{"id":2508,"date":"2007-07-15T17:09:37","date_gmt":"2007-07-15T21:09:37","guid":{"rendered":"https:\/\/engineering.jhu.edu\/magazine-archive\/?p=2508"},"modified":"2014-12-15T17:10:21","modified_gmt":"2014-12-15T22:10:21","slug":"body-builders","status":"publish","type":"post","link":"https:\/\/engineering.jhu.edu\/magazine-archive\/2007\/07\/body-builders\/","title":{"rendered":"Body Builders"},"content":{"rendered":"

In the time it takes to read this sentence, 50,000 cells in your body will die and be replaced with new cells. Lined up end to end, the body\u2019s more than 10 billion nerve cells would stretch 45 miles. Each day, you breathe an average of 23,040 times, and your blood makes its daily 60,000-mile trip through your body. The laundry list of what\u2019s contained in every square inch of human skin is just as mind-boggling: four yards of nerve fibers, 1,300 nerve cells, 100 sweat glands, three million cells, and three yards of blood vessels. It\u2019s all part of what is arguably the most complex engineering system on Earth: the human body.<\/strong><\/span><\/p>\n

From the intricacies and mysteries of brain function to the speed at which a sneeze leaves your mouth\u2014it can be in excess of 100 miles per hour\u2014the human body is an engineering marvel. Even more so, when you consider that outside of reproductive organs, the components are basically the same in every model, but every one of the more than 6.5 billion models on the planet is genetically unique.<\/p>\n

For all its sophistication and wonder, the human body is also a system that is prone to disease, decay, and injury. Organ failure, cancer, spinal cord injuries, blood clots, and amputations: Every day, these issues and more affect millions of people. With cutting-edge research in tissue and cell engineering and neural prosthetics, Whiting School faculty and students are helping to change the way we think about the human body\u2014and how we heal it.<\/p>\n\"JHU-ENG-MAG-SR07-124\"<\/a>\n

Brain<\/span><\/h1>\n

Noah Cowan,<\/strong> assistant professor of mechanical engineering, spends his time thinking about things most of us would rather not. Cockroaches scurrying along a wall. The eerie glow of the transparent electric knifefish. His discoveries about how the brains of these lowly creatures direct movement could eventually lead to advances in rehabilitative therapies for stroke patients, people with cerebral palsy and other debilitating conditions, and better, less jerky prosthetics. \u201cThe interface between brain and machine is only partially understood,\u201d says Cowan. \u201cOur results may one day be used to guide the design of brain-controlled prosthetic limbs so that they match our own natural performance.\u201d<\/p>\n

Cowan\u2019s Locomotion in Mechanical & Biological Systems (LIMBS) Laboratory has spent the past four years studying the way the cockroach uses thousands of antennae sensors to navigate in the dark and dash across rooms. The cockroach\u2019s brain processes sensory information as quickly as the bug speeds along a wall at a remarkable 25 body lengths per second. LIMBS researchers found that the curve of the antennae against a wall \u201creads\u201d the shape of the wall, signaling the cockroach how fast to turn.<\/p>\n

Using their data, Cowan and his students built an orange-and-black wheeled metal \u201ccockroach\u201d the size of a shoebox, complete with a flexible, rubber-like antenna. Several flex sensors measure how much the antenna bends as it moves against a wall. A computer program translates the information into distance data, which the robot, just like its six-legged inspiration, uses to judge and adjust how far it is from a wall. In addition to medical applications, their research, which landed on the May 2006 cover of The Journal of Experimental Biology<\/em>, may help in developing better robotic navigation in collapsed buildings, caves, and various emergency situations.<\/p>\n

\"The<\/a>
The South American knifefish emits electricity that enables it to \u201csee\u201d in the dark and helps researchers understand human locomotion.<\/strong><\/figcaption><\/figure>\n

Thanks to the electricity emitted from the small, South American knifefish, Cowan and Eric Fortune, assistant professor of psychological and brain sciences in the Krieger School of Arts and Sciences, are shedding new light on the complexities of human locomotion. Though the two professors are next-door neighbors in north Baltimore, neither knew the other\u2019s area of expertise until 2004 when Cowan asked Fortune\u2019s daughter what her father did at Hopkins. \u201cShe told me that he poked fish brains, and my eyes lit up,\u201d says Cowan. \u201cEric wasn\u2019t applying mechanical analysis, but doing cutting-edge neurobiology with the fish [to study the neural basis and evolution of behavior]. It was like peanut butter and chocolate. Neither of us could have done this alone.\u201d<\/p>\n

Just four hours after Cowan first visited Fortune\u2019s lab, the duo had the pilot data for their first successful grant from the National Science Foundation. \u201cThe knifefish\u2019s ribbon fin can generate a force that moves it forward and backward in a line,\u201d Cowan explains of their experiments in which they place the fish in an open-ended tube and move the tube back and forth. \u201cThe fish swims its fins off to stay in the tube.\u201d<\/p>\n

Using its eyes and sensory cues from the weak electric signal the nocturnal fish uses to \u201csee\u201d in the dark, the fish instinctively measures velocity and makes the necessary speed adjustments to remain in the tube. The team\u2019s engineering analyses demonstrate, for the first time, that Newton\u2019s laws of motion are hard-wired in the fish\u2019s brain\u2014a discovery that has broader implications for all animals. \u201cBy examining the sensory processing systems of a diversity of animals, we begin to see that every animal has to move mass through space and make continual adjustments using sensory feedback from all over the body,\u201d Cowan says of their discovery, which was published in the January 31, 2007, issue of The Journal of Neuroscience<\/em>. \u201cUnderstanding how the brain processes this overwhelming amount of information is crucial if we want to help people overcome pathologies.\u201d<\/p>\n

To dream big,<\/strong> professor Andreas Andreou \u201986 thinks small. Very, very small. Two years ago, he and his research team in the Whiting School\u2019s Department of Electrical and Computer Engineering (ECE) began work on a silicon cortex using nanoscale 3-D silicon on insulator complementary metal oxide semiconductor (SOI-CMOS) technology. Roughly 4,000 times thinner than the human-hair-width 2-D microchips used in today\u2019s computers, this new technology allows Andreou to stack multiple chips to enable the design of highly interconnected circuitry that comes closer to the brain\u2019s neural hardware than ever before. The silicon cortex chip could potentially be used to overcome brain injuries and degeneration and to augment electronic interfaces to advanced prostheses.<\/p>\n

\u201cThe brain isn\u2019t a super computer,\u201d explains Andreou, who received his PhD in 1986 from Hopkins before joining the Whiting School faculty almost two decades ago. \u201cIt\u2019s an incredible network with the computing occurring directly in the network. One of the challenges in engineering silicon brains is that the cortex has enormous connectivity that, until recently, we couldn\u2019t replicate in silicon.\u201d Using SOI-CMOS technology to create a silicon retina and cochlea, combined with his research in speech and language processing (he co-founded the school\u2019s Center for Speech and Language Processing with retired ECE professor Moise Goldstein), inspired Andreou\u2019s next leap. \u201cThe 3-D silicon technology allows us to go beyond the limits that appear on the horizon of technology,\u201d he says. \u201cNow we can think about making a silicon brain that will have true cognitive abilities.\u201d<\/p>\n

\"These<\/a>
These 3-D silicon chips developed by professor Andreas Andreou replicate the brain\u2019s neural hardware.<\/strong><\/figcaption><\/figure>\n

The way we perceive the world is through our eyes, ears, and skin. If we could augment cognition with a silicon cortex, why not? There are a few times I wish I had more brain power,\u201d he says.<\/p>\n

After testing and tinkering with their first prototype, Andreou\u2019s team synthesized the second generation 3-D silicon cortex chip, which is currently being manufactured. \u201cLike babies, these chips come out in nine months,\u201d he jokes.<\/p>\n

The 3-D silicon cortex chip complements other research in his lab. Electrical and computer engineering PhD student Miriam Alderstein Marwick has used CMOS technology to design a silicon photoreceptor that can detect single photons and hence can see in the dark, just like rods in the retina. According to Andreou, its performance is comparable and even exceeds that of biological systems.<\/p>\n

\u201cWhen I started my career, we said that we\u2019d never be able to make a silicon brain,\u201d notes Andreou, who in 2005 was named an Institute of Electrical and Electronics Engineers (IEEE) Fellow for his groundbreaking work in energy efficient sensory microsystems. \u201cI was scared at first when we started developing the silicon cortex, but what is humanity? We need to have an open mind.\u201d<\/p>\n\"JHU-ENG-MAG-SR07-121\"<\/a>\n

Molecules\/Cells<\/span><\/h1>\n

\u201cWe have the technology.<\/strong> We can make him better than he was. Better… stronger… faster.\u201d Marc Ostermeier can recite verbatim the iconic catchphrase from Six Million Dollar Man<\/em>, the 1970s TV show he watched as a kid about an astronaut-cum-cyborg-cum-government operative.<\/p>\n

Today, as an associate professor of chemical and biomolecular engineering at the Whiting School, Ostermeier doesn\u2019t engineer high-tech arms, legs, eyes, or ears like the scientists on the TV show. Instead, he focuses on the fundamentals.<\/p>\n

\u201cProteins are the molecule that nature chose to carry out the widest variety of functions,\u201d Ostermeier explains. Some of the body\u2019s thousands of proteins act as switches, enabling cells to respond to complex signals. In 2004, he and his research team discovered how to successfully join two unrelated proteins to engineer a protein switch, which can be cued to turn on and off.<\/p>\n

\"By<\/a>
By creating protein \u201cswitches,\u201d researchers are creating cells that respond to complex signals\u2014 technology that could advance cancer treatment.<\/strong><\/figcaption><\/figure>\n

The therapeutic possibilities of repeatable cell-to-cell communication are far-reaching. One example is chemotherapy, which eradicates cancer cells\u2014but also poisons healthy cells. \u201cBy engineering a protein to be a switch that would bond to a chemo drug and only recognize something on a cancer cell as its release trigger, chemotherapy could be selectively administered to cancer cells only,\u201d says Ostermeier. \u201cThis is the kind of application we are shooting for.\u201d Disease detection is another desired end product of the research in the Ostermeier lab. His team is working on creating a switch that would light up fluorescently when it senses certain cellular activity, such as certain molecules indicative of cancer.<\/p>\n

Now Ostermeier\u2019s challenge is to make the switches better\u2026stronger. With funding from the National Institutes of Health, National Science Foundation, and the JHU Institute for NanoBioTechnology, his team is perfecting a model to duplicate the complex way nature improves proteins. \u201cHow life works in the end comes down to the molecular level,\u201d he says. \u201cProtein switches are a large part of the reason why we\u2019re more than the sum of our parts.<\/p>\n\"JHU-ENG-MAG-SR07-119\"<\/a>\n

Collagen<\/span><\/h1>\n

Supermodels and Hollywood<\/strong> starlets aren\u2019t the only ones who use collagen. \u201cIf you look at any animal, collagen is the basic framework for any tissue,\u201d says Michael Yu, assistant professor in Materials Science and Engineering. \u201cAlmost 30 percent of our body\u2019s protein is collagen.\u201d This common, non-toxic protein is the workhorse of the human body. It promotes blood clotting, rarely triggers rejection, and its sponge-like scaffolding is essential for cells to grow nerves, bones, and skin. Collagen is also the framework for Yu\u2019s research.<\/p>\n

\"Mimetic<\/a>
Mimetic peptides bind with collagen proteins to create modified collagen that could help prevent the formation of scar tissue.<\/strong><\/figcaption><\/figure>\n

In August 2005, he pioneered a new, easy way to modify collagen by mixing it with minute molecules called collagen mimetic peptides. Prior to this, collagen was altered by cooking it at a high heat or by mixing it with intense chemicals, techniques that can damage the protein itself, as well as cells and other bioactive molecules that co-exist with collagen. Yu\u2019s technique attaches the \u201chitch-hiking\u201d mimetic peptide to collagen, binding it to the collagen\u2019s triple-helix structure. Like any good marriage, the tiny peptide fills in gaps in the collagen\u2019s rope-like configuration. The peptide is loyal, too, attaching only to the collagen.<\/p>\n

In February, Yu received a National Science Foundation Career Award to perfect his technique (see p. 5) and to create biomedical applications for modified collagen, such as using it to thwart the formation of scar tissue. Modified collagen may also help to prevent organ transplant rejection by ramping up blood vessel vascularization\u2014the speed of the process and the proliferation of blood vessels during vascularization are critical to successful transplants. In addition, blood clots in arteries and tumors could be detected through imaging techniques using the collagen mimetic peptides, and a collagen-based bandage could fight infection longer and more effectively.<\/p>\n

He says the ultimate goal, though, is to engineer tissue and create new organs. \u201cRecently we\u2019ve been exploring how our technique could be used to make artificial corneas. If all medical tools fail, the last alternative is to replace an organ. My research begins where medicine\u2019s options typically end.\u201d<\/p>\n\"JHU-ENG-MAG-SR07-117\"<\/a>\n

Eyes<\/span><\/h1>\n

Consider the cornea.<\/strong> As the clear part of the eye\u2019s outer wall, it covers and protects the iris and pupil. As the eye\u2019s camera, it transmits light and refracts images onto the retina, enabling us to see the world around us. Damaged corneas from disease, injury, or infection are the fourth leading cause of blindness in the world. Each year in the United States, an estimated 30,000 corneal transplants are conducted, making the surgery\u2014which involves replacing a disc-shaped segment of the cornea with a similarly shaped piece from a healthy, donated cornea\u2014by far the most common of all transplant operations today.<\/p>\n

Consider the drawbacks, though. Corneal transplants are rejected 5 to 30 percent of the time, and the operation can lead to infection, bleeding, and glaucoma. Then there\u2019s the constant need for donated corneal tissue.<\/p>\n

Jennifer Elisseeff, assistant professor of biomedical engineering, considers this and more as she engineers artificial adhesives for the eye to repair corneal damage and repair and seal the incisions made during cataract procedures. The research team in her Biomaterials and Tissue Engineering Lab at the Whitaker Biomedical Engineering Institute at Johns Hopkins works closely with Oliver Schein, the Burton E. Grossman Professor of Ophthalmology at Hopkins Wilmer Eye Institute. Eventually, their collaborative research may lead to artificial corneas that could be used in transplants.<\/p>\n

Three years ago, Schein approached Elisseeff about partnering to pioneer materials for the eye to be used in corneal and cataract surgery. \u201cIt\u2019s a new field,\u201d says Elisseeff of their biomaterials, which have just begun animal trials. \u201cThe chemistry is still very synthetic for materials used in the eye today, such as contacts. There is strong potential for incorporating [many] more biological materials into the eye. We try to do novel, innovative strategies.\u201d<\/p>\n

Elisseeff uses hydrogel scaffolds\u2014a 3-D network for cells to rebuild tissue\u2014to engineer artificial corneal tissue that mimics the way real corneal cells divide, differentiate, and proliferate. \u201cGrowing cells is an art,\u201d she says. \u201cThe engineering part is important. You\u2019re tinkering and building tissues that can integrate with the body.\u201d<\/p>\n

\"JHU-ENG-MAG-SR07-116\"<\/a><\/h1>\n

Limbs<\/span><\/h1>\n

Open. Shut. Open. Shut.<\/strong> The shiny, blue robotic replacement hand after Darth Vader whacks off the real one with the whoosh of his light saber fist. An undergraduate student wearing a bonnet-like cap fitted with non-invasive electrodes sits in front of the hand. As he thinks about moving his hand, a computer captures the change in his brainwaves and opens and closes the mechanical hand on command.<\/p>\n

Other robotic hands rest on nearby lab tables, their palms and fingers as graceful and smooth as those of a Greek statue. Unlike their sci-fi counterpart flexing its fingers a few feet away, these hands look human with skin-like cosmesis. The 20-plus student and faculty research team in Nitish Thakor\u2019s Biomedical Instrumentation and Neuroengineering Lab at the Johns Hopkins School of Medicine are working hard to make sure these state-of-theart prosthetics function as human hands, too.<\/p>\n

The hands \u201cfeel\u201d temperature through sensors embedded in the fingertips of the cosmesis. The sensors heat up or cool down depending on the temperature of the object it touches. And thanks to flexible force sensors mounted on the prosthesis, and a shoulder harness providing vibrating haptic and vibrotactile feedback, the hand can also sense how much pressure to apply when picking up a pencil or paper cup or squeezing a ketchup bottle.<\/p>\n

The robotic hands under development represent the next generation of prosthetics: neurally controlled devices that recall brain signals and decode and interpret them in real time. These prototypes are light-years beyond the standard prosthetic hand available today: the Otto Bock hand, a \u201cCaptain Hook-like\u201d device that opens and shuts through EMG electrodes that sit on the skin above an amputee\u2019s muscles. \u201cMost amputees today don\u2019t use their prosthetic limb on a daily basis because the limb is bulky, mechanically heavy, and not aesthetically pleasing,\u201d explains Soumyadipta Acharya, a PhD candidate in Biomedical Engineering and part of Thakor\u2019s research team. \u201cIt\u2019s a grand engineering project to make a limb that is a huge advance over the current prosthetic. This project is revolutionizing the way we control and feel artificial limbs using signals from our brain, nerves, and muscles directly.\u201d<\/p>\n

It\u2019s also helping to kick-start a whole new field, something Thakor knows a thing or two about. Twenty years ago, Thakor, who holds his tenure and conducts research through the Johns Hopkins School of Medicine and teaches in the Whiting School of Engineering, began his Hopkins career working with the implantable defibrillator, or pacemaker, a now-standard cardiac device that was first developed and implanted in a patient at Hopkins. \u201cNow the exciting new frontier is neuro and rehabilitation engineering\u201d exclaims Thakor. \u201cThe idea is to bring technology to solve problems in an innovative manner and to advance science in application for problems in the brain sciences and neurobiological diseases and disorders. We are devising methods to diagnose brain disorders and injuries and developing implantable brain stimulators using brain signals to control prosthetic limbs. These are new territories and an exciting future awaits us.\u201d<\/p>\n

\"The<\/a>
The next generation of prosthetics are neurally controlled, can \u201cfeel\u201d temperature, and sense pressure.<\/strong><\/figcaption><\/figure>\n

In June 2006, his team performed the first, successful demonstration of a brain-controlled prosthetic hand moving individual fingers. Their research is part of Revolutionizing Prosthetics 2009, a program sponsored by the Defense Advanced Research Projects Agency (DARPA) to create a neurally controlled upperlimb prosthetic ready for FDA approval and clinical trials by 2009. Last year, DARPA awarded Hopkins\u2019 Applied Physics Lab (APL) $30.4 million as part of an international consortium of more than 10 organizations committed to bringing better prosthetics to market for people with limb loss as a result of accidents, disease, birth defects, and war.<\/p>\n

Thakor oversees several sub-projects of the APL grant including: skin-like cosmesis; sensors for touch, force and temperature; prosthetic EEG control; and decoding neurons to control individual fingers and dexterous motions of the next-generation prosthetic hand. The Whiting School\u2019s Ralph Etienne-Cummings, an associate professor in the Department of Electrical and Computer Engineering, consults on the central pattern generator (specialized neural circuits that produce rhythmic outputs to control motor systems), and Allison Okamura, an associate professor in Mechanical Engineering, provides the expertise on haptic feedback.<\/p>\n

The Revolutionizing Prosthetics 2009 Program, managed by Stuart Harshbarger at APL, is testing its first limb system. Known as Proto 1, it was used in early clinical investigations with partners at the Rehabilitation Institute of Chicago. It is a significant step forward in naturally-controlled limbs and the perception of sensory interactions.<\/p>\n

This summer, Thakor and his team will begin testing their prototypes with amputees. Vikram Aggarwal, a master\u2019s student in Biomedical Engineering, finds it all a little humbling. \u201cWhen you\u2019re working, you can get lost in the details of the nitty-gritty of the neurons,\u201d he remarks. \u201cBut in the end, this is not just advancing science, it\u2019s improving someone\u2019s quality of life.\u201d<\/p>\n

Thakor agrees. \u201cWhile the challenges of interfacing to the nervous system and decoding its message are huge, the potential for making an impact is equally great. We have the knowledge and the technology is within our reach; we now have to make it work for the benefit of the amputees.\u201d<\/p>\n\"JHU-ENG-MAG-SR07-114\"<\/a>\n

Joints<\/span><\/h1>\n

Jennifer Elisseeff<\/strong> knows what it\u2019s like to walk the halls of a hospital and listen to patients complain about stiff joints and the chronic pain that often accompanies arthritis and other cartilage defects. After all, she spent two years in medical school at Harvard University while pursuing her PhD in biomedical engineering from the Harvard\u2013 MIT Division of Health Sciences and Technology.<\/p>\n

\"Researchers<\/a>
Researchers are making synthetic scaffolds to create cartilage that will bond better to the body\u2019s natural cartilage.<\/strong><\/figcaption><\/figure>\n

In her Biomaterials and Tissue Engineering Lab in the Johns Hopkins Whitaker Biomedical Engineering Institute, she\u2019s developing artificial cartilage for clinical applications, focusing on both form and function. Elisseeff is designing and manipulating a sophisticated synthetic scaffold to create cartilage that will bond better to the body\u2019s natural cartilage and soft tissue. She notes that the current biomaterials used as artificial cartilage have a tendency to not stay in place. \u201cOur research is a combination of applied and basic research,\u201d she explains. \u201cWe look at how bone and cartilage talk with each other. They\u2019ve always communicated with each other, but science hasn\u2019t understood it.\u201d<\/p>\n

To create a better bonding cartilage, she examines adult and embryonic stem cells to see how they rebuild and form tissue. By creating multi-layered hydrogels to serve as scaffolds, Elisseeff and her team are able to mimic the complex, 3-D networks of musculoskeletal tissue\u2014 research that will lead directly to a better understanding of cell behavior and tissue regeneration. This first for the biomaterials field was published in Nature Materials in April.<\/p>\n

All of this, she says, is leading to a groundbreaking end-goal: a minimally invasive, injectable chondral implant to be used mostly with knees. \u201cIt will be used for treating cartilage defects that can lead to arthritis later in life and as an arthritis treatment. Patients want to avoid metal and plastic implants. We\u2019re trying to repair tissue with the same natural material that was lost.\u201d<\/p>\n\"JHU-ENG-MAG-SR07-113\"<\/a>\n

Spinal Cord<\/span><\/h1>\n

In the Department<\/strong> of Electrical and Computer Engineering, Associate Professor Ralph Etienne-Cummings finds inspiration on the path less taken. As a pioneer in the field of neuromorphicengineering, he designs biologically inspired robotics that walk, run, and strut with grace and agility\u2014very much a step in a different direction from the field\u2019s standard of using strict mathematical and control theory to produce less natural robotic movements. \u201cBiological systems have evolved over millions of years and hence should offer very efficient examples of what engineered systems can do,\u201d says Etienne-Cummings. \u201cNo computer can remotely perform tasks routinely performed by some of the simplest living organisms.\u201d<\/p>\n

Etienne-Cummings\u2019 research in sensorymotor integration has led him to examine such humble organisms as the lamprey eel and the housefly. Currently, the common cat is helping his Computational Sensory Motor Systems Lab create new pathways\u2014and new hope\u2014for the treatment of spinal cord injuries. In 2006, his lab, in collaboration with Vivian Mushahwar, of the Department of Biomedical Engineering and Center for Neuroscience at the University of Alberta, Edmondson in Canada, conducted the first-ever, successful experiment with an artificial central pattern generator (CPG) that replicates a neural circuit in the spinal cord in vivo.<\/p>\n

To demonstrate that the silicon version could replace the biological version, they implanted electrodes in a paralyzed cat\u2019s leg muscles. Sensors attached to the cat\u2019s legs fed input to the CPG, which is no larger than a pencil eraser and was designed by Francesco Tenore, a Whiting School PhD student in Electrical Engineering. When activated, the CPG controlled the leg muscles, and the cat walked along a three-meter-long platform. Data reveals that the CPG-generated motor activation patterns are comparable to those produced by its biological counterpart.<\/p>\n

\"Lamprey<\/a>
Lamprey eels and horseflies provide biological inspiration for the treatment of spinal cord injury.<\/strong><\/figcaption><\/figure>\n

For the cat, it may have been small steps. But it\u2019s a giant leap for the growing field of neuromorphic engineering\u2014and one of the first, critical steps in creating a neural prosthesis to restore movement. Spinal cord injuries disrupt the brain-to-muscle cord communication\u2014 and subsequent motor control\u2014but the local circuits in the spine are generally left intact below the lesion. \u201cWe\u2019ve replicated some of the biological circuits on the chip to create the signals that generate locomotion by direct communication with muscles,\u201d Etienne- Cummings explains. \u201cIn the future, the chip will actually communicate with spinal cord\u2019s natural neural circuits that communicate with the muscles.\u201d<\/p>\n

He estimates that a neural prosthetic for spinal cord patients is about a decade away. \u201cThere\u2019s still a lot of work to be done, both at the spinal cord physiology\/anatomy and artificial controls of these systems,\u201d he explains. \u201cWe are developing the next version, an implantable chip that will seamlessly interface with the nervous system to record directly from the spinal cord, process the information, and stimulate the cord directly.\u201d<\/p>\n

\u201cWe\u2019re extracting essential [biological] components and implementing them to reproduce functionality,\u201d says R. Jacob Vogelstein, a Hopkins PhD student in Biomedical Engineering, who works on prosthetics in Etienne-Cummings\u2019 lab. \u201cIt\u2019s a very small miracle, except we know how the miracle works because we built it.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"

In the time it takes to read this sentence, 50,000 cells in your body will die and be replaced with new cells. Lined up end to end, the body\u2019s more than 10 billion nerve cells would stretch 45 miles. Each day, you breathe an average of 23,040 times, and your blood makes its daily 60,000-mile…<\/p>\n","protected":false},"author":4,"featured_media":2532,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[28],"tags":[],"class_list":["post-2508","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-features","issue-summer-2007"],"acf":[],"yoast_head":"\nBody Builders - JHU Engineering Magazine<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/engineering.jhu.edu\/magazine-archive\/2007\/07\/body-builders\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Body Builders - JHU Engineering Magazine\" \/>\n<meta property=\"og:description\" content=\"In the time it takes to read this sentence, 50,000 cells in your body will die and be replaced with new cells. Lined up end to end, the body\u2019s more than 10 billion nerve cells would stretch 45 miles. 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