Biomedical Engineering Health Article

Definition

Biomedical engineering, also known as bioengineering, is the application of engineering principles to the study of medical and biological problems. The goal of biomedical engineering is to use electrical, chemical, and mechanical engineering principles to conduct studies and develop tools that can aid in the biomedical care of patients.

In 1997, the National Institutes of Health issued the following expansive definition of biomedical engineering/bioengineering: "Bioengineering integrates physical, chemical, or mathematical sciences and engineering principles for the study of biology, medicine, behavior, or health. It advances fundamental concepts, creates knowledge from the molecular to the organ systems levels, and develops innovative biologics, materials, implants, devices, and informatics approaches for the prevention, diagnosis, and treatment of disease, for patient rehabilitation, and for improving health."

Description

Biomedical engineering can trace its history to as far back as a hundred years ago, when the first x-ray machines and electrocardiographs dramatically illustrated how technology could be applied towards the diagnosis of disease. Today, the field of biomedical engineering is in full flower, propelled by the momentum of the post-World War II technology boom and the latest molecular, genetic, and computational developments. Having gone beyond its roots in imaging and instrumentation, biomedical engineering now encompasses at least 13 specialties, according to the 2000 edition of The Biomedical Engineering Handbook.

These specialties include

• biomechanics
• prosthetic devices and artificial organs
• transport phenomena
• biomaterials
• biomedical instrumentation
• biosensors
• medical and biologic analysis
• medical imaging
• physiologic modeling, simulation, and control
• biotechnology
• rehabilitation engineering
• clinical engineering
• medical informatics

Biomechanics, prosthetic devices and artificial organs, and transport phenomena

Biomechanics is the application of classical mechanics (the study of how objects move in response to forces placed on them) to biomedical problems. Classical mechanics provides general principles for understanding (for example) how fluids move, how objects become deformed under various forces, and how levers and forces move objects. Biomechanics uses these principles to understand how blood moves throughout the body, how injuries affect the shape and mechanics of body parts, and the mechanics of body movement (e.g. how an arm is lifted, or how a person walks). Biomechanics has contributed to an understanding of the mechanical function of the bones, cartilage, and soft tissue in the musculoskeletal system, as well as an understanding of other major organ systems, such as the heart, lungs, and blood vessels. Some of the technologies coming from biomechanics include artificial hearts and heart valves, and artificial joints such as prosthetic hip and knee replacements. These types of technologies have spawned another specialty in biomedical engineering, prosthetic devices and artificial organs. Another closely affiliated specialty is transport phenomena. This subfield concerns itself with the processes of fluid flow and heat transfer in biological systems.

Biomaterials

Biomaterials are living and artificial materials that can be used in implantation. Whereas biomechanics focuses on the mechanical design of an implant, biomaterials science focuses on the body's biochemical interactions with the material from which an implant is made. A biomaterial for an implant should be chemically inert, non-toxic, and non-carcinogenic. It should also be resilient enough to endure a lifetime of chemical and mechanical forces. Biomedical engineers in the specialty of biomaterials test and study materials possibly suited for implantation. Biomaterials science has contributed to the use and understanding of currently used implant materials, such as ceramics, polymers, metal alloys, and composite materials. Biomaterials science is also leading research into the use of living tissue as implant material with the goal of minimizing implant rejection and simulating the body's original biomechanical environment.

Biomedical instrumentation, biosensors, medical and biologic analysis

Biomedical instrumentation, or bioinstrumentation, uses mechanical, electrical, and optical principles and systems to monitor the body's physiologic status. Many of the physiologic changes that occur in the body are mediated by electrical signals. Different ions (charged elements or molecules) are allowed to flow into and out of cells at different times, depending on cellular and systemic demands. Biomedical instrumentation attempts to infer aspects of the body's physiologic state by measuring and interpreting these electrical signals. Optical systems are used to measure the variable of interest indirectly; for example, because hemoglobin—the molecule that carries oxygen in the blood—changes its light absorptiveness according to whether it is attached to oxygen, changes in the oxygenation of blood can be inferred from the optical properties of blood and tissue.

The specialty of biosensors focuses on the development and instrumentation of measurement systems. Technologies emerging from biomedical instrumentation generally, and biosensors specifically, include electrocardiographs (ECGs) and pulse oximeters that measure blood oxygenation. The associated specialty of medical and biologic analysis seeks to refine current understanding of the biomedical signals received by the instruments. It attempts to discern and amplify the signals of interest while diminishing noise and unrelated signals. In addition to biomedical measurement, the specialty of biomedical instrumentation includes the development of devices to control and guide biomedical processes through mechanical or electrical means, e.g., cardiac pacemakers and respirators.