Tissue engineering, which occupies the fertile area between materials science and biology, has its roots in cell biology, immunology, chemistry and bioengineering, but it's not uncommon to see apparently unrelated fields thrown together. Glenn Booma, a director of 'outcomes research' at Genzyme Tissue Repair, in Cambridge, Massachusetts, cites a laser-optics physicist joining a team of physiologists working on a process for solidifying an injected substance by photoactivation.

A working knowledge of more than one branch of science could be very helpful. A postgraduate education is necessary for most research jobs, although a bachelor's degree may suffice in technical support roles. Equally important is an ability to work and communicate with people from other fields, and to keep a global perspective even when concentrating on the details of a project. In a company environment the ability to shift gears rapidly is also a must. If a project turns out not to work, or if a competitor files a patent, says Booma, "then the company is going to want to rapidly reassign you to something new".

Your fate is out of your hands
Nancy Parenteau, chief scientific officer at Organogenesis, a company making wound-repair products in Canton, Massachusetts, says that the cross-fertilization between disciplines is part of the fun. "You should be able to pick up some of the other specialty's language, appreciate their issues and how they go about doing things." The hardest thing for scientists to come to grips with, she says, is that a project does not depend solely on any individual's work, even if it's an outstanding achievement. "In a way, your fate is no longer in your own hands. That can be difficult to become comfortable with."

Non-scientific factors can impinge on careers in a small company. Booma says that none who saw the seminal paper on cartilage defects in rabbits in 1984 would have dreamed it would take until 1997 to get approval from the Food and Drug Administration and commercialize their Carticel product. Now, however, investors do know, so even small companies with impressive technology platforms and good intellectual property may be bought up, as his company was in 1994 when, as Biosurface Technology, it joined Genzyme. "Genzyme and Organogenesis have shown that tissue-engineering products are effective and marketable, but now we have to show that they can be profitable," he says.

Those contemplating a career in tissue engineering should also be politically aware. Positive public attitudes translate into public support, whereas a negative impression can mean restrictive legislation, loss of funding and, in extreme cases, physical attacks on labs and personnel. Scientists should engage in discussion and clarify issues. Parenteau deplores the speculation that occasionally appears in the media as being harmful to the field and misleading and frightening to the public. Even preliminary or limited results can be misinterpreted, raising false expectations for many and confusing the few for whom a breakthrough will truly bring help. "The companies themselves, which have to go out and raise money in order to survive, have a need to play up the bright side and not dwell unduly on the limitations," Booma adds.

New university training programmes and faculty positions and public funding initiatives are good news for hiring trends. In the United States, the National Institute of Standards and Technology's Advanced Technology Program has funded product development in tissue engineering for the past two years with grants of $2–5 million. Last year the NIH set up a tissue-engineering working group, and may set up an institute. Says Gail Naughton, president of Advanced Tissue Sciences in La Jolla, California, "Tissue engineering used not to fit into any single category, but now the agencies are actually out there soliciting grant proposals. This is making a big difference." She foresees career opportunities at various levels.

With growing institutional support, the outlook for the next 10 to 15 years is rosy. Improvements in technique and understanding will speed up progress. For example, Naughton thinks that the question of embryonic stem cells will be obviated by improvements in separations and culturing. "Our growing understanding of how to keep cells functioning outside the body will allow us to manipulate them so that they can become almost any cell type," she predicts, citing recent publications (for example, see Jackson, K.A. et al. Proc. Natl. Acad. Sci. USA 96, 14483; 1999) showing that human cells collected from bone marrow can be transformed into fat, bone or cartilage cells.

Parenteau worries about speculative media coverage, but agrees that what's true now for skin products will probably become reality for vascular, neurological, bone, tendon and corneal tissue. The immunological barrier is a major challenge, but inroads are being made. For example, the Boston company Diacrin has worked out how to mask animal cells so that they can be transplanted into humans; a product made from porcine neural cells to treat Parkinson's disease is in phase II trials. A decade ago neural regeneration at trauma sites was thought impossible. Today it is known that, if scarring is kept at bay, neural tissue has a great capacity to regenerate.

The role of genetics will also increase as tissue engineering is combined with gene therapy to enhance the growth of implanted tissue. The discoveries of genomics will affect the field, such as the as-yet unknown signals that differentiate between normal growth and healing. "Especially in a young field the opportunities are broad and abundant. It is exciting to participate in a field that is being born. Few of us get to do that," says Parenteau.