Probiotic cream that ramps up heat production could prevent frostbite

In the future, polar explorers and deep-sea divers may use a probiotic cream on their skin to prevent frostbite or hypothermia. This hope arises from a scientific breakthrough where researchers have genetically modified skin-dwelling bacteria to sense temperature and generate additional heat when required, marking a first in this field.

“It’s very creative work. You can imagine this cream being the difference between getting frostbite or not,” comments Harris Wang from Columbia University in New York, who was not part of the study. “I can think of many applications – from keeping warm in winter, preventing frostbite during expeditions, to deep-water diving – where generating heat is important.”

Guillermo Nevot Sánchez at Pompeu Fabra University in Barcelona, along with his team, has genetically altered a strain of the bacterium Cutibacterium acnes, one of the predominant microbes on healthy skin, to produce double the usual amount of heat. This was achieved by employing CRISPR, a genetic editing tool, to modify levels of a protein called arcC that plays a role in energy production.

The researchers also used CRISPR to adjust the expression of heat-sensitive genes in another batch of C. acnes. This modification enabled the microbes to detect temperatures above 32°C (90°F), which they signaled with a fluorescent glow.

According to Nevot Sánchez, these results offer the first evidence that skin bacteria can be engineered to produce additional heat in response to temperature changes. The next step for the team is to integrate these two capabilities into a single bacterium and demonstrate that it can recognize a dangerous drop in temperature, not just elevated temperatures.

Nevot Sánchez mentions that the team has conducted unpublished experiments indicating that C. acnes strains can survive when incorporated into a cream.

“We could develop a probiotic cream that you put over most of the body – before hiking into cold places, for instance – to prevent hypothermia,” says Nevot Sánchez, who shared the research findings at the Synthetic Biology for Health and Sustainability conference in Hinxton, UK, on 12 March. He adds that it could also benefit people living in harsh climates without heating.

However, further research is necessary to determine how effectively such a cream can heat human skin samples in the lab and on mice before proceeding to human trials, Wang notes. Nevot Sánchez emphasizes that developing methods to eliminate the bacteria when desired, perhaps by applying a secondary cream, will be vital to prevent potential side effects like overheating.