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+ By Beryl Lieff Benderly
+ Illustration by Nola Lopez
+ Illustration by Nola Lopez COVER STORY

Extra Strength

Engineering offers new insights into diseases and tools to treat them.


Three thousand years ago, an Egyptian fashioned a piece of wood into what archaeologists believe is the earliest known medical device: a prosthesis to replace a missing big toe. The impulse to find technological solutions to health problems continues to this day. For centuries, physicians dominated the effort. In recent decades, however, the explosive growth of many technologies has burst the boundaries of old disciplines, bringing engineers into collaboration with medical researchers and practitioners and giving rise to a field known – often interchangeably – as bio-engineering or biomedical engineering.

Artificial joints, heart pacemakers, kidney dialysis, heart-lung machines, and magnetic resonance imaging (MRI) are only a sampling of the major advances in diagnosis and treatment that this alliance produced in the 20th century. In the 21st, propelled in part by the addition of the Institute of Biomedical Imaging and Bioengineering (NIBIB) to the National Institutes of Health, research is pointing the way to greater advances.

The fourth-millennium prosthetic limb, now under development, is brain controlled. Joints, bones, and cartilage could actually be regenerated using a host’s own cells; heart disease and other ailments will be detected and treated earlier, thanks to more sophisticated imaging, microscopy, and screening; damaged organs may be repaired using cells grown in vitro; and robotics will make surgery more precise and less invasive.

An estimated 16,000 to 32,000 bioengineers are now at work, and the future demand for engineers specifically trained to function at the boundary of biology and technology is likely to grow faster than nearly every other occupation, according to the Bureau of Labor Statistics. But if the career potential is great, the scientific and technological opportunities look even greater, because according to experts, this combination of skills permits the creation not only of new devices and procedures but of whole new approaches to thinking about the human body. And beyond that, the field offers new ways of thinking about engineering and engineers.

An Advanced Look at Cancer

Bioengineering brings “the structure and rigor and the analytical and organizational tools that pervade engineering” into partnership with medicine, says Nicholas Jones, dean of the Whiting School of Engineering at Johns Hopkins University. In doing so, he says, it provides “ways to start not only solving problems that have existed in medicine but actually to define the problems in a different way.”

As an example, Jones cites an NIBIB research initiative on the physics of cancer, which opens up questions and possibilities rarely addressed before. “There’s more to killing this beast than what we’ve been considering,” he says. Historically, cancer research has concentrated on methods to identify cells and destroy them with chemicals and radiation. Researchers are now exploring the physics behind one of the disease’s basic and most deadly features: the process of metastasis, or the ability of cancer cells to spread to new organs and regions of the body. “How do cells detach?” Jones continues. “What are the physical forces or the physical environment that leads to detachment? . . . . How are [cells] transported through the vascular system? How do they land? What . . . . causes them to physically attach? If you’re an engineer, you want to understand fundamentally how that process works. Once we understand that, we will be ready to figure out how to make it not work.”

A similar engineering-based approach can illuminate processes behind other diseases, says Robert Linsenmeier, professor of biomedical engineering, neurobiology, and physiology at Northwestern University. Fluid dynamics, for example, can help explain “why atherosclerosis hits certain places in the blood vessels, as opposed to other places. That’s using engineering to solve biological questions.” Linsenmeier points out that development of the common prosthetic, the interocular lens, required understanding oxygen transport for the cornea. His own research seeks to grasp the mechanisms of retinal diseases and employs a combination of microelectrode recording techniques and mathematical modeling.

Thanks to such 21st-century advances as the completion of the human genome project and development of nanotechnology, bioengineering is poised for exciting breakthroughs, says Jennifer West, chair of bioengineering at Rice University, whose research involves the synthesis, development, and application of novel biofunctional materials. “The field is driving toward more work at the cellular and molecular levels,” she says. “All of these [advances] are enabling us to really use engineering strategies and design principles.”

Left: Dr. Jennifer West, right, oversees the work of graduate student Melissa McHale in her laboratory for biofunctional materials at Rice University. Middle: A higher magnification of similar microbeads with bEnd.3 microvascular endothelial cells stained for nuclei (blue) and actin (red). The bead particles can be seen as a gray haze. RIGHT: MHP36 murine neural stem cells encapsulated in polymer microbeads and stained for visibility.

Left: Dr. Jennifer West, right, oversees the work of graduate student Melissa McHale in her laboratory for biofunctional materials at Rice University. Middle: A higher magnification of similar microbeads with bEnd.3 microvascular endothelial cells stained for nuclei (blue) and actin (red). The bead particles can be seen as a gray haze. RIGHT: MHP36 murine neural stem cells encapsulated in polymer microbeads and stained for visibility.

Biomedical engineering’s hybrid roots were planted in the late 19th and early 20th centuries with such achievements as physicist Wilhelm Roentgen’s 1895 discovery of X-rays. By the 1940s and 1950s, interest in biomedical questions among a small but growing number of scientists and engineers led to pioneering conferences and organizations. NIH began to show serious interest in the 1960s, and the Biomedical Engineering Society was formed in 1968. Over the years, various universities developed programs that combined elements of engineering, physical sciences, and biomedical sciences but that generally lacked consistency in content and structure.

The formation of the Whitaker Foundation following the 1975 death of engineer and industrialist Uncas A.Whitaker provided the major impetus for the consolidation of bioengineering as a research field, an academic discipline, and a profession. From the beginning, the foundation focused on supporting and fostering biomedical engineering. Starting in 1995, it gave large institutional grants to found university departments around the country. By the time it ceased operations in 2006, Whitaker had awarded more than $700 million and paved the way for a rapid and significant expansion of the field. Given the growing numbers of students graduating in recent years with bachelor’s, master’s, and doctoral degrees, experts foresee even greater growth in the range and number of the new technologies that will be produced. (The statistics appear in Databytes, Page 20.)

every field of Medicine

The 10-year-old NIBIB seeks to make a similar impact. “Unlike many other NIH institutes, the NIBIB’s mission is not limited to a single disease or group of illnesses; rather, it spans the entire spectrum,” states Director Roderic I. Pettigrew on NIBIB’s website. “We work with doctors from every field of medicine and bring together teams of scientists and engineers from many different backgrounds to develop innovative approaches to health care.” Pettigrew’s own career encapsulates the mission: A physician who also holds a Ph.D. in physics, he was previously an Emory University professor of radiology medicine and bioengineering professor at Georgia Institute of Technology.

Stainless steel microneedles can facilitate transdermal drug delivery [Georgia Tech Photo: Gary Meek].
Stainless steel microneedles can facilitate transdermal drug delivery
[Georgia Tech Photo: Gary Meek].

With a budget of $316 million in fiscal year 2010, NIBIB supports a number of diverse fields, including improved diagnostic techniques; light-based technologies for the study, diagnosis, and treatment of disease; tissue engineering aimed at promoting growth of skin on burn victims, restoring vision in damaged eyes, and creating new organs for transplant patients; and drug delivery devices, including micro needles for painless delivery of drugs, ultrasonic energy to enhance drug uptake, and implantable products to release drugs as needed.

MIT’s Sangeeta Bhatia hopes to grow liver tissue [Courtesy Sangeeta Bhatia].
MIT’s Sangeeta Bhatia hopes to grow liver tissue [Courtesy Sangeeta Bhatia].

The possibilities that researchers envision go even further. For example, Robert Sah, director of the Cartilage Tissue Engineering Lab at the University of California-San Diego, is studying the biomechanics of cartilage with a view to improved replacements for arthritic joints. His team has grown tissue that, like the body’s own cartilage, has cells that produce natural lubricant. Paul Yager, acting chair of bioengineering at the University of Washington, is working on small, portable devices that doctors can use for rapid detection of pathogens in the challenging circumstances that prevail in many developing countries. Darrell Irvine, the Eugene Bell Associate Professor of Tissue Engineering at the Massachusetts Institute of Technology, is developing materials that can boost the immune system’s ability to find and attack cancer cells or pathogens. Sangeeta Bhatia, director of MIT’s Laboratory for Multiscale Regenerative Technologies and professor of health sciences and engineering and electrical engineering and computer science, is using micro- and nanotechnology to overcome the obstacles to growing liver tissues for liver transplants. At Case Western Reserve University, a multidisciplinary team drawn from biomedical engineering, biology, and medicine reported finding a way to regulate heartbeats using lasers. Other engineers, such as Northwestern’s Linsenmeier, concentrate on developing fundamental information about diseases that helps others working on these new medical devices.

Beyond academic research, “another thing about our discipline is that there’s been a lot of entrepreneurship,” says West. “I think that builds the connection – the idea of things we do in the lab going to treat patients. Frequently, you see things going into clinical trials.” Jones notes that today, engineers and physicians, clinicians, and medical researchers are defining problems “in a different way, and from a different perspective, because there are more disciplines at the table. That’s generating a huge amount of excitement,” he adds, “because it’s making people think about these challenges in a different way”. And, he predicts, in moving forward along some of those new paths, “we will witness in the next decade great breakthroughs in fields like cancer and others that people probably could not have even conceived.”

a challenge for Educators

Equipping students to apply engineering principles to biology and integrate biology into engineering requires a demanding and diverse curriculum. West points out that at Rice, the bioengineering undergraduate degree “requires more courses than any other degree on campus – 136 hours.” But even that is only the beginning of a practitioner’s education. Linsenmeier and David W. Gatchell, professor of biomedical science, engineering, and biomedical engineering at Illinois Institute of Technology, state in a chapter of Career Development in Bioengineering and Biotechnology that the knowledge base of a bioengineer can’t be specified completely because there are many subspecialties and “the required knowledge changes as the understanding of biology and the ability to manipulate living organisms in a predictable way improve.” Universities attempt to lay the foundations for this broad knowledge base with a combination of courses that teach students both engineering and biology, fields that traditionally have represented quite divergent outlooks, concepts, and content.

Yet, in integrating into their studies a great deal of diverse material, bioengineering programs cannot simply draw upon the course offerings of biology and traditional engineering departments. A subject like physiology must be taught differently to future bioengineers than to future physicians or nurses, Linsenmeier says. And aspiring bioengineers need to understand different areas of physical sciences from would-be civil engineers. “You’re not thinking about bridges; you’re thinking about arms,” he explains. You’re thinking about things “that bend in different ways, that react differently depending on which direction you put the forces.” Unlike steel, “your bones are very fragile if you twist them, but they’re very good if you just had them in compaction. So standing up, bouncing up and down is not a big thing, but if you twist your leg, it’s more likely to break.”

“You’re not thinking about bridges; you’re thinking about arms.” Robert Linsenmeier, Professor of Biomedical Engineering, Neurobiology, and Physiology at Northwestern University



For that reason, Linsenmeier continues, most programs have shifted to teaching engineering principles within the context of how they apply to human physical problems. Adds West: “Ten to 15 years ago, the programs all looked quite different from each other. Some of them were essentially biology programs with a little bit of engineering . . . . Some of them were a straight kind of chemical or mechanical with biology classes.” Since then, curricula have become much more consistent, she says, although “different departments have a little more of an electrical engineering, mechanical engineering, or chemical engineering flavor, based on who designed the curriculum.”

In an indication of the curriculum’s breadth, six engineering societies cooperated in developing the ABET evaluation criteria, with the Biomedical Engineering Society taking the lead. Graduates, they decided, need to have an understanding of biology and physiology; to be capable of applying advanced mathematics, science, and engineering to solve problems at the interface of engineering and biology; and to be prepared “to make measurements on, and interpret data from, living systems” while addressing problems “associated with the interaction between living and non-living materials and systems.”

While ABET calls for “breadth and depth,” achieving both isn’t easy.

The very diversity of knowledge that is the bioengineer’s strength can also be a weakness, according to James Tien, dean of engineering at the University of Miami in Florida and cohost of a February 2010 joint meeting of the National Academy of Engineering and the Institute of Medicine entitled “Engineering Innovations in Healthcare.” Biomedical engineering, he says, is an “interdisciplinary field” and an “application area” rather than an engineering discipline in the same sense as traditional specialties, such as civil, chemical, and electrical. “You have to learn a lot across several fields. We can’t get you the depth . . . in four years’ time.” For those seeking to work as engineers, Tien advises majoring in a basic engineering discipline and then applying it to biomedical issues. “I think there’s a lot of opportunity for anybody who is interested in these applications,” he says. “Supposing you major in electrical for your undergraduate; it’s very easy at the master’s level then to pick up the [biology] and be as effective as anybody.”

For Linsenmeier, though, “that’s the old-school approach that we’ve been trying to counteract” – the belief, he says, “that in biomedical engineering you get a smattering of coursework [but] don’t develop depth in any particular thing.” Still, he concedes, “there is certainly some truth to it. Most biomedical engineering graduates cannot go out and compete for design-oriented jobs like electrical or mechanical engineers [can].”

Yet, because they are situated at the extremely complex intersections of biology and technology and of healthcare and tech professions, biomedical engineers possess strengths that those trained more deeply in a traditional engineering discipline generally lack. “The breadth that they have is an extremely valuable set of abilities,” Linsenmeier says. It includes “an ability to go across the different engineering fields, talk with the doctors, [and] be very good at talking across teams. They’re very good at going out into the field and learning the needs of doctors, communicating with them. Inside companies, they’re very good for systems engineering, quality control, regulatory affairs, and all sorts of things.” As a result, “the medical device industries are realizing that they can fill certain niches better than other kinds of engineers.”

Tien agrees that there’s a great demand for bioengineers, “mostly in the kind of area that assists medical professionals,” even though “they don’t have enough education to be the leader.” This means that in industrial or product development settings, in order to understand clinical or administrative needs and to conceptualize a solution, biomedical engineers often work closely with the health professionals who ultimately will be the ones putting a future device or procedure to use. The bioengineer then communicates those needs to design engineers trained in one or more of the traditional engineering disciplines.

And, Tien adds, bioengineering has a highly desirable feature: “It attracts a lot of women.” At Miami and other bioengineering programs across the country, undergraduate enrollment is approximately half female, beating the “bad rap” engineering generally has with women, that it’s not helping people, Tien says. West agrees that the goal of contributing motivates many women. Several students have told her that they want to feel that the work they do will help people. “And while I think all engineering disciplines can do that,” she says, “it’s more apparent to the students how that happens in biomedical engineering.”

Most biomedical engineering departments are less than 15 years old and carry “a lot less of the historical baggage,” including a record of male dominance, than more traditional engineering disciplines, West says. And since their faculty members have come to the profession more recently than those in most other disciplines, they offer an added attraction: youth.

 

Beryl Lieff Benderly is a freelance writer based in Washington, D.C.

 

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