Liquid-infused surface tuned to resist E. coli adhesion

Liquid-infused surfaces feature an immobilized oil surface layer, giving the material a slipperiness that can prevent bacterial adhesion. This slipperiness can control biological interactions like fouling, or bacterial growth, on medical implants. In their recent article, Sotiri et al. demonstrate the potential applications of liquid-infused surfaces by modifying the material’s hardness and slipperiness to resist E. coli adhesion.

When submerged in an oil, the organic polymer PDMS swells, and a thin layer of immobilized liquid forms on the surface. In their experiment, authors used PDMS samples with different degrees of hardness, manipulating the curing agent and viscosity of the silicone oil to tune the slipperiness. They were surprised to find that changing the hardness of the material made a significant difference in resisting E. coli bacterial adhesion. E. coli’s known stickiness serves as a good model for resistance of other bacteria.

Based on where the material was sticky, versus slippery, the team has been fine-tuning how to pattern wettability on liquid-infused surfaces. Now, they are working to create surfaces that are tuned to stay slippery for a determined amount of time. Controlling how long a material is slippery could stymie bacterial growth while over time allowing cells to grow so medical implants can be incorporated into tissues.

In addition to biomedical applications like reducing infection risks from implant devices or preventing blood clots, liquid-infused surfaces show potential to control industrial biointerfaces. For instance, this method could be used to create new coatings that prevent organisms from colonizing the hulls of boats and make shipping more fuel-efficient. “Being able to define and control a material is the first step in being able to build something that does exactly what you want it to do,” said author Caitlin Howell.

Source: “Tunability of liquid-infused silicone materials for biointerfaces,” by Irini Sotiri, Amanda Tajik, Yang Lai, Cathy T. Zhang, Yevgen Kovalenko, Carine R. Nemr, Haylea Ledoux, Jack Alvarenga, Edythe Johnson, Huseini S. Patanwala, Jaakko V. I. Timonen, Yuhang Hu, Joanna Aizenberg, and Caitlin Howell, Biointerphases (2018). The article can be accessed at https://doi.org/10.1116/1.5039514 .