The assurance timeline: Building assurance cases for synthetic biology

Recent research advances in modifying and controlling DNA have created a booming field of biological engineering called synthetic biology. In synthetic biology engineers manipulate and modify living organisms to change (and produce entirely novel) functionality, which has led to new fuel sources or the ability to mitigate pollution. Synthetic biology research is also expected to lead to methods of intelligent drug delivery. In synthetic biology, designs are first built using biological programming languages and then implemented in a laboratory. These synthetic organisms can be considered living programs that will sense, respond and interact with humans while they persist in the natural environment. We argue that we should view these as safety critical devices which can be both regulated and certified. Since the synthetically engineered organisms follow a regular cycle of reproduction and replication that involves mutations, they will eventually adapt and evolve new behavior over time. In this paper we propose the use of an assurance case for synthetically engineered organisms, and present an orthogonal dimension, an assurance timeline, that can be used to reason about the dynamic, evolving aspects of these systems. We present a case study based on a real application to illustrate our ideas.