Bacterial colonies as a living, adaptable photonic crystalThursday (22.03.2018) 09:40 - 10:00 Part of:
Bacterial colonies can exhibit bright and brilliant colouration through the way they organise. When the bacteria stack in a highly ordered fashion, their 300-400 nm rod-shaped bodies form a so-called 2D photonic crystal that exhibits strong light interaction and give colour to these otherwise transparent, slightly yellow cells. In this talk, I will first explain how light interacts with the cell colonies to give this appearance, and afterwards explain some of the important prerequisites for the colonies to form. Such prerequisites include gliding motility and cell-shape. Afterwards, the talk will continue on how the colony organisation can be altered via external physical stimuli and genetic manipulation. This includes alteration of cell shape, motility and change of growing conditions, nutrients and environment. These experiments lead to many interesting observation such as the recovery of colour in a colony where it has been lost; the ability to grow colonies with colours ranging from blue to red; and colony interaction at a distance. The findings shed light on the biological function of the tight colony organisation. Furthermore, we also find that this a highly adaptable natural photonic system that can find applications both within sensing and nanotemplating.