This article focuses on bioengineering practices that is one of today’s most exciting and rapidly growing fields of engineering. The field of bioengineering was developed primarily in the latter half of the 20th century, although its roots can be traced back to the work of early scientists such as Galileo and Newton. Another characteristic of the 20th century was the Age of Specialization. We now have come to a point where creative contributions and major advances are made at the interface and the cross section of fields. Bioengineering provides a fantastic model for such an interface. Computational bioengineering is proceeding from the genetic level to the organic. The major advances in biology, such as the field of genomics, have created a tremendously fertile ground for discovery and application. Engineering methods and principles have a vast opportunity to make an impact. There is a need to develop experimentally based computational models and tools to address problems ranging from regulation of gene expression to subcellular and cellular interactions, to tissue and organ function. This is a field at the intersection of biotechnology and information technology.
Bioengineering is one of today's most exciting and rapidly growing fields of engineering. The field as we now it was developed primarily in the latter half of the 20th century, although its roots can be traced back to the work of early scientists such as Galileo and Newton. The 20th century was known as the Century of Physics. The 21st century is beleived to be the Century of Biology. Bioengineering is a field that connects physical sciences to biological sciences, making it a bridge between the two centuries and, as such, one of the major fields of engineering of the 21st century.
Another characteristic of the 20th century was the Age of Specialization. We now have come to a point where creative contributions and major advances are made at the interface and the cross section of fields. Bioengineering provides a fantastic model for such an interface. During the last decade, the field has grown at a rapid pace. The fact that bioengineering attracts some of the brightest young minds in colleges of engineering signifies that it is a field of the future.
The definition of bioengineering can be broad, but its key characteristics are the application of engineering principles to the study of biological sciences and biological systems. In addition, it includes various traditional fields of science: physics, chemistry, mathematics, and computing. Engineering is defined by the National Science Foundation as a field that “creates, integrates, and applies knowledge across ever-changing disciplines to create shared wealth, protect and restore the environment, and improve societal well-being and the quality of life.” Bioengineering is an engineering discipline that has broken into the frontiers of biological disciplines.
The field has evolved from its early years, when engineering principles and technologies were applied, adapted, or devised for biological systems, to modern bioengineering, which involves the integration of engineering principles and technologies with cellular and molecular biology.
The general mission of bioengineering can be said to be the development of sciences and technologies that influence our health through avenues such as diagnosis of diseases, surgical and therapeutic interventions in healing, and sensing and monitoring methods to help with critical condition and management of chronic diseases. The ultimate goal is to maintain and restore quality of life.
Sold Rastegar is a program director at the National Science Foundation’s Division of Bioengineering and Environmental Systems. He is currently on leave from Texas A&M University in College Station, where he serves on the biomedical engineering faculty.
It is a formidable task to list all of the contributions of this field within the scope of one article, so we will focus on some of the bioengineering contributions that have their roots in mechanical engineering.
In doing so, we will only make a roll call of the great advances that have been accomplished in other fields.
On the diagnostics side in the field of medical imaging there have been tremendous advances—from X-ray, to MRI, to ultrasound, to optical and fused imaging methods, as well as several methods currently under development. On the sensing and instrumentation side, designers have invented and developed a myriad of electronic and optically based devices, which are an in dispensable part of diagnostic instruments in hospitals throughout the world. On the therapeutic side, cardiac pacemakers are the marvels that have made an incredible impact on the lives of millions of people.
Total joint replacement was one of the most significant technological contributions of biomechanical engineering during the last century, and it makes a tremendous impact on the quality and length of life. Scores of individuals are being assisted by knee and hip replacement surgeries every year. Through engineering innovations, materials development, and computational optimizations, these artificial joints have evolved to the point that they can last from 15 years to more than two decades. As a result of technologically advanced procedures, debilitating and sometimes lethal orthopedic conditions have been transformed to normal and manageable life conditions.
Artificial internal organ programs, especially those for the heart and the kidney, started in the 1960s, along with the space program, during the Kennedy administration. As a result, major contributions have been made to the field. While a total artificial heart has not yet been realized as a common tool, major advances toward it have been made by a number of scientists and through the sacrifice of daring volunteers. On the other hand, left ventricular assist devices, heart valves, large-diameter synthetic vascular grafts, and artificial heart pumps are all part of the artillery the cardiovascular surgeon may implement in combating and managing heart disease. Other tools used in cardiovascular systems include balloon angioplasty, laser catheters, and catheter-based ultrasonic evaluation of the vasculature. It is noteworthy that artificial kidney technology has not had major advancements since a program at the National Institutes of Health was stopped, indicating that there are many areas of need for which government funding is critical to advancement for a variety of reasons, including lack of potential for near-term commercial exploitation.
In the area of bioheat transfer a number of advances were made 1 during the last century. At the extreme of freezing, the fields of cryobiology and cryosurgery have come to maturation. We have gone from freezing the first red blood cell, which had an unbelievable influence in control of the blood supply, to recent advances in cryopreservation of insulin-producing pancreatic islet cells and preservation of rare plant species. Cryosurgical treatment of prostatic diseases is among the other noteworthy contributions.
On the physiological temperature range, great contributions on the nature of heat exchange in the human body have been made by theoretical models of the interaction of the bloodstream and tissue.
At the extreme of high temperatures, as well, models and tools have been developed for understanding and application of thermally based devices using energy sources that vary from radio frequency to microwave to ultrasound to lasers. Still on the horizon is the full exploitation of photonic transport within biological tissue for diagnostic, sensing, and therapeutic ends.
Tissue engineering, still in its early development stage, is one of the most exciting fields of bioengineering. The term “tissue engineering” was coined in the late 1980s to describe the science of converting isolated cells into functioning tissues.
A key technological component of tissue engineering involves the design and synthesis of the polymer matrices, or scaffolds, that form the initial structural support of these cell composites. The term “tissue engineering” has grown to encompass the use of these polymers for other medical applications, such as gene and drug delivery and basic studies of the cellular interactions and communications within the matrices.
Early high-risk investments by the National Science Foundation in this field have resulted in exciting developments, through the recent establishment of an engineering research center and additional centers of excellence supported by other funding agencies. Tissue engineering is an example of a field in which the potential for commercial exploitation may not be immediate but where great potential for impact on health and commercial benefits are bound to manifest themselves in the long term.
The axiomatic development of the field is germane to the past, present, and future of bioengineering developments and contributions. The foundations of modern biomechanical engineering and the science of biomechanics were set through the pioneering work of the likes of Richard Skalak, H.R. Lissner, and Y.C. Fung. Fung is known as the father of biomechanics.
The invaluable contributions of these early pioneers have set a firm foundation on which to build not only mechanical-based bioengineering but also to set a systematic model for other fields of bioengineering to follow.
Biomechanics is a field in which the scientific and engineering developments are not mere application of existing mechanics laws. In fact, new constitutive laws have had to and will need to be developed to describe the total complexity of biological organisms. One of the key challenges ahead is to address and develop methods that logically and axiomatically connect the hierarchy of biological systems—organs to tissues to cells to biomolecules. Bioengineers have the opportunity to influence the control and understanding of biological processes in the same way that chemical engineers influenced control and understanding of chemical processes in the 20th century.
Bioengineering and biotechnology have been enjoying financial support from federal agencies and private foundations.
At the National Science Foundation, support of bioengineering dates back to the 1960s, when special projects in various programs were written by visionary investigators, who received awards from visionary program directors. In the early ’80s, a formal program was formed, and in the ’90s the Division of Bioengineering and Environmental Systems was established.
Bioengineering is also supported throughout the Engineering Directorate as well as by other directorates of the foundation. Eight Engineering Research Centers, which account for about one-third of all such centers supported by the NSF, have been established in various universities with a focus on bioengineering.
The foundation also recently awarded the money for a Science and Technology Center in nanobiotechnology.
As funds to establish and support the Engineering Research Centers are awarded through a highly competitive, unsolicited process, one realizes that a major part of current interest in engineering is in bioengineering. A review of the subject area of these centers alone can give a sense of the pulse of the current activities and future outcome in bioengineering. The bioengineering-based Engineering Research Centers consist of one each in bioengineered materials, bioprocess engineering, engineering of living tissue, computer integrated surgical systems, neuro-morphic systems, biofilm engineering, and marine bioproducts engineering. An additional grant was recently awarded for an Engineering Research Center devoted to bioengineering education technology.
There has been support of engineering and bioengineering at the National Institutes of Health for many years through its various institutes. There was a new movement, starting in the early 1990s, which led to the formation of the Bioengineering Consortium, or Becon, in 1997. It awarded its first grants in 1999. Becon is now in its second year of offering opportunities for focused bioengineering grants as well as bioengineering partnership programs. These technology-based grant opportunities are a departure from the traditional NIH disease-based and hypothesis-based grants and offer a new culture at NIH as well as new possibilities to benefit the public.
From the private sector, a few single large contributions have been made by famous industry donors to individual institutions. With the economic boom in place, it is expected that more of these types of donations will occur.
One of the key private supporters of bioengineering has been the Whitaker Foundation, whose primary mission has been to support the field of biomedical engineering through a peer-review grant process. In addition to the support of young investigators through startup competitive grants, the foundation has given substantial infrastructural grants to several major universities, which have accelerated their efforts in bioengineering. The foundation has been instrumental in bringing formalism and visibility to bioengineering units at these universities.
While the benefits of applying engineering principles and technology to improving the quality of life cannot be disputed, support from the federal government in many aspects of bioengineering could be detrimental to its growth. In the case of tissue engineering, while a number of industries are actively influencing the field, the full commercial potential may be further in the future. It is prudent to support the field because potential benefits to man.
On the Horizon
The most exciting and promising contributions of bioengineering are only on the horizon. There are several exciting areas that are being explored. The following are among the ones that are most stimulating.
Cellular and tissue engineering is fast moving from vision to reality. The early work on tissue engineering has already led to engineered skin and cartilage tissues derived from one’s own cells, and engineered tendon and ligament tissues are in the offmg. Exciting initiatives are also under way into the engineering of blood vessels, bone, and other tissues. Early work has begun on engineering internal organs such as the liver. This last area remains a true challenge of the field.
Furthermore, there is considerable evidence that biomechanical factors play an important role in the regulation of cellular activity, both in normal tissues and in engineered tissue replacements. Similarly, mechanical influences are implicated in the pathologies and etiologies of many diseases. To address these function-related issues there is a need for more research into the mechanical aspects of tissue engineering.
One of the most exciting advances in research has been the recent focus on studying phenomena at the nanoscale level. The nanometer range provides for an exciting dimension in which we are close to the atomic level and yet form, morphology, and structure have macroscopic manifestation and meaning. Biological systems provide for a rich arena in which such phenomena can have great effect.
For example, DNA molecules are about 2.5 nm wide. Cellular nanoscale machines powered by chemical energy of the cell are marvelous new discoveries that provide highly efficient motors, whose applications are yet to be imagined. Other applications of nanobiotechnology are the development of ingenious hybrid materials that incorporate biomolecules and serve unique functions, such as providing new possibilities for smaller electronics. The possibilities are immense and the field is wide open.
Computational bioengineering is proceeding from the genetic level to the organic. The major advances in biology, such as the field of genomics, have created a tremendously fertile ground for discovery and application. Engineering methods and principles have a vast opportunity to make an impact. One of the respected leaders in biology, Leroy Hood, recommends the recognition of a new field, quantitative systems biology.
There is a need to develop experimentally based computational models and tools to address problems ranging from regulation of gene expression to subcellular and cellular interactions, to tissue and organ function. This is a field at the intersection of biotechnology and information technology. Engineers have a long tradition in systemization, analysis, and management of large systems and should be able to make significant contributions.
The promise and the opportunities await us.