Bacteria often get a bad rap – often only being called out in times of illness – but in reality there are some types of bacteria that we could not survive without. Not only does the bacteria in and on us outnumber the total native cells in our body, but the good kinds actually enable us to digest food, have a heathy immune system, and keep our skin free of parasites and infection.
Outside of our egocentric concern, bacteria is also a necessary source in the environment – like making soil nutrients available to plants, bioremediating toxic spills, and forming pretty colorful films around hot springs. The reason that bacteria is so prevalent and diverse is that it is is remarkably efficient at breaking down and renewing important resources essential to many different ecosystems, so it comes as no surprise that scientists are eager to tap into their natural abilities to advance the field of biotechnology.
In March 2014, a bioengineering team at MIT was able to crack the code. Publishing their findings in the scientific journal Nature Materials, they explained how they were able to alter the biofilms of bacteria to latch onto, align, and connect nanowires and other small technology that is difficult to work with.
The team, headed by assistant professor of biological engineering Timothy Lu, was able to program the bacteria to incorporate and form networks of nanomaterials. They did this by replacing the bacterium cell’s ability to naturally produce a necessary protein called CsgA with a bioengineered version that requires the presence of signaling molecules called AHLs. This allows researchers to control the AHL concentration in the environment in order to create or inhibit production and behavior of cells. The new peptides that were added enabled the bacteria to capture nonliving material such as nanowires or quantum dots and incorporate them into their biofilms.
The advantage to this is intelligent mobility at the nanoscale level: the programmed hybrid electrical material can be quickly created, maneuvered and connected simply by controlling the concentration of certain molecules in the bacteria’s environment.
By replacing peptides within the bacteria that require different signaling molecules, the biofilms produced can thus create gold nanowires, form electrically conductive networks, and connect quantum dots. “Ultimately, we hope to emulate how natural systems, like bone, form.” Lu explains the team’s motivation. “No one tells bone what to do, but it generates a material in response to environmental signals.”
But what can scientists create with this adaptive bionic technology? The new hybrid materials have a large range of applications that the team is hoping to further explore – including adaptive solar cells, waste conversion to biofuels, diagnostic tools and self-healing materials.