Day: January 17, 2025

Scientists are getting closer to something that wouldn’t look out of place in a science fiction film: bionic limbs that can sense and convey touch to their users.

In a new study published this week, researchers debuted a bionic hand system that can reportedly reproduce the most complex tactile sensations seen to date. Scientists at the Cortical Bionics Research Group developed the novel brain-computer interface (BCI) device, which was tested out by volunteers with spinal cord injuries.

Across a series of experiments, the researchers were able to translate and relay sensations tied to motion, curvature, and orientation that allowed the volunteers to perform complicated tasks with their bionic limb. The researchers say their device has now accomplished a new level of artificial touch.

There have been some important advances in prosthetic and bionic limb technology in recent years, but these limbs are currently still a long way away from fully approximating the complex nature of human touch. Some scientists have begun to use intracortical microstimulation (ICMS) of the brain’s somatosensory cortex to bridge this gap, since experiments have shown that such stimulation can produce vivid tactile sensations on people’s skin. According to study researcher Giacomo Valle, however, early attempts with ICMS have largely focused on reproducing sensation location and intensity. But there’s much more that goes into feeling something than just those two aspects.

“While contact location and force are critical feedback components, the sense of touch is far richer than this, also conveying information about the texture, material properties, local contours, and about the motion of objects across the skin. Without these rich sensations, artificial touch will remain highly impoverished,” Valle told Gizmodo. In their new study, published Thursday in Science, Valle and his team believe that they’ve gone a crucial step further with ICMS.

The researchers recruited two people with spinal cord injuries for their experiments. The volunteers were first given brain implants in the sensory and motor regions of the brain that govern the hands and arms. Via these implants, the researchers recorded and then deciphered the different patterns of electric activity produced by the volunteers’ brains as they thought about using their paralyzed limbs. The volunteers were then connected to a BCI device that acted as a bionic limb. With their thoughts alone, the volunteers could control the limb, which was outfitted with sensors that communicated with the brain implants. The researchers were then able to translate and send more complex sensations related to touch through the bionic limb into the volunteers’ brain implants.

“In this work, for the first time, the research went beyond anything that has been done before in the field of brain-computer interfaces—we conveyed tactile sensations related to orientation, curvature, motion and 3D shapes for a participant using a brain-controlled bionic limb,” said Valle, a bionics researcher at Chalmers University of Technology. “We found a way to type these ‘tactile messages’ via microstimulation using the tiny electrodes in the brain, and we found a unique way to encode complex sensations. This allowed for more vivid sensory feedback and experience while using a bionic hand.”

The volunteers could not only feel more layered sensations like touching the edge of an object—these sensations felt as if they were coming from their own hands. The added input also appeared to make it easier for the volunteers to perform complex tasks with the bionic limb more accurately, such as moving an object from one place to another. And it’s this richness, Valle said, that “is crucial for achieving the level of dexterity, manipulation, and a highly dimensional tactile experience typical of the human hand.”

These are still early days, the researchers note. More complex sensors and robotic technology, such as prosthetic skin, will be needed to truly capture the sensations that researchers can now encode and convey to a user, Valle says, and more advanced brain implants will also be needed to increase the array of sensations that can be stimulated. But Valle and his team are hopeful that such advances can be made, and that a truly human-feeling bionic limb is well within the realm of possibility.

“Although many challenges remain, this latest study offers evidence that the path to restoring touch is becoming clearer. With each new set of findings, we come closer to a future in which a prosthetic body part is not just a functional tool, but a way to experience the world,” he said.

The immediate next phase of Valle and his team’s research will be to test their BCI systems in more naturalistic settings, such as at patients’ homes. And their ultimate goal is to improve the independence and quality of life of people with disability.

Imagine armor as light as fabric yet stronger than steel, built from materials that link together like molecular chainmail. Scientists may have just taken the first step toward making it a reality.

A team of researchers led by Northwestern University scientists has developed what might be the first two-dimensional (2D) mechanically interlocked material, similar to links in chainmail. The material, detailed in a January 16 study published in the journal Science, is exceptionally flexible and strong, with promising applications in products such as lightweight body armor and ballistic fabrics.

The researchers built the material on a nanoscale level, meaning its individual components are measurable in nanometers. It’s technically a polymer: a substance made of large molecules, which are themselves made up of smaller chemical units called monomers. Examples of polymers include proteins, cellulose, and nucleic acids.

The 2D mechanically interlocked material is a polymer structure that uses mechanical bonds—bonds with physical interlocking, as opposed to, for example, covalent bonds, which usually make up polymers and involve the sharing of electrons. The material features 100 trillion mechanical bonds per 0.16 square inch (1 square centimeter), which is the highest density of mechanical bonds ever made, according to the researchers.

“We made a completely new polymer structure,” said study co-author William Dichtel of Northwestern University in a university statement. “It’s similar to chainmail in that it cannot easily rip because each of the mechanical bonds has a bit of freedom to slide around. If you pull it, it can dissipate the applied force in multiple directions. And if you want to rip it apart, you would have to break it in many, many different places. We are continuing to explore its properties and will probably be studying it for years.”

The biggest challenge in creating mechanically interlocked molecules lies in figuring out how to guide polymers into forming mechanical bonds. Madison Bardot of Northwestern University, who led the study, is credited with coming up with a new method to achieve this. The team positioned x-shaped monomers into a crystalline structure (a specific ordered arrangement) and reacted the crystals with another molecule. This reaction created mechanical bonds within the crystals. The final product is 2D layers of interlocked polymer sheets made of these bonds between X-shaped monomers, whose gaps researchers filled with more X-shaped monomers.

“It was a high-risk, high-reward idea where we had to question our assumptions about what types of reactions are possible in molecular crystals,” said Dichtel. The resulting material is incredibly strong, yet still flexible and easy to manipulate, because the individual sheets of interlocked molecules come apart from each other when the polymer is dissolved in a solvent.

“After the polymer is formed, there’s not a whole lot holding the structure together,” he added. “So, when we put it in solvent, the crystal dissolves, but each 2D layer holds together. We can manipulate those individual sheets.”

While previous researchers had made mechanically bonded polymers in very small quantities that would have been difficult to mass produce, the team’s new method is surprisingly scaleable. They made over one pound (0.5 kilograms) of the material, and suggest the possibility of making even more.

Even a small percentage of the new polymer structure, however, can improve other substances. The researchers made a material composed of 97.5% Ultem fiber (an extremely tough material in the same family as Kevlar) and 2.5% of the 2D polymer, and concluded that the mixture had made the former significantly stronger.

“We have a lot more analysis to do, but we can tell that it improves the strength of these composite materials,” Dichtel continued. “Almost every property we have measured has been exceptional in some way.”

This incredibly strong and flexible material might just be the armor the future has been waiting for.