Combating COVID-19 with Cell-Free Expression

Imagine the ability to rewire, reshape, and use parts of a living system to build something new. It is not science fiction, nor is it Frankenstein’s monster. It is synthetic biology, a relatively nascent field that is making a profound impact on society and healthcare. As the world continues to grapple with the ongoing effects of the COVID-19 pandemic, researchers are turning to synthetic biology, and in particular, to cell-free expression systems to develop new rapid diagnostic tools, vaccines, and treatments.

“It’s a way to program information. We all do that every day in our cell phones; we program information in zeros and ones. Synthetic biology takes that to a totally new dimension. Rather than just being able to control information, I now get to control information that builds atoms,” said Michael Jewett, a professor of chemical and biological engineering at Northwestern University.

Synthetic biologists such as Jewett combine engineering principles, computer programming, and molecular biology to design and build synthetic gene circuits and other molecular components that rewire living cells for a variety of new applications, including biological sensors and diagnostic tests. 

Going Cell-Free

Rewiring a living system is tricky. Cells are already biologically programmed to achieve their own functional goals, not the goals of the researcher. To circumvent this problem, synthetic biologists remove the cell wall and extract the cell’s molecular machinery, including the core factors needed for transcription and translation. This cell-free expression system can then be coerced to produce and even detect proteins of interest. 

“It’s like if you took a car, you lift up the hood, pull out the engine, and you repurpose it for something else. We’re repurposing the molecular machinery to do some objective function,” said Jewett. Working outside a cellular system prevents the cell from responding and changing its gene expression profile, ensuring a reproducible and stable molecular expression system.  

The Scientist Creative Services Team (Aug 19, 2020). Combating COVID-19 with Cell-Free Expression [Blog post]. Retrieved from