Question: Is synthetic biology going to cure cancer, save the planet from global warming, and replace machines with cells capable of advanced computation?
Answer. Absolutely not.
So why are we being inundated by such predictions from both media and government agencies. Why is such hype allowed to spin out of control?
This is probably because scientists refuse to talk about the limits of synthetic biology. It turns out that if you try and do anything too extreme to a cell, the cell dies. This is why you may be able to squeeze a drop of biofuel out of some bacteria but to produce anything in usable quantities is near impossible. With respect to harnessing the power of cell metabolism for advanced computation, individual genetic circuits can be created, but only a few can be connected together before the cell begins to act in a chaotic manner. This isnt to say such work shouldnt be funded, some of these "toy systems" are both elegant and clever, worthy of being labelled as fantastic science.
I forsee some nice developments in drug synthesis and biosensor technology, but these developments could all be carried out by non synthetic biology routes, probably quicker and faster. Besides these advances would occur without the "synthetic biology" spin if the less sexy genetic engineering description would have been left alone.
Where synthetic biology really does come into is own is in the field of artificial life and artificial biological molecules. Combined with directed evolution, in my opinion, this is the real synthetic biology. It might not have immediate obvious applications but synthetic biology in this form can revolutionise knowledge and advance civilisation. However the time frame for such advances could be on the order of decades. We will all have to be very patient.