The Nanoparticles
The nanoparticles are made out of gelatin. This kind of nanoparticles has been shown to be able to transport proteins, organic molecules or DNA. They were biotinylated using activated biotin. We invite you to read more about Nanoparticles. To assemble the nanoparticles with the bacteria, they only need to be in the same tube, because the interaction between biotin and streptavidin is very strong and spontaneous.
Cell surface display
To make the bacteria express streptavidin on their surface, we engineered a plasmid that encodes a fusion protein between streptavidin and ice nucleation protein from pseudomonas syringae, which serves as an anchor for the streptavidin to the outer membrane. Read more about Cell Surface Display . At this point the bacteria would be able to transport nanoparticles, but on its own this wouldn’t make any sense.
Sensing
The crucial point of our project is that E.coli was genetically engineered to sense a specific trigger in the environment. Read more about Sensing. Sensing such a trigger induces the production of enzymes that degrade the nanoparticles, GelE gelatinase from Enterococcus Fecalis and Matrix Metalloprotease MMP2 from H. Sapiens. So the drug will be released exactly where it is needed to treat the patient.