The phrase ‘engineers make a difference’ is used in virtually every branch of engineering, and no doubt the structural, civil, chemical and other engineers would all argue that they make the biggest difference of all. But there is one branch of engineering that has a direct affect on our lives that the other disciplines cannot. Biomedical engineering helps to relieve pain, repair damage, improve the quality of life, deliver faster, non-invasive diagnoses – and more.

Colin Hunsley, who chairs the Medical Engineering Division of the UK’s Institution of Mechanical Engineers (IMechE), outlines the wide-ranging subject areas in which biomedical engineers work: “I started my career as a design engineer working on neonatal products – incubators, feeding devices, and so on – but today’s graduate engineers could find themselves involved in areas that would have been restricted to pipe dreams in those days, such as robot-assisted and laser surgery. Imaging is a very important area now, with CT (computed tomography) and MRI (magnetic resonance imaging) scans allowing clinicians to see what is happening to a patient almost in real time; similarly, monitoring devices like pulse oximeters – that measure the level of oxygen in the blood by means of a device in contact with the patient’s finger – are a good example of a relatively simple concept that engineers have succeeded in turning into cost-effective, user-friendly products.

“The development of prosthetics requires significant engineering effort, whether we are talking about hip, knee or ankle joints, stents or artificial limbs for reconstructive work following joint wear, an accident or to combat cancer. There is also continuous investment in the development of medical devices, with inhalers being a recent example.”

While the temptation is always to use engineering to solve technological problems, Colin Hunsley firmly believes that responsible biomedical engineers must be

market-led. With an ageing population, there is therefore an emphasis on products that will meet the requirements of this particular market.

“Hearing aids, products to assist blind or partially sighted people, and devices to help elderly people remain self-sufficient in their own homes are all important. There is also a growing need to address diseases that tend to afflict the elderly, such as osteoarthritis.”

Patient interface focus

Regardless of the branch of biomedical engineering, one of the biggest challenges is the patient interface. Colin Hunsley explains: “For a routine hip replacement, the surgeon will select modular components to build up a joint that will suit the patient. However, for some reconstructive surgery there may be a requirement to use rapid prototyping technologies to create prosthetics that are unique to the patient. We also have to be aware of biocompatibility, as the human body can be a harsh environment for many engineering materials; and, conversely, the body will reject most materials. Various surface treatments have been developed to help overcome this, but the latest developments seek to go beyond a material or device being merely tolerated by the body; rather the aim now is to create something that will function with the human body as well as – if not better than – what it replaces.”

The patient interface is also just as important for products that will be used by patients, clinicians and carers, which includes inhalers, needlefree devices for mass vaccination (Fig. 1), diagnostic instruments and aids for use by the elderly and infirm at home. Likewise, computer-controlled, robot-assisted surgery relies on a good interface with the patient.

While it is of the utmost importance in biomedical engineering, a successful user interface is not a requirement that is unique to this discipline. Similarly, most of the other challenging aspects of biomedical engineering have parallels in other fields. Tribology is one such example; tribology is critical for implants, as friction must be controlled and wear particles are highly undesirable. Another example is product testing, where the scope for an exhaustive test regime is restricted, but the same is true for, say, space projects and civil engineering. And while biomedical products and systems have to conform to strict regulations – so as to CE mark a medical device, for example – there is a requirement to work to a given brief in all fields of engineering.

Nevertheless, the strict regulatory procedures that must be adhered to in biomedical engineering can be frustrating and feel like a barrier to innovation, even though engineers in this field are often working at the leading edge of technology. Colin Hunsley says: “Anything new has to be shown to be better than what is currently available. A modern hip replacement, for example, is expected to last for 15 years or more; even with thorough testing via the formal clinical trials process, it can be hard to prove conclusively that a new development is significantly better. The take-up of new products and techniques also depends to some extent on the way the market operates. In the UK, for instance, the National Health Service (NHS) funds most healthcare, whereas the USA market is driven by private medical insurance. With the budgeting structure of the NHS, it can be difficult to justify the adoption in one department of a more expensive treatment, even if it could lead to significant long-term savings for another department. This illustrates why it is important that biomedical engineers understand the market in which they operate.

“Furthermore, a new product or technique may produce excellent results when used by the surgeon who developed it, but outcomes may not be easily repeatable.”

Intellectual property

While the market and regulatory climate can constrain innovation, care has to be taken to ensure that intellectual property is captured and enables progress to be made. Medical and pharmaceutical companies are typically very cautious about revealing any details of new technologies unless they are appropriately covered by patents. And because so many patents are filed, there is a great deal of cross-licensing to help keep development programmes moving forwards. It is therefore important to manage the intellectual property as an integral part of the product development in order to capture the true value of the project.

A substantial body of research and development is currently underway in universities, commercial organisations and providers of healthcare (such as the UK’s NHS). Colin Hunsley believes that a number of new technologies will come to the market in the near future: “One trend we will see is a greater use of surgery that is less invasive, with less material being removed from the patient and less being put back in. As these techniques are developed, there will be a greater use of simulators for the training of surgeons and the planning of operations. I also have high hopes for greater use of tissue engineering, in which new parts of the body – cartilage, for example – are grown outside the body before being implanted. Nanotechnology also has the potential to make important contributions to niche applications, mainly in the field of sensors and diagnostics, where complete systems can be built on a chip.”

Clearly there will be an ongoing demand for biomedical engineers. However, Colin Hunsley feels that a better grounding can be gained from more traditional engineering courses: “My personal view is that it is best to take a broad-based engineering degree first, then follow that with a Masters degree that provides the specialist biomedical knowledge and skills. And while some people may have always wanted to work in biomedical engineering, others may find that it is a mistake to lock themselves down from the very start of a university degree course.”

But for those who do pursue a career in biomedical engineering, there are many types of employer, ranging from small and medium-sized enterprises to large multinational companies, and engineers often have the opportunity to work at the leading edge of technologies.