A brief introduction to this topic.
What are the requirements?
What Exists Now?
What can be done right now?
Cell Press. "Engineers hack cell biology to create 3-D shapes from living tissue." ScienceDaily. ScienceDaily, 28 December 2017. <www.sciencedaily.com/releases/2017/12/171228132039.htm>.
What needs doing now?
Speculations, suggestions, criticisms, etc.