By deciphering the complex phenomena occurring within the human body, biomedical researchers are able to devise new therapeutic approaches to manage and treat disease.
Working alongside these researchers, chemical engineers add their unique expertise to turn many of these promising new concepts into reality. The resulting techniques and devices are now being successfully used to help lengthen and improve our lives.
Over the past 50 years many pioneering breakthroughs in kidney dialysis have been made by chemical engineers. Often called artificial kidneys, kidney dialysis machines cleanse the blood of impurities. Since the early 1940s, when the first practical artificial kidney was developed, work has continued to create smaller, more effective, and more affordable dialysis machines.
Cleansing the blood
The first machine used for home hemodialysis, the Milton-Roy Model A, was designed by chemical engineering professor Les Bab in order to help the daughter of a friend. Photo by Jim Curtis. Courtesy Home Dialysis Central.
Kidney dialysis machines represent an excellent example of the life-enhancing synergies that result when chemical engineers join forces with physicians and biomedical researchers. These “artificial kidneys” are essentially mass-transfer devices. They cleanse the blood, removing elevated levels of salts, excess fluids, and metabolic waste products.
The first practical dialysis machine was developed during World War II. Since then many major developments have taken place. One of the major obstacles that had to be overcome, however, was size. To be truly practical a single-patient portable machine was needed.
One of the ten wonders
In 1964 Les Babb, a chemical-biochemical engineer, along with his colleagues at the University of Washington, designed a portable, fail-safe, single-patient dialysis machine. Within five years this stand-alone machine would become the dialysis system of choice throughout the world. In 1990 the Biomedical Engineering Society named this machine one of the “Ten Wonders of Biomedical Engineering.”
The incidence of diabetes is on the rise. To control this chronic disease many patients must test glucose levels in their blood and regularly inject themselves with insulin. Through the combined efforts of chemical engineers, physicians, and biomedical researchers, improved techniques for monitoring blood glucose levels and administering insulin have been developed.
Monitoring and maintaining
Automatic monitoring systems for diabetes care use sensors inserted under the skin and attached directly to portable insulin pumps to provide greater treatment accuracy and convenience. Courtesy Ben Feldman, PhD, Abbott Diabetes Care.
Diabetes is on the rise. As a chronic disease, it places an enormous medical and economic burden on our society.
Patients with diabetes must constantly monitor and maintain their glucose level. This task can be challenging and has life-threatening implications.
Through the combined efforts of the chemical-engineering and biomedical communities, improved techniques for measuring blood glucose levels and administering insulin are being developed.
Glucose level monitoring
Recent innovations include:
- Microanalytical techniques that require smaller blood samples,
- Continuous glucose monitors that are implanted beneath the skin, and
- Use of implanted microchips to control insulin addition.
New advances include:
- Automatic, continuous-infusion insulin injection pumps little larger than a cell phone, and
- Compact pens that combine the insulin container with the syringe.
Tissue engineering involves the use of living cells as building materials. Engineered tissues are being created to repair or replace damaged or diseased organs and tissues. And now some of the functions performed by the human body can be augmented or replicated by this innovative, multidisciplinary technology.
Building with cells
Surgeons are able to make body wall repairs using this biocompatible material developed with the help of chemical engineers. Photo via National Institute of Biomedical Imaging and Bioengineering. Courtesy Stephen Badylak, MD, University of Pittsburgh.
Promising research-and-development activities in tissue engineering involve the creation of biological substitutes used to restore, maintain, and improve tissue function. They may even replace entire human organs. Engineered biological substitutes are currently being developed to repair or replace damaged or diseased organs and tissues. Examples include
- Transplantation cells that perform specific biochemical functions, for example, improving pancreas, liver, or bladder functions;
- Replacement tissues, such as artificial skin, bones, cartilage, blood vessels, tendons, and ligaments; and
- Stem cells able to regenerate functional human tissues.
A growing field
The development of suitable human replacement tissues is still in its infancy. One early success is replacement skin, grown over engineered polymer scaffolds, that is used to treat burn victims. Currently, researchers are pursuing viable techniques to enhance and maintain mammalian stem-cell and neuron functions. Biodegradable polymeric fibers are also being designed to act as nerve-guide conduits in the regeneration of nerves. All these imaginative endeavors require the expertise and technical contributions of chemical engineers working in concert with biomedical researchers.
Historically, the conventional method of delivering medications to patients has been by mouth or injection. Early advancements have included nasal sprays, dermal patches, and controlled-release products. Now, with the help of chemical engineers, targeted drug-delivery vehicles distribute medications directly to the desired location within the body and release it on demand.
Controlled and on target
Micro medical robots, many shaped like little beetles, are designed to travel inside the body in order to treat infected areas and thus minimize the need for surgery. Photo by Yoshikazu Tsuno/Getty Images.
Drugs have traditionally been delivered to patients by mouth or by injection. Working together to increase both the efficacy and safety of drug delivery, chemical and biomedical engineers have devised a variety of improved delivery techniques. These new methods also provide the added benefit of enhanced comfort and convenience for the patient.
Early drug-delivery breakthroughs using chemical principles include:
- Nasal sprays that deliver finely atomized amounts of a drug via inhalation,
- Transdermal patches that deliver controlled doses through the skin, and
- Controlled-release capsules and wafers that deliver drugs over an extended period.
In recent years targeted drug-delivery methods have been an important area for chemical and biomedical engineers. Novel vehicles are being designed that deliver a drug precisely to the targeted organ, tissue, or tumor. The drug payload is then released in response to an internal or external trigger and in the amount required at the site.
Such delivery systems have the advantage of being able to:
- Reduce or delay premature degradation of a drug once it is in the body,
- Maximize the ability of a drug to travel through the body to the target site without affecting healthy tissue and organs,
- Minimize the total amount of the drug that must be administered, and
- Reduce potential side effects that often result when healthy tissue and organs are exposed to a drug.