[Balgair]

One way I have seen is to have a cadre of scientific/medical advisors with skin in the game (usually, on the board). This is also one of the paths out of debt for MDs that don't want to practice or MD/PhDs in general. With a few people that actually know the science/art, you can then focus on the finance and other issues.

The science part isn't always hardcore mol-bio, as many devices can be a bit more like traditional engineering (even internal ones). But many of the problems that the various agencies will cite will be mol-bio related. Even as a hardcore investor, unless you have the many years of background, or can get people with background to put their own money in it, you are going to have a hard time. Paying just for consulting isn't likely to be appropriate due-diligence. Biology is monstrously complex and frustrating even in one individual, let alone a population. As such, it takes a lot of research to have a good clue of what is going on, more so that you can likely pay consultants for.

EDIT: Again, I want to stress that every situation is different and that I am only relating my personal experiences here.