Our completed machine serves as the first of a chain of events which could be expanded for multiple applications. The ‘Biotweet’ machine enables the movement of bacteria to an attractant (A). Once the source of the attractant is found (IPTG), the bacteria return to the starting position through an attraction towards B, the attraction towards A is switched off at this point. The bacteria that complete this circular journey are the messenger bacteria. Upon returning to the start position, they recruit other bacteria to send them to the site of the attractant to perform a particular function, such as degradation. Important to note is that since the bacteria will return to the start, this means that none will remain in the environment in which they were employed to work. This provides assured safety whilst working with our machine (See our safety page).

Our machine utilizes two riboswitches, one sensitive to theophylline (at A) and the other sensitive to atrazine. The beauty of the use of riboswitches in our project is that they can be substituted with riboswitches sensitive to other substances. This ensures that our machine can be used as a template, where attraction towards virtually any substances can be engineered.

The above template can be employed in the industrial sector to identify and degrade contaminants or alternately to collect substances of economic importance.

Example: Messenger bacteria attracted to a contaminant such as Mercury. Upon finding the Mercury, they will return to the start to recruit a number of bacteria which have the ability to absorb it. Once the Mercury has been absorbed, the transcription of the riboswitch inducing the attraction of the bacteria to the starting position will be activated. The bacteria will then return to the start position (home), leaving the environment free of genetically modified organisms.

There is much room for the improvement of diagnostic technology, where some diagnoses can take months to perform, such as is the case for TB. A riboswitch specific to a disease biomarker can be engineered to allow the bacteria to search a blood sample, or biomarkers at low concentrations present in the saliva or urine. Upon contact with the biomarker, chemotaxis can then be toggled where the bacteria will return to the start position and report on their findings.