Dead microbes keep replicating DNA, paving way for engineered biomaterials

A team from Aarhus University demonstrated that bacterial cells remain capable of DNA synthesis after they can no longer divide, coining the term “zombie bacteria” for the effect. This observation challenges the traditional belief that DNA replication stops as soon as a cell dies.

In lab tests, the researchers exposed typical bacterial strains to deadly chemicals and tracked the subsequent intracellular activity. By employing fluorescent tags that attach to freshly produced nucleic acids, they detected a surge of DNA production lasting several hours beyond the point at which conventional viability tests declared the cells dead. Their results show that the enzymes needed to polymerize nucleotides can stay functional even when the cell’s general metabolism has ceased.

Importantly, the group identified a way to dictate which genetic codes the dead cells generate. Providing synthetic DNA templates together with the bacterial cultures enabled the zombie bacteria to construct specific strands of genetic material. Such precise control hints that inert microbes might serve as miniature, self‑contained production units for bespoke nucleic‑acid products, eliminating concerns about uncontrolled proliferation.

The potential ramifications reach beyond fundamental microbiology. Should the technique be scaled up, it could facilitate the fabrication of innovative biomaterials—like programmable hydrogels or biodegradable scaffolds—built from within by these inert yet chemically active cells. Since the method avoids living organisms, it may bypass numerous regulatory and safety obstacles tied to genetically engineered microbes.

Although the work remains preliminary, the authors warn that additional investigation is required to delineate the boundaries of post‑mortem DNA synthesis and to avert accidental environmental discharge. Upcoming research will probably examine a wider array of bacterial species, evaluate the durability of the synthesized DNA, and explore ways to merge the method with current synthetic‑biology workflows. If these efforts succeed, the “zombie bacteria” system could become another valuable addition to the expanding suite of bio‑fabrication tools.