Connecting07 has a recent post, Medical Device Design: 10 Things You Need to Know. While I agree with most of it, a few things I didn't like:
#4 Biocompatibility. Any material used in a medical device has to pass a test before human use. Contact and duration. Must be aware from prototype through production. Material must be tested as used--processed and sterilized. Must be tested in final form. Sterilization affects various materials. There are pre-certified materials. This testing is expensive and time-consuming (8 weeks). There are different tests for different types of use depending on contact and duration.
I've posted on biocompatibility testing before, and as I stated then, the time required varies per device, don't assume 8 weeks is the longest it will take.
#5 Know manufacturing methods. Good Manufacturing Practices (GMP). QSR: Quality Systems Regulations. Lot traceabilty, sterilization methods, sterile packaging validation, specialized equipment, clean room manufacturing. Go to a medical device contractor manufacturer to do these things without the overhead.
Based on personal experience I don't agree with the last line, but some people may have had better luck. At one point in the distant past we were paying a contractor $50,000 a month to manufacture experimental devices for us, with the idea being we would have a "virtual" company and only worry about coming up with ideas and paid contractors to do the rest. After much complaining and pushing over a year we finally gave up on the contract manufacturer after their production reached a grand total of two devices a month. It was a complicated device, but after we brought it in-house with one production manager for paperwork and two assemblers, making two devices a day was fairly easy. The contract manufacturer's heart just wasn't in it.
I like the rest of the post, and think overall it is very good, but I will refrain from commenting on each point, just go over there and read it.