Cell-free Protein Synthesis

Researchers build a microfluidics system to create proteins without living cells.

Karen Zusi
Dec 31, 2015

Parallel reactor and feeder channels (top), a single pore in the engineered membrane (left), and a diagram illustrating metabolite exchange across the membrane (right)OAK RIDGE NATIONAL LABORATORYResearchers from the Oak Ridge National Laboratory (ORNL) in Tennessee have created an artificial system to synthesize proteins without needing a cell culture. The group published its report last week (December 22) in Small.

The bioreactor uses a reagent mix that combines E. coli cell extract, DNA encoding the gene for a green fluorescent protein, and the necessary metabolites. Instead of a living system, the new protein synthesis machinery uses long serpentine channels made of silicon integrated with an artificial membrane to combine materials between a “reactor” and a “feeder” channel. “This engineered membrane facilitates the exchange of metabolites, energy, and inhibitory species,” the authors wrote in their paper.

The team compared the protein synthesis of its dual-channel bioreactor to a reference mix incubated in microcentrifuge tubes and in single-channel bioreactors. In the microcentrifuge tubes, the reference mix was simply incubated on a shaker until it stopped producing proteins, leveling off at a final protein concentration of 325 μg/mL. In the single-channel system, the protein yield improved by 24 percent. Comparatively, after refining the engineered membrane, the bioreactor produced a protein concentration of 2 mg/mL.

“With this approach, we can produce more protein faster, making our technology ideal for point-of-care use,” study coauthor Scott Retterer of ORNL said in a press release. “The fact it’s cell-free reduces the infrastructure needed to produce the protein and opens the possibility of creating proteins when and where you need them, bypassing the challenge of keeping the proteins cold during shipment and storage.”