device that they used to mimic the puffin’s aerial-aquatic abilities is the Harvard RoboBee—a microrobot, smaller than a paperclip, that flies and hovers like an insect, flapping its wings 120 times per second. In order to make the transition from air to water, the team first had to solve the problem of surface tension. The RoboBee is so small and lightweight that it cannot break the surface tension of the water. To overcome this hurdle, the RoboBee hovers over the water at an angle, momentarily switches off its wings, and crashes into the water in order to sink.

Next the team had to account for water’s increased density. “Water is almost 1000 times denser than air and would snap the wing off the RoboBee if we didn’t adjust its flapping speed,” said Helbling, the paper’s second author. The team lowered the wing speed from 120 flaps per second to nine but kept the flapping mechanisms and hinge design the same.

While this RoboBee can move seamlessly from air to water, it cannot yet transition from water to air because it can’t generate enough lift without snapping one of its wings. Solving that design challenge is the next phase of the research, according to Chen.

Exoskeleton Program off to Strong Start

An international team of researchers and companies are working to develop an exoskeleton for senior citizens so they can remain active for longer. An exoskeleton is a kind of lightweight robot skeleton with small electric motors. It gives the body support and provides extra strength to perform different types of movements.

Simon Christensen (left), Muhammad Raza Ul Islam and Shaoping Bai (right) with their first model of an AXO Suit portable robotic arm.The ‘AXO Suit’ exoskeletons that the Aalborg University researchers are working on are targeted for primarily active older people who, for example, would like to continue to be able to garden, go out for walks and manage in their own homes for a longer time. “It’s a huge design challenge to make something that feels natural and comfortable for the user,” explained Simon Christensen, a PhD student on the project.

In principle, a motorized robotic skeleton gives whoever is wearing it the opportunity for almost superhuman strength. But too much strength makes the user feel uncomfortable, noted researcher Shaoping Bai. So, he said, the performance of the electric motor is limited to a maximum of 30–50%.

“It’s important that users don’t feel that the exoskeleton is stronger than they are—in the sense that it can disempower someone,” Bai said. The sensors must be sensitive enough to be able to determine how much the motors need to help. “The biggest challenge is actually purely mechanical. It is absolutely essential that you feel that it’s you controlling the robot and not the other way around,” he said. “You must be stronger than the skeleton you have on, and we have designed the motors for this.”

The AXO Suit project is a partnership between Aalborg University; Gävle University College; the University of Limerick; Welldana; Bioservo Technologies; MTD Precision Engineering; COMmeto BVBA and Hjälpmedelsteknik, Sweden. The researchers expect to already be able to present the first portable prototype in the course of a year. When the project runs out in two years a fully functional model has to be ready.

“In five years, we expect that commercially available models will be on the market,” said Bai.

Graphene-Based Cutting Fluid Lengthens Diamond Tool Life

Diamond-based cutting tools are the go-to method for cutting high-value, hard-to-cut materials, but—no surprise—they’re expensive. For the “transition metals” of the periodic table (which include titanium, chromium, iron, nickel, cobalt and other manufacturer favorites) and their alloys, diamond-based cutting tools tend to wear out too quickly to work as a feasible option. That high rate of tool wear is caused by chemical diffusion of carbon from the diamond tool into the transition metal/alloy workpiece.

In SME’s Journal of Manufacturing Processes, a team from the Department of Mechanical, Aerospace and Nuclear Engineering at Rensselaer Polytechnic Institute (RPI, Troy, NY) report a solution—a cutting-fluid solution, that is, one that contains carbon-rich graphene oxide colloidal suspensions to mitigate carbon diffusion from the tool to the workpiece.

In “Graphene Oxide Colloidal Suspensions Mitigate Carbon Diffusion during Diamond Turning of Steel,” RPI’s Philip Smith, Bryan Chu, Eklavya Singh, Philippe Chow, Johnson Samuel, and Nikhil Koratkar describe their testing of this cutting fluid on low-carbon steel. They report that the use of graphene oxide colloidal suspension results in about a 74% reduction in tool wear compared to dry machining. It also results in a 50% reduction in cutting temperatures and a 20–30% reduction in cutting forces compared to dry machining. You can read their paper here:

Tech Front is edited by Senior Editor Michael Anderson. 


This article was first published in the December 2015 edition of Manufacturing Engineering magazine. Click here for PDF.

Published Date : 12/1/2015

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