'Shaking up' biofilm research: Active topography reduces bacterial infections

For decades, scientists have relied on antibiotics as the primary method of combating bacterial infections. However, a University of Tennessee, Knoxville professor named Dacheng Ren has taken a different approach in his efforts to prevent infections altogether. Ren's innovative strategy involves designing surfaces that actively discourage bacterial adhesion, effectively preventing infections from taking hold in the first place.

Ren's groundbreaking idea emerged from an unexpected discovery made during a routine project with his students. While the initial results of the experiment were not as anticipated, the students' keen attention to detail led to the development of a promising concept. This discovery centered around the observation that bacteria are less likely to form biofilms on surfaces with specific topographical features.

Biofilms, which are layers of bacteria encased in a protective matrix, significantly reduce the susceptibility of bacterial cells to antibiotics. These biofilms pose a major threat as they contribute to medical device-associated infections in patients with catheters, artificial heart valves, orthopedic implants, and other devices. Such infections can lead to severe illness or even death.

Ren's research team has been working on engineering surfaces that bacteria find unappealing, with a focus on the concept of active topography. This involves creating flexible materials that can be manipulated using temperature changes or magnetic activation. The resulting surfaces have proven to be highly effective at preventing biofilm formation and, in some cases, even removing established biofilms up to 99.9%.

One of Ren's most recent innovations is a prototype self-cleaning urinary catheter designed to improve patient comfort and safety. Traditional medical devices often use static materials, which fail to provide adequate defense against bacteria. In contrast, the novel surface engineered by Ren's team moves and responds to the presence of microbes, actively discouraging bacterial adhesion.

Ren's team has also developed a material inspired by the natural cilia found on human cells. These cilia-like structures, covered in micron-sized pillars, can be activated to beat in a rhythmic manner, effectively removing more than 99.9% of surface-attached bacteria and biofilms. In 2025, Ren and his colleagues at Syracuse further enhanced this material by coating it with mucin, a protein that helps human cells repel bacteria.

Moving forward, Ren and his team at the University of Tennessee are focused on integrating active topography into next-generation, microbe-resistant medical devices. Urinary catheters, which are used to drain urine in patients unable to visit the bathroom or control their bladders, are particularly susceptible to biofilm formation.

Replacing these catheters every two to four days can be traumatic and lead to further infections. Ren's team aims to extend the safe usable life of a catheter from days to weeks by creating a prototype catheter lined with the ciliated active topography material. This innovative approach has the potential to significantly improve patient comfort and overall health outcomes.