Living cells are amazing things. They created the oxygen we breathe and the fossil fuels that power our world. They provided the organic compounds that form the basis of many drugs and materials. They feed us, live in our bodies, and protect us from other cells and viruses. They can self-organize. They can learn.

It's clear, then, that the potential range of what biological systems could do is enormous. Among the areas that could most obviously benefit from them are health care, chemical and materials production, environmental remediation, and energy. However, most of the systems that would be useful in these areas are unlikely to occur naturally. We probably won't stumble upon a cell capable of serving as an artificial blood substitute, for example, or one that harnesses sunlight as transportation fuel. These systems must be engineered.