We need a trigger - a stimulus that our biofabricators can
detect and respond to quickly - such that we can control the
synthesis of our biomaterial in a set pattern in 3D. Light is
the most obvious candidate, as holography allows us to generate
complex patterns with well defined edges in 3D. After examining
a number of light sensing pathways, we decided to utilise a
native pathway involving YtvA, which is a protein used by B.
subtilis to detect blue light. YtvA triggers a cascade of
interactions, but some way down the chain, a molecule called
sigma B (σB) is produced. This, in turn, boosts the synthesis of
YtvA. We plan to over-express YtvA and use σB as a promoter for
genes which stop movement and produce biomaterial. Therefore,
when the bacteria detect blue light, those genes will turn on,
the bacteria will stop and biomaterial synthesis will begin. To
achieve accurate distribution of our biofabricators, we must
exert fine control over their motility. Bacteria's primary
method of getting about is via flage