New Bioengineered Robotic Hand Regenerates the Sensation of Touch

The sense of touch is frequently taken for granted. Losing that sense of touch can be devastating for someone without a hand or limb. While greatly sophisticated prostheses with complex moving joints and fingers are available to mimic almost every hand motion, they continue to be frustratingly complicated and unnatural for the user.

This is mostly because they lack the tactile experience that guides all their movements. This void in sensation leads to limited use or abandonment of these extremely expensive artificial devices. So why not develop a prosthesis that can in fact “feel” its environment?

That is exactly what an interdisciplinary team of scientists from Florida Atlantic University and the University of Utah School of Medicine plan to do. They are creating a first-of-its-kind bioengineered robotic hand that is capable of growing and adapting to its environment. This “living” robot will comprise of its own peripheral nervous system directly connecting robotic sensors and actuators. FAU’s College of Engineering and Computer Science is heading the multidisciplinary team that has received a four-year, $1.3 million grant from the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health for a project titled “Virtual Neuroprosthesis: Restoring Autonomy to People Suffering from Neurotrauma.”

With expertise in robotics, behavioral science, nerve regeneration, bioengineering, electrophysiology, orthopedic surgery, and microfluidic devices, the research team is developing a living pathway from the robot’s touch sensation to the user’s brain in order to help amputees control the robotic hand. A neuroprosthesis platform will allow them to explore how neurons and behavior can collectively work in order to regenerate the sensation of touch in an artificial limb.

At the center of this project is a cutting-edge robotic hand and arm produced in the BioRobotics Laboratory in FAU’s College of Engineering and Computer Science. Just like human fingertips, the robotic hand is provided with several sensory receptors that respond to variations in the environment. Controlled by a human, it is capable of sensing pressure changes, interpreting the information it receives and interacting with different objects. It alters its grip based on an object’s fragility or weight. However, the real challenge is guessing how to send that information back to the brain by employing living residual neural pathways in order to replace those that have been destroyed or damaged by trauma.

When the peripheral nerve is cut or damaged, it uses the rich electrical activity that tactile receptors create to restore itself. We want to examine how the fingertip sensors can help damaged or severed nerves regenerate, to accomplish this, we are going to directly connect these living nerves in vitro and then electrically stimulate them on a daily basis with sensors from the robotic hand to see how the nerves grow and regenerate while the hand is operated by limb-absent people.

Erik Engeberg, Ph.D., principal investigator, associate professor in FAU’s Department of Ocean and Mechanical Engineering, director of FAU’s BioRobotics Laboratory.

For the study, the neurons will not be placed in standard petri dishes. Instead, they will be positioned in biocompatible microfluidic chambers that provide a nurturing environment mimicking the fundamental function of living cells. Sarah E. Du, Ph.D., co-principal investigator, an assistant professor in FAU’s Department of Ocean and Mechanical Engineering, and a professional in the emerging field of microfluidics, has developed these small customized artificial chambers with embedded micro-electrodes. The research team will stimulate the neurons with electrical impulses from the robot’s hand in order to help regrowth after injury. They will electrically and morphologically measure in real-time how much neural tissue has been restored.

Jianning Wei, Ph.D., co-principal investigator, an associate professor of biomedical science in FAU’s Charles E. Schmidt College of Medicine, and a professional in neural damage and regeneration, will formulate the neurons in vitro, observe them grow and then see how they fare and regenerate in the aftershock of injury. This “virtual” method will provide the research team multiple opportunities to test and also retest the nerves without causing any harm to subjects.

Using an electroencephalogram (EEG) to identify electrical activity in the brain, Emmanuelle Tognoli, Ph.D., co-principal investigator, associate research professor in FAU’s Center for Complex Systems and Brain Sciences in the Charles E. Schmidt College of Science, and a professional in electrophysiology and neural, behavioral, and cognitive sciences, will analyze how the tactile information from the robotic sensors is transferred onto the brain in order to distinguish scenarios with unsuccessful or successful functional restoration of the sense of touch. Her aim is to understand how behavior helps nerve regeneration and how this nerve regeneration assists the behavior.

After the nerve impulses from the robot’s tactile sensors have passed via the microfluidic chamber, they are then sent back to the human user manipulating the robotic hand. This is done with a special device capable of converting the signals coming from the microfluidic chambers into a controllable pressure at a cuff placed on the remaining portion of the amputated person’s arm. Users will be able to identify if they are squeezing the object very hard or if they are losing their grip.  

Engeberg is also working with Douglas T. Hutchinson, M.D., co-principal investigator and a professor in the Department of Orthopedics at the University of Utah School of Medicine, who focuses in orthopedic and hand surgery. They are producing a set of tasks and behavioral neural indicators of performance that will eventually disclose how to promote a healthy sensation of touch in limb-absent people and amputees by using robotic devices. The research team is also looking for a post-doctoral researcher with multi-disciplinary experience to work on this innovative project.

This National Institutes of Health grant will help our interdisciplinary team of scientists address an important challenge that impacts millions of people worldwide, by providing a better understanding of how to repair nerve injuries and trauma we will be able to help patients recover motor functionality after an amputation. This research also has broad applications for people who suffer from other forms of neurotrauma such as stroke and spinal cord injuries.

Stella Batalama, Ph.D., dean and professor of FAU’s College of Engineering and Computer Science.

The initial stages of this project were supported by FAU’s Institute for Sensing and Embedded Network Systems (I-SENSE). Researchers also are working in partnership with I-SENSE and FAU’s Brain Institute, two of the University’s research pillars, concentrating on institutional strengths.