3D-printed bacterial communities

A new technique for printing microbial communities in three dimensions is revealing how different bacteria work together to fend off antibiotics.

The approach, which could lead to an improved understanding of lung infections in cystic fibrosis patients, involves mixing small numbers of bacteria with a warm gelatin solution. This sets when it cools, trapping individual bacteria within the gel, rather like flies frozen in ice cubes.

Next, a high-precision laser can be used to etch the gelatin, fashioning enclosures of different shapes and arrangements that initially contain individual - or a handful of - bacteria.

It's also possible to lay down sequential layers of gelatin containing different types of microbes to study the interactions between mixed bacterial populations.

The bugs can either be allowed to mix directly, or can be kept physically apart by thin gelatin walls. But because the gelatin is permeable, the microbial communities can send chemical signals to each other and also pick up nutrients, meaning that the bacteria are not harmed and grow rapidly in their newly-fashioned homes doubling their numbers every 30-45 minutes.

According to study author and University of Texas at Austin researcher Jodi Connell and her colleagues, "This versatile fabrication strategy presents a foundation to explore the elaborate mechanisms that allow bacteria to adapt and thrive in complex, heterogeneous environments in nature."

The team go on to conclude, in their paper published in PNAS, "Nesting a bacterial colony within a higher or lower density community, such that it is completely surrounded in three dimensions either by the same or different species, could provide insights into the underlying mechanisms involved in cellular communication and the onset of social behaviors between microbes within proximity to one another..."