Training the microbe (Day 111)

Training the microbe (Day 111)

15th September 2014

One of the most active groups is IChemE's Biochemical Engineering Special Interest Groups. Sharing best practice, supporting young professionals and generally promoting the discipline are all part of their work, which includes events on topics like synthetic biology and multi-disciplinary meetings for young researchers.

If you've ever wondered about the scale of potential for biotechnology, one of IChemE's past presidents, Ian Shott, leads a new innovation centre for industrial biotechnology in Scotland - called IBioIC.

Estimates suggest  the global market for industrial biotechnology will be worth £150bn-360bn by 2025, of which $4bn-12bn will be in the UK.

This branch of chemical engineering is capable of some remarkable breakthroughs, especially in the healthcare sector.

A few weeks ago, researchers announced they had managed to deploy engineered microbes to specific parts of the body to kill tumor cells or deliver drugs. They had successfully targeted bacteria to particular surfaces and tissues by modifying sticky proteins on the microbes’ surfaces.

The international research team include Luis Ángel Fernández of the Spanish National Center for Biotechnology, and Matthew Chang, associate professor, Department of Biochemistry, at the National University of Singapore (NUS).

The researchers explored the idea of making bacteria seek out certain other cells by engineering the microbes to display antibodies on their surface.

Unfortunately, getting the cells to deliver antibodies to their surfaces proved difficult until they began using adhesins, proteins that naturally coat the surface of bacteria.

The adhesins contain an antibody-like moiety that targets antigens on other cells, facilitating biofilm formation, cell invasion, and other pathogenic activities.

Fernández realised that he could potentially swap out the natural antibody-like domain for another that is specific to a molecule of choice, allowing him to target bacteria to particular biological surfaces.

As part of their test, the researchers built a synthetic adhesin with an antibody that binds to green fluorescent protein (GFP). They incorporated the new adhesin’s gene into the chromosome of E. coli, along with a gene for a bioluminescent protein to help detect the bacteria. The team also deleted the genes for three natural adhesins to reduce nonspecific binding.

The bacteria’s targets were human cancer cells that the researchers modified to express GFP on their surfaces. After mixing the human and bacterial cells together, the team inspected the cells with fluorescence imaging and found that the bacteria colonized the cancer cells. Bacteria without the synthetic adhesin did not adhere to the human cells.

This approach gives rise to an array of applications according to Chang. However, they still need to demonstrate safety and that the bacteria can be engineered to target real-world cancer cell proteins. We wish them well.