Biomedical engineering is a discipline that combines principles and practices of engineering design and component manufacture with biology and medicine. The goal of biomedical engineering is to design and construct devices that, outside the body, aid in the diagnosis and monitoring of normal and abnormal conditions, and, inside the body, replace defective components. Just a few of many examples include the artificial heart, artificial prostheses (e.g., arms and legs), magnetic resonance imaging (MRI) scanners, heart monitors, pacemakers, lenses, rate-controllable pumps, and dialysis equipment.
The advent of the discipline of nanotechnology has spurred research on biomedical engineering at the molecular scale. As an example, research is ongoing that aims to develop robotic probes, which are purely abiotic or that incorporate living material, and which are smaller than a human cell in size; such probes could be injected into the body to act as monitoring devices or even as tiny repair factories, enabling nano-scale surgery from within the body.
Biomedical engineering has its roots at the beginning of the twentieth century, with the development of technologies in medical diagnostics and imaging, such as x-ray imaging and the electrocardiogram (EKG), which measures the pattern of electrical charges in the heart. In the 1930s, scientists invented a human-sized pressurized tank dubbed the “iron lung” to pump air mechanically in and out of the lungs of victims of respiratory paralysis. In the same decade, the heart-lung machine was invented, which could redirect blood out of a patient, allowing the heart to be stopped for surgery. Other milestones of note were the use of artificial tissue replacements in 1954 and the invention of the pacemaker in 1955.
Engineers have employed biomedical engineering for decades in the design and manufacture of medical devices. A regulatory system of device categorization and approval exists in countries including the United States. The U.S. Food and Drug Administration (FDA) employs a three-class regulatory system. Class I devices are simple in design and pose little if any risk. Examples of class I devices include elastic bandages, surgical gloves, and hand-held instruments. Class II devices are more complex and are generally not used inside the body, such as wheelchairs, x-ray machines, and MRI scanners. Class III devices require stringent assessment prior to approval for use, and often operate inside the body. Replacement body components and implanted pacemakers are examples of class III devices.
The development of biomedical engineering has been in parallel with regulatory initiatives such as the three-class system summarized above, which seek to guarantee the proper performance of the particular device and its safety to recipients. Government regulations for approval and oversight of biomedical engineering vary from country to country. In the United States, the federal government wields most of the legislative power regarding device approval and use, whereas in the European Union more latitude is granted to the attending doctor concerning device use.
As the discipline of biomedical engineering has grown, more universities are offering degree courses. Many universities award a BME degree (Biomedical Engineering) at the masters or doctoral level, for which graduates receive intensive training in engineering, medicine, and biology.
One aspect of biomedical engineering is the replacement of defective or missing external and internal body parts. Artificial limbs are a well-known example. One technology being refined in limb replacement is the linking of the artificial limb to the recipient’s nervous system, which causes the limb to move in response to electrical signals from the brain. The composition of the replacement limb has also been refined: An example is the blade-like carbon fiber artificial limbs worn by former South African sprinter Oscar Pistorius (1986–). Although there was controversy concerning the possible advantage evoked by the design of the limbs to the sprinting stride of Pistorius, (who was dubbed Blade Runner), he competed in the 400-meter dash and relay during the 2012 Summer Olympics in London.
In addition, biomedical engineering has been successful in developing components that are implanted in the body as replacements. The challenge in the implants is greater than external devices, because the devices must mimic the actual body component to avoid stimulating the body’s immune-related defenses. Growth of cells on the surface of devices, which essentially masks the inert material from the body’s immune surveillance, has been successful. Strategies currently being explored include the use of stem cells to develop actual replacement material (e.g., growth of new bone, neurons, or specific organs).
Biomedical engineering can also involve bioinformatics, in which scientists develop computational tools to collect and analyze biological data; the use of biomaterials (materials that are compatible with biological systems); biophotonics (the use of light, often laser light, as a sensing system or to acquire an image of biological systems); and genomics (the study of the genetic material of organisms). Increasingly, biomedical engineering is becoming molecular in scale; this can involve computer simulations of the structure and behavior of biological systems or the use of nanotechnology to construct devices that are molecular in size.