Chemists devise means to use bacteria to encode secret messages

Fluorescence images of BL21(DE3)pLysE fluorescent strains after growth and induced FP expression by IPTG

In the endless search to develop newer and cooler ways to send messages between people without other’s intercepting them, chemists from Tufts University working together have figured out a way to use a strain of bacteria to encode a message on a paper-like material that can then later be de-coded by the receiver. Manuel Palacios and David Walta, along with their team describe in their paper published in the Proceedings of the National Academy of Sciences, how they did it.

Called Steganography by Printed Arrays of Microbes (SPAM), the process is pretty simple. The team first developed seven different strains of the E. coli bacteria that grow in different colors (when bathed in ultraviolet light). They then devised a simple coding scheme based on pairings of the colors to represent letters of the alphabet (and some symbols). Next, they applied the bacteria to a plate of agar (a gelatinous substance that serves as food for the bacteria) where they grew into their respective color types. Next, a sheet of a nitrocellulose type material (that looks pretty much like paper) was pressed over the plate of agar, imprinting it with the bacteria. The result was then dried, causing the coloring attribute to disappear, making it ready for possible placement into an envelope for posting. After some time passed, the paper-like material was pressed onto an agar plate and the bacteria grew once again into their coloring, revealing the coded message…… Continue reading Chemists devise means to use bacteria to encode secret messages