Bionics and Prosthetics: Advancing Human Abilities

 The bionic consciousness, idea, and practice opened a unique path for the progress of mankind, the development of the society, and the innovation of science and technology from the subconscious bionic activities of the ancient humans to the significant bionic designs in modern engineering. Nowadays, driven by the practical demand of human beings, bionics becomes an important factor for the sustainable development of technology. A lot of new and outstanding innovations have been produced through the effective interactions between bionics, technology, and demand.

The stronger the interactions, the greater the innovation success would be. In this article, the basic factors such as the connotation, characteristics, and interactions of bionic demands, bionic models, bionic simulations, and bionic products were explained, which are the indispensable basic knowledge for improving the ability of innovation especially for the original one, realizing the design and innovation of new technology and manufacturing for better bionic products.

The intersection of biology and technology

Biomedical engineering, the convergence of medicine, biology, and engineering, has evolved over the years in response to advances in science and technology. From the creation of the first kidney dialysis machine to the development of artificial limbs, biomedical engineering has made significant strides in improving the quality of life for many people.

Bionics and neuroprosthetics are key to these advances. These disciplines are closely linked to the development of microsystems technology, nanotechnology, information technology, biotechnology, and the application of new materials. These devices use electrical stimuli to stimulate neural structures to support, augment, or partially restore the impaired or lost function.

The science of bionics and neuroprosthetics

The foundation of bionics and neuroprosthetics is the seamless integration of biological systems with artificial mechanisms. By exploiting principles such as biocompatibility and neuroplasticity, researchers have successfully developed biomedical products that mimic natural body functions. Notable examples include Cochlear implants, retinal implants, and prosthetic limbs.

Cochlear implants work by converting sound into electrical signals that stimulate the auditory nerve directly, bypassing damaged ciliated cells, and retinal implants convert light into electrical signals that travel through the optic nerve.

Advanced prosthetic limbs have also made significant advances in mimicking natural movement. They use sensors, microprocessors, and myoelectric technology that the user's own neural signals can control.

One example is the e-OPRA implant system developed by Integrum AB. It attaches the prosthetic arm to the bone in the amputated stump, and electrodes implanted in the muscles and nerves of the amputated arm, along with an embedded connector, create an electrical interface. These electrodes connect to sensors in the body through the Integrum control system in the prosthesis. By transmitting sensory input from the prosthesis back to the user, they can control its movement.

All of these prostheses and devices operate through neural interfaces, which are the fundamental link between the biological system and the machine. Several types of neural interfaces are currently in use. Brain-computer interfaces (BCIs) are one of them.

BCIs provide a direct link between the brain and an external device, allowing individuals to control devices using their neural signals. BCIs can use invasive or non-invasive techniques such as electrocorticography (ECoG) or electroencephalography (EEG). They have shown promise in assisting people with amyotrophic lateral sclerosis, cerebral palsy, stroke, or spinal cord injury.

Other approaches include peripheral nerve interfaces, which connect peripheral nerves to the prosthetic limb to allow bidirectional communication. Techniques such as targeted muscle reinnervation (TMR) reroute nerves to activate specific muscles, allowing users to control the prosthesis more intuitively.

Finally, optogenetics-based interfaces are another promising neural interface. Optogenetics combines genetic engineering and light-sensitive proteins to control neural activity using light. This technique has shown potential for modulating neural circuits and restoring function in animal models, but its clinical application is still in the early stages of research.

A New Era for Bionic Limbs

Recent breakthroughs in science and technology have produced prosthetic hands, arms, and legs that increasingly resemble biological ones

Despite remarkable advances in the field of prosthetic limbs, existing products still aren’t meeting the needs of patients. A 2022 survey found that 44% of upper-limb amputees abandoned their prostheses, citing discomfort, heaviness of the device, and problems with functionality.

Researchers and product developers are hard at work to change that, developing a new generation of bionic limbs, which are robotic prosthetics that are controlled by signals from users. For people who have lost body parts to trauma, disease, or congenital defects, bionic limbs hold the power to restore a high degree of independence. Pioneering new surgeries, life-like materials, and touch feedback for users are some of the key innovations fueling that progress.

Making the artificial more biological

Several key technological advances have set the stage for prosthetic limbs that are more responsive, resilient, and user-friendly than their predecessors. Improvements in the primary components of robotic limbs, including microcontrollers, motors, transmission systems, batteries, artificial intelligence (AI), and machine learning have occurred in tandem over the past decade, catapulting research in the field to new heights.

Another boon for the field: 3-D printing. PSYONIC, a bionic technology company based in San Diego, has leveraged the relatively inexpensive technique to build its Ability Hand, the fastest hand on the market, but also one of the lightest and most resilient (Figure 1). Rather than using rigid materials common in the field of prosthetics—such as injection-molded plastics and custom machine steel—PSYONIC’s hand is built with soft robotics materials, including silicone and rubber, that more closely resemble human hands.

“The number one complaint we heard from patients and clinicians was that their expensive prosthetics would break easily,” said Aadeel Akhtar, Ph.D., PSYONIC’s founder and CEO. “In contrast, our own fingers are flexible and compliant, which is what makes them so impact-resistant and robust.” The Ability Hand1 has survived a range of durability tests, including punching through flaming wooden boards, breaking ice blocks, falling 30 feet, and tumbling around in a dryer for 10 minutes.

PSYONIC’s CEO and Founder, Aadeel Akhtar

Achievements and milestones

There are several successful case studies of patients benefiting from bionics and neuroprosthetics. One of the most recent examples is the case of a 27-year-old patient with unilateral obstetric brachial plexus injury (OBPI). People with severe OBPI typically face significant limitations in their daily lives due to limited hand-arm function, and traditional reconstructive methods often fail to restore their use.

This patient underwent bionic reconstruction, including elective amputation, humeral de-rotation osteotomy, and myoelectric prosthetic fitting. Functional assessments and self-reported questionnaires showed significant improvement in hand function and independence in daily activities.

Another example is the research conducted by the Cleveland Clinic in 2021, where researchers developed a groundbreaking neurorobotic prosthetic arm for upper extremity amputees. This bionic system enhanced the wearer's ability to think, behave, and function much like a person without an amputation. Combining intuitive motor control, touch, and grasp kinesthesia, the prosthetic arm provided bidirectional feedback and control.

Two participants with upper limb amputations who had undergone targeted sensory and motor reinnervation successfully tested the bionic limb, achieving a level of accuracy comparable to non-disabled individuals. These studies demonstrate the significant impact that advances in these areas can have on improving patients' quality of life.

Challenges and ethical considerations

Despite their significant advances, these fields still face several challenges and limitations. One of the main challenges is the specificity of the feedback provided by these devices. Patients often experience irritation or shock-like sensations, which can be a barrier to the successful implementation of these technologies.

In addition, there are health risks associated with implanting any device in the body, as these devices affect the neural wiring of the individual.

In addition, the long-term viability and biocompatibility of stimulation electrodes, the selection of appropriate strategies for each patient, and a better understanding of brain plasticity are some of the technical and biological challenges that remain to be overcome.

The rapid advances in bionics and neuroprosthetics also raise several ethical concerns. For example, there are issues related to informed consent, especially for patients with locked-in syndrome.

Privacy and security issues are other areas of concern. Therefore, it's important to balance the potential benefits of these technologies with their ethical implications.

Utah Bionic Leg

Prosthetic Control

Traditional prosthetic devices use a body-powered harness to control a hand device. These are easy to use. With a shrug of your shoulder, the prosthetic hand or hook opens. With the release of your shoulder, the prosthesis closes. Through the feel of the cable tension across your shoulders, you know whether the prosthesis is open or closed without looking at it.

Newer, motorized hands are not as easy to learn how to use. To close the device, you contract the remaining muscles in your arm. An electrical sensor placed over those muscles detects the contraction and tells the hand to close. Since the original muscles that controlled the hand are gone, the remaining muscles must be retrained. Learning how to open and close a prosthetic hand in this way takes some time. And you still need to watch the device to know what it’s doing.

To make motorized hands more intuitive to use, researchers are developing ways to detect the electrical signals in your brain and nerves to help control advanced bionic prosthetics. This can be done many ways, such as by implanting tiny sensors in the parts of the brain that control movement or by attaching small electrodes to the amputated nerves. Either way, the patients simply think about moving their hand and computers translate it into the movements of a bionic prosthetic hand.

Wearable Robots

Research teams are also trying to help people who have lost the use of their legs. By wearing a robotic device called an exoskeleton, some people with leg paralysis have been able to regain the ability to walk.

A group led by Dr. Thomas Bulea, a biomedical engineer at the NIH Clinical Center, created a wearable exoskeleton for children with cerebral palsy. Cerebral palsy is a brain disorder that makes it hard to stand up straight, balance, and walk. The motorized, robotic exoskeleton changes the way the children walk by helping them straighten their knees at key points during the walking cycle. While the exoskeleton can make walking easier, children must be able to navigate at least small distances on their own to use it.

“The ultimate goal really is to have a person wear this outside of our lab, or even outside of the clinical setting,” Bulea explains. “To do that you have to have a really robust control system that makes sure that the robot is behaving properly in all different kinds of environments.”

The team is now writing software so that the robotic device can be worn while navigating bumps in the terrain and other real-world conditions.

Wearable exoskeleton

Advantages of bionic limbs

Promising life-changing benefits of bionic limbs showed by long-term efficacy studies are compelling for patients. The direct attachment of the prosthesis through an osseointegrated implant has immediate benefits. It eliminates all typical burden associated with a socket, particularly the residuum’s skin problems. It eases attachment and removal of the prosthesis. It also provides a much more comfortable sitting position and allows a much larger range of movements.

There is overwhelming evidence that bionic limbs attached to osseointegrated implants significantly improve mobility. Users walk faster for longer bouts of daily and recreational activities. This is especially obvious for young and active individuals. Users of osseointegrated implants report that they feel that their prosthesis is more like a part of their body; they experience a phenomenon called osseoperception. Practically, they can feel more vibrations. This helps to feel where the prosthetic foot is on the ground and the type of surface the person is walking on. Dr Frossard has published studies showing that when compared to typical socket prostheses, bone-anchored bionic prostheses significantly improved quality of life by about 17%.

Disadvantages of bionic limbs

Occurrence and severity of adverse events with bone-anchored bionic prostheses are yet to be fully resolved. Bionic limbs can potentially cause issues with implant stability, bone fracture, breakage of the implant parts and infection. All these adverse events have several common negative effects. They cause pain. They significantly disturb the lifestyle because they limit usage of the prosthesis for prolonged duration. They also cost money paid either by the healthcare system or the users themselves as out-of-pocket expenses.

In conclusion, the advancements in bionics and prosthetics represent a transformative leap in enhancing the quality of life for individuals with disabilities. Through cutting-edge technologies and interdisciplinary collaborations, prosthetic limbs and bionic implants have become more advanced, customizable, and seamlessly integrated with the human body. These innovations not only restore lost functionality but also offer opportunities for individuals to surpass their previous limitations, empowering them to live fuller, more independent lives. As research continues to push the boundaries of what is possible, the future holds promise for even greater advancements, ultimately redefining our understanding of human potential and reshaping the landscape of healthcare and assistive technologies.