Cell-free production of bacteriophages

Viruses help combat antibiotic-resistant bacteria

"Bacteriophages offer an enormous potential for the highly effective, personalized therapy of infectious bacterial diseases," observes Gil Westmeyer, Professor of Neurobiological Engineering at the Technical University of Munich (TUM) and Director of the Institute for Synthetic Biomedicine at Helmholtz Munich. "However, in the past, it wasn't possible to produce bacteriophages in a targeted, reproducible, safe and efficient manner – although these are exactly the decisive criteria for the successful production of pharmaceuticals."

Now the research team has developed a new controlled production method to create bacteriophages for therapeutic use. The basis for this technology was established by a group of students at TUM and Ludwig Maximilian University of Munich (LMU), who earned an award in the 2018 International Genetically Engineered Machine competition (iGEM). This group then gave rise to the spin-off Invitris, which is currently developing a platform technology for phage-based medications.

The cornerstone of the new technology, which is already in the patent application process and is now being used in new research at TUM, is a special nutrient solution in which the bacteriophages form and reproduce. The nutrient solution consists of an E. coli extract and contains no viable cells; this is a fundamental difference from previous bacteriophage production methods, which traditionally used cell cultures with potentially infectious strains of bacteria.

In the TUM labs, the Munich team has now been able to demonstrate targeted production of bacteriophages in the cell-free nutrient solution: The only component needed is the genome – the plain DNA – of the desired viruses. The genome contains the entire blueprint for the formation of the bacteriophages. When the DNA is injected into the nutrient solution containing the molecular components and enzymes of the E. coli bacterium, the proteins assemble according to the blueprint: Thousands of identical copies are generated in just a few seconds. "This production method is not only fast and efficient, but it's also very clean – the process eliminates contamination by bacterial toxins or other bacteriophages, which are a possible complications in cell cultures," says Westmeyer.