Once you accept that it is possible for science to understand the workings of proteins, the basis of cell biology, it ultimately leads you to conclude that things like "immortality" will be indeed be possible. Because the protein-folding and combining processes involved are tedious and difficult to uncover, but they do not defy comprehension. So, yes, this knowledge will be used with ever greater mastery.
Life On Earth has had billions of years to slowly develop winning configurations of folded proteins. But this same sort of evolutionary testing could probably be done on supercomputers at blistering speeds. Also, the rate at which scientists improve their knowledge is measured is in years and decades - not billions of years.
It's not too hard to accept that medicine will soon be able to produce a brand new liver grown from a patient's own stem cells. Kidneys too, Skin? Hearts? Why not? But, the brain? It's a more complicated organ, sure. But, it too, works by processes that can be studied and copied just like the liver.
In the case, of the brain, though - this implies that an augmented, improved or optimized brain would be possible as well. And a network of super brains would also be possible. And Earth covered by trillions of points of super-awareness might be possible. Such an advent would spell the end of human beings as the dominant life-form on the planet; we would become like the horseshoe crabs you see on East Coast beaches - sheer anachronisms, remnants of a life-form that was state-of-the-art a billion years ago.
Blue Brain Project is now attempting to crack the brain's information-processing secrets and finally discover the true source of consciousness. The lead researchers claims that an artificial brain is possible within ten years.
If the mystery of awareness becomes fathomable, and it seems likely that it eventually will be, all bets are off about the future. ...Because now you're talking about the Singularity, the point at which it becomes unimaginable for any of us presently to perceive how events might subsequently evolve. Even our notion of "immortality" may eventually seem hopelessly inadequate when observed from some point in the future. We overlay onto the idea of "immortality" too much of our own preconceived notions about what it is and how it might eventually exist in the world.