Scientists have developed bacteria that serve as mobile pharmaceutical factories, both producing disease-fighting substances and delivering the potentially life-saving cargo to diseased areas of the body.
They reported on this new candidate for treating diseases ranging from food poisoning to cancer — termed “bacterial dirigibles” — at the 241st National Meeting & Exposition of the American Chemical Society.
“We’re building a platform that could allow bacterial dirigibles to be the next-generation disease fighters,” said study leader William E. Bentley, Ph.D. “The concept is unique.”
Bentley explained that traditional genetic engineering reprograms bacteria so that they produce antibiotics, insulin, and other medicines and materials. The bacteria grow in nutrient solutions in enormous stainless steel vats in factories. They release antibiotics or insulin into vats, and technicians harvest the medicine for processing and eventual use in people.
The bacterial dirigible approach takes bioengineering a step further. Scientists genetically modify bacteria to produce a medicine or another disease-fighting substance. Then, however, they give the bacteria a biochemical delivery address, which is the locale of the disease. Swallowed or injected into the body, the bacteria travel to the diseased tissue and start producing substances to fight the disease.
Bentley chose the term “bacterial dirigibles” because the modified bacteria actually have the fat-cigar look of blimps and zeppelins, those famous airships of yesteryear. In addition, the bacteria seem to float like a blimp as they make deliveries.
The prototype bacterial dirigible is a strain of E. coli that Bentley and colleagues developed at the University of Maryland in College Park, where he is Robert E. Fischell Distinguished Professor and Chair of the Fischell Department of Bioengineering.
“We have created a genetic circuit that endows E. coli with targeting, sensing and switching capabilities,” Bentley explained. “The resultant cell is a bacterial dirigible — a cell that autonomously navigates and carries or deploys important ‘cargo’.”
The “targeting” molecule is attached to the outer surface of the bacteria. It gives the bacteria an ability to “hone in” on specific cells and attach to them — in this instance, the intestinal cells where other strains of E. coli cause food poisoning symptoms. Inside the bacteria is a gene segment that acts as “nanofactory.” It uses the bacteria’s natural cellular machinery to make drugs, such as those that can fight bacterial infections, viruses, and cancer.