Biotechnology is usually a reference to the application of traditionally non-biological sciences to living organisms. As we gain a greater understanding of the human body, the potential for advancement is growing at a tremendous rate. The result is that a field still in its infancy within the memory of most adults is now funded with billions of dollars and employs thousands in research, development, and production for all forms of applications.
Finding a career in biotech requires a good science background. A strong understanding of biology is key, and then a strength in an applied realm (computers, chemistry, physics, robotics...) provides the "technology" element. An interest in helping people is also helpful, for, as is true with most research, the work can be frustrating at times. Having a noble goal helps to get you past the rough times a lot more than a simple paycheck can. On the other hand, biotechnology can pay quite well, if you are successful, so the pay isn't likely to be a source of depression.
Biotech has exploded into far too many areas to list them here, but here are a few examples of projects that people are constantly involved in developing:
Prosthetic limbs constantly make the news (in scientific news sources, at any rate.) Ongoing research seeks to link nerves to computers to provide delicate control over arm and finger movement. Computerized receptors can also relay digital sensations back into the nervous system. While perfection is far from complete, advances are made regularly, and the possibility is there that people who have been dismembered or were born with birth defects may regain (or gain) the full use of their otherwise missing parts. There is also interest in developing body parts superior to a plain flesh and bone limb. A "bionic" arm could provide "super strength" to an individual - a technology of particular interest to the military. To seek a career in prosthetics, you'd be interested in materials (chemistry), mechanics (mechanical engineering), and control (computers and robotics) alongside your biological knowledge.
Synthetic organs are also a goal of biotechnological research. Why wait for a donor, after all, if you can just pick up a new kidney at Radio Shack? I exaggerate, of course, but the premise is clear. As with prosthetic limbs, materials and mechanics are imperative. The control aspects are less involved, as people do not have voluntary control over their organs anyway.
Drug delivery systems are always in demand. I'm reminded of a not-too-old "Plastics make it possible" commercial, which mentions a plastic disc that slowly releases a chemo drug to specifically target a tumor - in his brain! Fans of Star Trek are thrilled that real research has been done to develop actual "hyposprays" as a painless way to inject drugs. Technology allows specialized pills to release an entire dose at once, a steady dose over a period of time, pulses of doses at regular intervals, or a combination of the three. (Eurand Pharmaceutical - http://www.eurand.com - does a lot of work with this technology.) For a career in drug delivery, go with chemistry especially, and perhaps a bit of engineering too.
Medical monitoring systems are growing in popularity. Glucose meters are a hot commodity for diabetics. Pulse meters are built to hook into iPods. Drug test kits can be built small enough to be carried in a wallet, and with the interest in steroid usage, fast drug testing at sporting events could become a common occurance. Again, chemistry and computers are useful here.
Gene sequencing, splicing, and manipulation in general have given rise to GMO's, or genetically modified organisms. While a hot topic for debate, a growing number of jobs are available here. (You just might not want to tell strangers what you do for a living right away.) This technology is deeply rooted in biochemistry, so make sure you have it.
If a career in biotechnology appeals to you, I strongly encourage you to start looking at the work being done, to help you decide where to focus your energies. By no means is it an easy career path, but the rewards for both you and the people who benefit from your work are tremendous. And if you do happen to pursue a future in biotech after reading this article, especially if it had an impact on your decision, I'd love to hear about the work you do (nothing confidential, of course). Good Luck.